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Innovative Bridge Designs for Rapid Renewal (2014)

Chapter: Appendix C - UHPC Lab Testing Report

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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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Suggested Citation:"Appendix C - UHPC Lab Testing Report." National Academies of Sciences, Engineering, and Medicine. 2014. Innovative Bridge Designs for Rapid Renewal. Washington, DC: The National Academies Press. doi: 10.17226/22727.
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269 UHPC Lab Testing Report This report was written in conjunction with Hartwell (2011). Introduction Problem Statement Many U.S. highway bridges are currently in need of repair or replacement. Increases in traffic are placing excess stress on highway systems and economic constraints are limiting their renewal. Technologies and solutions must be developed that rapidly and systematically produce long-lasting highway bridges in a way that presents minimal disruption to the public (SHRP 2, 2011). Currently, work is being done to develop accelerated bridge construction (ABC) standards and codes to implement a method of rapid renewal that will address these problems as a part of the Second Strategic Highway Research Program (SHRP 2). One step in the establishment of these new standards and code provisions for ABC’s use across the country, is the design, construction, and testing of a demonstration bridge in Pottawattamie County, Iowa. The demonstration bridge is to be located on U.S. Hwy 6 near Council Bluffs. The design of the three-span precast modular demonstration bridge has been developed by using various details from multiple ABC projects across the country. The goal of this complete ABC design for rapid renewal is to reduce the estimated 6-month road closure for typical construction to a 14-day road closure. The evaluation of promising technologies selected for this demonstration project includes the simultaneous laboratory testing of specific elements or details that are deemed critical to speed of construction and service life. The unique design of the transverse deck joint over the bridge piers is one such instance in this demonstration bridge. Because the trans- verse deck joint uses an emerging innovative material— ultra-high-performance concrete (UHPC)—and the UHPC joint is located in the negative moment region tensile zone, this detail is critical to bridge performance. The UHPC deck joints are the focus of the laboratory testing discussed in the following section. Research Goals and Objectives The main goal of this research is to evaluate the performance of UHPC deck joints in a typical ABC bridge project. Several different testing needs for the UHPC joints have been identi- fied. While a few of these needs are being addressed by research- ers around the country, some aspects were evaluated through lab testing intended to support the design process. The lab tests conducted and their objectives follow: • Test 1: Grinding of the UHPC closure joint material for the longitudinal and transverse joint closures between the pre- cast deck modules 44 Evaluate the grindability of the cast-in-place UHPC in relation to the accelerated construction schedule. • Test 2: Placement, handling, and quality of the UHPC material at the intersecting closure joints 44 Evaluate the constructability of intersecting, cast-in- place UHPC joints with respect to the flow characteris- tics and properties of the material. 44 Qualitatively assess the feasibility of the UHPC joint placement procedure. • Test 3: Serviceability and strength of the transverse bridge deck joint at the pier 44 Evaluate the negative bending performance of the module- to-module transverse connection detail at the piers. 44 Determine the cracking moment at this location. 44 Determine the ultimate moment capacity at this location. Additional investigations for the demonstration bridge were conducted but not included in this report. They are live- load testing of the demonstration bridge and direct tensile bond testing of the UHPC. Arrangement of the Report The following section of this report summarizes the back- ground for this project and presents a review of relevant A p p e n d I x C

270 literature and past work regarding UHPC in bridge design. Subsequent sections discuss the different test methods and materials used in this research, the qualitative and quantita- tive results, and the conclusions and recommendations from the testing program. Background This section presents a summary of the broader SHRP 2 Renewal Project R04 initiative and a review of relevant literature in the area of UHPC. The purpose of this section is to provide an overview that shows how this research fits theory and practice. Project Background Second Strategic Highway Research Program The Second Strategic Highway Research Program, under which this project is funded, focuses on safety, renewal, reli- ability, and capacity. This project, Project R04, focuses on “developing technologies and institutional solutions to sup- port systematic rehabilitation of highway infrastructure in a way that is rapid, presents minimal disruption to users, and results in long-lasting facilities” (SHRP 2, 2011). Further, the objective of SHRP 2 Project R04 is to “develop standardized approaches to designing, constructing, and reusing (including future widening) complete bridge systems that address rapid renewal needs and efficiently integrate modern construction equipment” (SHRP 2, 2011). The project includes four phases which provide for research and development/design of the rapid renewal demonstration bridge up through construction and field demonstration. Typical bridges, characterized as bridges with up to three spans and a maximum span length of 200 ft, are the focus because of the opportunity for widespread application. This research is the result of Project R04 Phase III Task 10C, which calls for laboratory testing of the handling and constructability of the UHPC joint material. While Task 10C was the primary research conducted by the team at Iowa State University, additional investigations for the demonstration bridge were performed, including live-load testing of the dem- onstration bridge and direct tensile-bond testing of the UHPC. Bridge Description The design of the three-span precast modular demonstration bridge—which is the most prominent physical manifestation of the R04 project—was developed by the Iowa Department of Transportation (Iowa DOT) and the design engineer, HNTB Corporation, using various details from several other ABC bridges across the country and around the world. The new bridge will replace a concrete haunched girder bridge built over Keg Creek in 1953 (Figure C.1). The new demonstration bridge, which is to represent a typi- cal, standardized ABC bridge design, is a precast modular bridge system which includes precast approach pavement slabs. The precast column and cap beam construction for the piers will be connected by using grouted couplers, while the precast superstructure deck modules will create a semi-integral abutment allowing rapid construction. On the deck, moment- resisting UHPC joints will connect the deck modules and cre- ate no open deck joints across the span. The SHRP 2 Project R04 demonstration bridge will be the first bridge in the United States with moment resisting UHPC joints at the piers. At 204-ft, 6-in. long and 47-ft, 2-in. wide, the new bridge will con- sist of a pair of 67-ft, 3-in. end spans and a 70-ft, 0-in. center span. Six precast deck modules connected by the longitudi- nal UHPC closure joints make up the bridge cross section (Figure C.2 and Figure C.3). By creating a complete ABC design for rapid renewal, the design engineer has been able to reduce the estimated 6-month road closure required for typical construction to 14 days. Since US-6 in Pottawattamie County is a primary highway route, it provides an excellent platform to showcase the ABC rapid renewal concept for typical bridges. The evaluation of design concepts contained in the dem- onstration project and the R04 standardized details includes the simultaneous laboratory testing of specific elements that are found to be critical to speed of construction and service life. The unique design of the transverse deck joint over the bridge piers is one such example in this demonstration bridge. Because the transverse deck joint employs an emerg- ing innovative material in UHPC, and the UHPC joint is the tension reinforcement through the transverse connection over the piers, it is critical to bridge performance. Figure C.4 shows the precast bridge deck being added to the piers and Figure C.5 illustrates the complete bridge. Figure C.1. Existing U.S. Hwy 6 bridge over Keg Creek.

271 Source: Iowa Department of Transportation, 2011a. Figure C.2. Bridge plan view. Source: Iowa Department of Transportation, 2011a. Figure C.3. Bridge deck cross section. Source: HNTB Corporation. Figure C.4. Precast deck modules. Source: Iowa DOT Office of Bridges and Structures, 2011b. Figure C.5. Completed SHRP 2 Project R04 demonstration bridge.

272 Relevant UHPC Material Background As the United States faces the challenge of renewing its aging highway infrastructure, the longevity and durability of new structures are of particular interest. Research into many differ- ent materials and techniques to achieve durability has taken place. UHPC, a new class of cementitious material, is one tech- nology that is increasingly being considered to provide durabil- ity and longevity in highway infrastructures because of its advanced material behaviors (Graybeal, 2009). While wide- spread use of UHPC has not yet taken place in the United States, multiple state departments of transportation have employed UHPC in recent demonstration projects. Project R04 uses the patented mix, Ductal, developed by Lafarge Canada. Material background, characteristics, and present applications of UHPC relating to the SHRP 2 Project R04 are discussed in the next section. Material Background and Characteristics The development of concrete materials known as UHPC is one of the newest advances in current concrete products. Devel- oped in Europe beginning in the early 1990s, the first commer- cial UHPC product became available in the United States in 2000. In Design and Field Testing of Tapered H-Shaped Ultra High Performance Concrete Piles (Vande Voort, 2008), the author discusses the material characteristics that define the range of cementitious products known as UHPC. Generally, UHPC has a compressive strength that is greater than 22 ksi, contains fiber reinforcement, and uses powder components that help to eliminate some of the typical limitations of normal concrete. Additionally, Graybeal states that “UHPC has a dis- continuous pore structure that reduces liquid ingress, signifi- cantly enhancing durability” when it is compared with normal strength and high-performance concretes (HPC) (2011). The low permeability is attributed to the fine powders and chemical reactivity which create an extremely compact matrix and small, discontinuous pore structure (Perry and Royce, 2010). A typical mix of UHPC contains silica fume, ground quartz, sand, cement, fibers, superplasticizer, and water. Researchers in Europe have been at the forefront of the UHPC material testing and literature. However, increasingly, studies into this emerging material have commenced in the United States. Benjamin Graybeal has completed wide-ranging in-depth testing on the advanced material characteristics of UHPC. Graybeal (2006) reports that when compared with normal strength concrete, UHPC displays significantly enhanced material properties. Notably, compressive strength, tensile strength, rate of strength gain, and several durability properties significantly exceed those of normal concrete. While steam treatment of UHPC initially improves the material’s properties considerably—increasing compressive strength by 53%, modulus of elasticity by 23%, and essentially eliminating long-term shrinkage—UHPC still shows very high compres- sive strengths no matter what type of curing is employed. The time needed to reach initial set for UHPC was between 12 and 24 hr, which is longer than normal concrete. However, once the initial set takes place, UHPC gains compressive strength rap- idly. The speed of the setting time and strength gain can be controlled with different mix additives. The tensile strength was found to be higher than normal concrete (both pre- and posttensile cracking). With and without steam treatment, the tensile strength was found to be 1.3 ksi and 0.9 ksi, respectively. Cyclic testing for durability characteristics showed that the UHPC performs very well across the range of tested condi- tions, and even cracked UHPC cylinders exhibited extremely limited permeability and deterioration. Graybeal’s broad material testing regimen provided a base of information critical to the development of current demonstration details that use UHPC in highway structures. Vande Voort (2008) extensively discusses UHPC material characteristics and explains how the low porosity of the UHPC microstructure is the significant factor behind the material’s superior dura- bility properties. Horszczaruk (2004) and Graybeal and Tanesi (2007) con- ducted abrasion resistance testing on high-strength fiber- reinforced concrete and UHPC by using the ASTM C944 standard procedure (ASTM, 1999). Horszczaruk focused on 12.0 ksi to 14.5 ksi compressive strength concretes that included larger aggregates than are present in any UHPC mix design. Graybeal and Tanesi conducted abrasion resistance testing on UHPC after different curing protocols and differing surface treatments: cast, blasted, and ground. They found that steam-based curing significantly affects the abrasion resistance of the material. Untreated specimens lost nearly 10 times the amount of mass compared with specimens undergoing steam- curing treatment. Additionally, smoother textures tended to be more resistant to abrasion than is the blasted finish. Ductal, the patented UHPC mix from Lafarge Canada that is commercially available in the United States, was developed by three companies—Lafarge, Bouygues, and Rhodia— nearly two decades ago. Ductal is composed of silica fume, ground quartz, sand, cement, high-tensile-strength steel fibers, high-range water reducer, and water. The high-tensile- strength steel fibers included in the mix are 0.008 in. in diam- eter and 0.5 in. long. When Ductal is used, the silica fume, ground quartz, sand, and cement are combined into a premix that arrives in bags along with the steel fibers and high-range water reducer. Ductal JS1000 is the specific mix recom- mended when UHPC is being used as a joint closure material. The product data sheet from Lafarge Canada contains further material information, batching, and placement guidelines for the Ductal JS1000 product (Lafarge Canada).

273 Current Bridge Applications UHPC has been used in many different bridge components. Applications range from UHPC I-girders and complete redeck- ing systems to UHPC joint closures and precast concrete piles. The most-prominent applications of UHPC in bridge super- structure components are discussed in this section. I-GIrder In the United States, two simple-span prestressed concrete girder bridges have been constructed with UHPC I-girder shapes. The Mars Hill Bridge in Wapello County, Iowa, was the first to be constructed in 2005 by Wapello County, the Iowa DOT, and the FHWA (Figure C.6). The bridge is a 111-ft single- span bridge with a three-girder cross section at 9-ft, 7-in. spac- ing and a 4-ft overhang. The UHPC I-girders are modified Iowa 45-in. bulb tee sections. To save material in the section, the web width was reduced by 2 in., the bottom flange by 2 in., and the top flange by 1 in. (Bierwagen and Abu-Hawash, 2005). The Virginia DOT constructed the second bridge using UHPC I-girder shapes. One 81.5-ft-long span of the 10-span Route 624 Bridge over Cat Point Creek was built with five UHPC I-girders. The girders were 45-in.-tall bulb tee beams and contained no conventional steel stirrups for shear re inforcement because the steel fibers present in the UHPC provided adequate shear resistance (Ozyildirim, 2011). BulB douBle Tee GIrder Another deployment of UHPC in bridge construction in the United States involves the design and implementation of a UHPC bulb double tee girder or pi section in Buchanan County, Iowa (Figure C.7). The three-span bridge (112 ft, 4 in. long, 24 ft, 3 in. wide) used three pi sections in the 51-ft, 2-in. center span. The Iowa DOT worked in collaboration with the FHWA’s Turner–Fairbank Laboratory, Iowa State Universi- ty’s Bridge Engineering Center, and Massachusetts Institute of Technology to develop the UHPC pi section (Keierleber et al., 2007). deckInG SySTem A two-way ribbed precast slab system, or waffle slab, was developed to capitalize on the strength and durability charac- teristics of UHPC. The longevity of bridge decks could be increased by UHPC’s low permeability, and the strength of the material helps reduce the mass of material required. This waffle slab system has undergone testing at Iowa State Uni- versity’s Bridge Engineering Center, and construction of the bridge in Wapello County by the Iowa DOT took place in the fall of 2011. FIeld-caST JoInT cloSureS In two instances UHPC has been used as a deck joint closure material in the United States (Figure C.8). Two bridges in New York State used UHPC as a joint closure material between precast deck panels. The New York State DOT used the UHPC joint fill material in the transverse deck joints of the Route 23 Bridge in Oneonta and the longitudinal deck Source: Bierwagen and Abu-Hawash, 2005. Figure C.6. UHPC I-girder bridge, Wapello County, Iowa. Source: Berg, 2010. Figure C.7. Pi-girder bridge, Buchanan County, Iowa. Source: Perry and Royce, 2010. Figure C.8. UHPC deck closure joints.

274 joints of the Route 31 Bridge in Lyons. However, unlike the current demonstration project, the transverse deck joints in the Oneonta bridge were located in the positive bending moment region, placing the UHPC joint in compression. Graybeal (2010) conducted testing on the UHPC bridge deck connections used in the New York State DOT’s bridges under static and cyclic structural loading at the Turner– Fairbank Highway Research Center’s Structural Testing Lab- oratory. Simulated wheel patch loads were applied adjacent to the UHPC joints for four transverse joint specimens. The test specimens were arranged and tested so that flexural stresses, which would be caused by traffic, were oriented parallel to the joint. It is important to note that the test setup focused on local flexural behaviors of the deck only. The test did not account for global flexural behaviors of the deck and girder system. Neglecting overall flexural effects of the deck and girder system, Graybeal found no significant UHPC or inter- face cracks parallel to the transverse joint. Graybeal also tested two specimens representing the longitudinal joint connection. Wheel patch loads were applied adjacent to the joint, and the specimen was oriented so that flexural stresses occurred per- pendicular to the joint. Graybeal suggested that the field-cast UHPC joint wouldn’t necessarily debond at the connection interface under the low loads and small direct flexure in the longitudinal direction. Methods The evaluation of promising technologies for the SHRP 2 accel- erated bridge construction demonstration project includes the simultaneous laboratory testing of specific elements or details that are found to be critical to speed of construction and dura- bility. The unique design of the transverse deck joint over the bridge piers is one such instance in the demonstration bridge. Because the transverse deck joint utilizes an emerging innova- tive material in ultra-high-performance concrete (UHPC) and the UHPC joint experiences high levels of flexural tension, the material is critical to the bridge’s performance and thus the focus of the lab testing. Several areas of testing for the UHPC joints were identi- fied during the design of the demonstration bridge. While a few of these areas have been addressed by researchers around the country, some aspects of the demonstration bridge were examined through further lab testing to support the bridge’s design. The lab tests conducted for this study include abrasion testing of the UHPC closure joint material, constructability testing of the intersecting deck joints, and strength and ser- viceability testing of the transverse deck joint at the pier. The methods used in this testing regimen were selected to address these objectives: to determine the grindability of cast-in- place UHPC, to assess the feasibility of intersecting deck joint placement, and to evaluate the bending performance of the module-to-module transverse connection detail at the piers. UHPC Abrasion Testing Abrasion testing of cast-in-place UHPC was conducted to determine the early age grindability of the material when used in the demonstration bridge. Specifically, a period of time in which the contractor can grind the joint material without causing damage to the joints or equipment had to be identified. The demonstration bridge specifications indicated that the UHPC closure joint attain 10,000 psi of compressive strength before it should be ground. This test helped to deter- mine the relative ease of grinding for the material after the 10,000 psi threshold has been reached. Experimental vari- ables for this test included the maturity of the UHPC and the specimen surface finish. Mixing and Casting UHPC Cylinders To complete the abrasion testing, UHPC cylinders were cast. From one cylinder, four test specimens were produced. The batching and casting was completed in 1 day with three batches of the same UHPC mix design proportions. In total, 24 UHPC cylinders, each 4 in. by 8 in., were cast from three batches of UHPC to create the test specimens. Twelve of the cylinders were cut in half to create four surfaces per cylinder for testing. Each surface was then treated as a separate specimen. The other 12 cylinders were used in compressive strength tests that were used to correlate maturity and compressive strength of the UHPC to abrasion test results. Cylinders were cured at 40°F, 70°F, and 100°F and were tested 2, 4, 7, and 28 days after casting (Table C.1). Ductal JS1000, from Lafarge Canada, was the UHPC pre- mix material used for the abrasion test specimens. The UHPC mix designed by Lafarge Canada included Ductal JS1000 premix, water, Chryso Premia 150 superplasticizer, and steel fiber. UHPC mix design proportions are included in Table C.2 and Table C.3. The batching procedure was adapted from the procedure recommended by Lafarge Canada for the Ductal JS1000 premix Table C.1. Specimen Curing and Testing Matrix Days After Placement 40F Cure 70F Cure 100F Cure 2 4 specimens 4 specimens 4 specimens 4 4 specimens 4 specimens 4 specimens 7 4 specimens 4 specimens 4 specimens 28 4 specimens 4 specimens 4 specimens

275 in an Imer Mortarman 750 mixer to batch the UHPC mix design (Lafarge Batching Procedure). A Lancaster Products 1.5-ft3 mixer was used to mix the two 0.58-ft3 batches and one 0.40-ft3 batch of UHPC for the test specimens (Figure C.9). Abrasion and Compressive Strength Tests Three surface finish types were tested for grindability during the abrasion testing: a rough top surface, a diamond cut sur- face, and a smooth formed surface (Figure C.10). After curing the cylinders at the various temperatures, four specimens were produced by cutting each cylinder in half. For one cylin- der at each cure temperature and time, one rough top surface, one smooth form surface, and two diamond cut surfaces were tested. To evaluate the UHPC material for grindability, testing was completed following ASTM C944, the Standard Test Method for Abrasion Resistance of Concrete or Mortar Surfaces by the Rotating-Cutter Method (ASTM, 1999). For fabricated concrete or mortar-based specimens, this test helps indicate the relative wearing resistance. ASTM C944 uses a drill press with an abrading cutter rotating at 200 rotations per minute. The normal force exerted on each specimen surface in this test is 22 ± 0.2 lbf. The rotating cutter head leaves a 3.25-in.- diameter abraded circular area (Figure C.11 and Figure C.12). Following the ASTM C944 standard, the initial mass of each specimen was determined to the nearest 0.1 g. The Table C.2. Abrasion Test Specimen, UHPC Mix Design 1 (0.58-ft3 batch) Material Weight (lb) Mix Proportion (%) Ductal JS1000 premix 79.9 87.4 Water 4.7 5.2 Chryso Premia 150 1.1 1.2 Steel fiber 5.7 6.2 Total 91.4 100.0 Table C.3. Abrasion Test Specimen, UHPC Mix Design 1 (0.40-ft3 batch) Material Weight (lb) Mix Proportion (%) Ductal JS1000 premix 54.8 87.4 Water 3.2 5.2 Chryso Premia 150 0.7 1.2 Steel fiber 3.9 6.2 Total 62.7 100.0 Figure C.9. Lancaster Products mixer. Figure C.10. Diamond cut and rough top surface finishes. specimen was then clamped into the testing device such that no rotation could take place. To ensure the quality of each test, special care was taken with the shaft of the rotating cut- ter head to ensure that each specimen surface was normal. Once properly secured in the device, the motor was started and the cutter was slowly lowered into contact with the spec- imen. Following continual abrasion of the specimen for 2 min, the specimen was removed from the testing device, cleared of dust and debris, and massed again to the nearest

276 0.1 g. This process was repeated two additional times for each individual specimen. In total, 12 abrasion tests were conducted on each test day. Four tests were completed for each of the three curing temperatures at 2, 4, 7, and 28 days after batching. Compressive strength tests were simultaneously conducted on corresponding cylinders of the same age and curing tem- perature using ASTM’s Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens (ASTM C39). To ensure the ends of the cylinders were smooth and parallel, the ends of each cylinder were cut before testing. Because of the high strength of the UHPC, capping compound was not used during the compressive strength testing. Joint Constructability Testing A full-scale deck joint mock-up was constructed to evaluate the constructability of intersecting cast-in-place UHPC joints, qualitatively assess the feasibility of the UHPC joint placement procedure, and provide an opportunity to demon- strate casting the material for bridge designers and contrac- tors. Effectively casting the UHPC deck joints is essential to the construction schedule and performance of the SHRP 2 ABC demonstration bridge project. This mock-up, which replicated the conditions in the demonstration bridge, pro- vided an opportunity to understand the flow characteristics and properties of the UHPC mix design with respect to the actual conditions. This helped the bridge designer and con- tractor plan material staging and placement. Designing and Constructing Intersecting Joint Formwork Formwork for a representative portion of the intersection region of transverse and longitudinal UHPC deck joint was designed and constructed for the constructability testing (Figure C.13). The finished intersecting joint specimen was 6 ft, 6 in. long by 7 ft, 4 in. long in the transverse and longitu- dinal joint directions, respectively. The transverse joint, which runs perpendicular to the bridge traffic, measured 16 in. wide, while the longitudinal joint—which runs parallel to the direction of traffic—measured 6 in. wide (Figure C.14). Each joint was 8.5 in. thick, matching the precast module concrete deck thickness. The specimen contained all of the steel reinforcement in the joint detail, including those that protruded from the precast deck modules. To replicate the demonstration bridge conditions fully, the specimen was constructed with a 2% cross slope. 3.5” Figure C.11. Rotating cutter head. Rotating Cutter Head Specimen 22lbf Applied Figure C.12. ASTM C944 test setup. Transverse Direction Longitudinal Direction 2% Cross Slope Figure C.13. Intersecting joint specimen formwork.

277 To replicate the proposed demonstration bridge UHPC placement technique, acrylic glass bulkheads, which aimed to prevent the formation of cold joints, were fabricated and installed (Figure C.15). In the test specimen, the bulkheads were located in the longitudinal joint approximately 2 in. from the transverse joint. The placement of the vertical bulk- heads in the longitudinal joints allowed for continuous place- ment of the transverse closure joint. Mixing and Casting Intersecting Joint Specimen The UHPC mix design that was specified by Lafarge Canada for the SHRP 2 ABC demonstration bridge was used during the constructability testing of the intersecting joint detail. The JS1100RS 60/40 mix design included Ductal Light Grey Premix, water, Chryso Premia 150, Chryso Optima 100, and steel fibers. A technical service engineer from Lafarge Canada was present during the batching and casting of this specimen (Table C.4). Under the supervision of the Lafarge Canada representative, batching was completed for the entire intersecting joint speci- men. For each 5.11-ft3 batch, 14 50-lb bags of Ductal Light Grey Premix were emptied into the drum and mixed to gain homogeneity. Once completely mixed, the Premia 150, Optima 100, and water were added. The batch was then mixed until the turning point was reached. At the turning point, the wetted batch changed from its granular mix state to a semiplas- tic state; at that point the steel fibers were incorporated into the batch. After the steel fibers were fully integrated, the batch could then be discharged (Lafarge Batching Procedure). The total volume of the intersecting joint specimen was 9.54 ft3. Because the Imerman 750 mixer used in the lab is limited to a 5.11-ft3 batch of UHPC and because cylinders for compressive strength tests needed to be cast as well, the specimen was cast in three batches. By using the acrylic glass vertical bulkheads, the transverse joint could be par- tially filled with the first batch and then completed with the second (Figure C.16). In an attempt to gain a homogeneous Source: Iowa Department of Transportation, 2011a. Figure C.14. UHPC deck joint details. Figure C.15. Acrylic glass vertical bulkhead. Table C.4. Constructability Test Specimen, UHPC Mix Design 2 (5.11-ft3 batch) JS1100RS 60/40—Light Grey Premix Material Weight (lb) Mix Proportion (%) Ductal JS1100 premix 700.0 86.74 Water 47.8 5.92 Chryso Premia 150 5.7 0.71 Chryso Optima 100 3.8 0.47 Steel fiber 49.7 6.16 Total 807.0 100.00

278 placement and eliminate a horizontal cold joint in the trans- verse joint, the first batch was agitated in the mold to disrupt the drying “skin” that began to form within 5 min of place- ment. The remaining UHPC from the second batch was then used to place one side of the longitudinal joint. Finally, the third batch filled the last portion of the longitudinal joint as well as the 18 cylinders, each 4 in. by 8 in., used for compres- sive strength testing. The UHPC for the entire specimen was placed from the low end of the 2% cross slope to the high end. As recommended for the demonstration bridge, plywood top forms were attached as the formwork filled (Figure C.17). At the high end of the joint, “chimneys” were constructed in the top form to allow overfilling with UHPC, build up hydrostatic head pres- sure, and ensure that the entire joint was filled. While casting the specimen, no vibrating of the UHPC was needed because it is a self-consolidating material. After the mock-up was cured and removed from the forms, it was cut up into several sections to examine consolidation and locations of potential cold joints. Transverse Joint Strength and Serviceability Testing The module-to-module transverse connection used in the SHRP 2 ABC demonstration bridge was a unique and critical detail that had neither been implemented in a bridge nor tested to quantify structural performance (Figure C.18). To evaluate the negative bending performance of this detail, a mock-up of the connection was constructed and subjected to increasing levels of moment. Testing was completed through static and cyclic testing at service-level conditions, as well as static ultimate moment conditions. Designing and Constructing Full-Scale Transverse Connection Specimen A full-scale specimen replicating the module-to-module trans- verse connection at the pier was designed and constructed in the Iowa State University Structural Engineering Laboratory to allow for testing of the connection details. The specimen had a total length of 40 ft, 6 in. and comprised two prefabricated deck modules connected with the transverse UHPC joint under investigation. The specimen length was chosen so that the nega- tive moment inflection points were located inside the speci- men’s ends. Each precast deck module consisted of two W30X99 steel girders cast compositely with a concrete deck that was 7 ft, 4 in. wide and 8.5 in. thick. The W30X99s used in the prefabri- cated deck modules were 20 ft long and were connected by two MC18X42.7 diaphragm members. These members constituted the steel frame of each module. The steel frames for the prefabricated deck modules were fabricated in Muscatine, Iowa, and shipped to the laboratory at Iowa State University. In the laboratory, the modules were constructed in an upside-down orientation so that the con- crete deck could be cast on the ground (Figure C.19). The two steel frames were placed in their respective deck slab forms on arrival. All epoxy-coated reinforcing steel bars present in the deck slab were placed and tied before setting the frames. General requirements for the hardware, structural steel, and reinforcement bars used in the prefabricated deck mod- ules were as follows: • ASTM A709 grade 50W structural steel; • High-strength ASTM A325 type III bolts; • ASTM A563 heavy hex nut grade DH3; • ASTM F436 type III washers; and • Grade 60 epoxy-coated rebar. Figure C.16. Placement of transverse UHPC joint. Figure C.17. Plywood top forms.

279 CV-HPC-D mix, an Iowa DOT high-performance con- crete bridge deck mix specific for the western region of Iowa, was used for the specimen’s deck slab. The mix (Table C.5) contains river rock commonly found in western Iowa. Eight and a half cubic yards of HPC were needed for the two deck modules. In addition, 24 cylinders, each 4 in. by 8 in., and six beams, each 6 in. by 6 in. by 3 ft, were cast for compressive and flexural strength tests (ASTM C39 and ASTM C78). For safety reasons, as noted previously, the specimen was cast in an upside-down orientation. Once cast, each deck module was positioned on supports, one temporary and one Figure C.18. Module-to-module transverse connection detail. Figure C.19. Prefabricated deck module construction.

280 permanent, then the two modules were connected via four steel angle plates (Figure C.20 and Figure C. 21). The steel angles were designed to be the compressive force path through the transverse module-to-module connection detail. Similarly, the transverse UHPC joint would act as the tension force path for the connection detail. The specimen was supported by temporary supports under the transverse joint formwork until the UHPC material was cured. This casting sequence was chosen to replicate the demonstration bridge design’s simply supported condition for dead load and continuously supported condition for live load. Casting the Transverse UHPC Joint Using the UHPC mix design and batching procedure specified by Lafarge Canada, the transverse joint was cast in two 5.11-ft3 batches (Table C.4). In addition, 45 cylinders, each 4 in. by 8 in., were cast for compressive strength testing at 1, 2, 4, 7, and 28 days. The cylinders were cured at 60°F, 70°F, and 90°F to evaluate strength at temperatures that could occur during the SHRP 2 ABC demonstration bridge construction period. Before placing the UHPC joint, the adjoining HPC deck surfaces were prepared as recommended by Lafarge Canada. The HPC surfaces were removed from the forms, brushed with a steel-brush grinding head, and pressure washed with water. On the morning of the UHPC placement, the HPC surfaces were wetted to attain saturated surface dry condi- tions during UHPC placement. Figure C.22 shows joint and form preparation and UHPC placement. According to the project specifications, once the UHPC material reaches 14,000-psi compressive strength, traffic may be allowed on the demonstration bridge. This meant that specimen testing needed to commence immediately when the 14,000-psi compressive strength threshold was reached. On the basis of results from the UHPC in the constructability test- ing, the investigators expected the threshold would be reached 4 days after placement. The entire load testing frame for the specimen was constructed and load actuators positioned before placement of the transverse UHPC joint so that testing could commence as soon as the UHPC reached 14,000-psi compres- sive strength. Instrumentation for the Transverse Module-to-Module Connection Specimen To monitor the behavior of the deck and deck joint, strain lev- els were monitored throughout the thickness of the deck at locations on, in, or near the joint. A combination of embedded bonded strain gauges, surface-mounted strain gauges, and string potentiometers for deflection were installed on the specimen to analyze the performance of the entire transverse module-to-module connection (Figure C.23 and Figure C.24). Bonded strain gauges were affixed to reinforcing bars in both precast HPC deck slabs and in the transverse UHPC joint. The specimen was instrumented at likely locations for cracks to occur. Those locations were as follows: • To monitor strains in the prefabricated deck panels, embed- ded bonded gauges were placed on the steel hairpins where the longitudinal deck reinforcement terminates. Twelve Table C.5. HPC Mix Proportions Material Relative Proportion (by volume) Cement 0.126 Fly ash 20% max replacement by weight (mass) Water 0.148 Coarse aggregate 0.300 Class V aggregate 0.366 Air 0.060 Figure C.20. Completed deck module. Figure C.21. Transverse UHPC deck joint detail.

281 embedded bonded strain gauges were used on the upper and lower legs of the hairpins at locations directly over the steel beams and at midspan of the deck between the beams on both superstructure modules. In addition, eight surface- mounted strain gauges (three on the top surface of the deck and one on the bottom for each module) were used as well. An additional six embedded bonded strain gauges (three in each deck module on the top mat of reinforcement) were placed on longitudinal reinforcing bars at the termination of the hairpin lap splice. • To identify strain levels at the interface of precast HPC deck panel and the UHPC joint, 12 surface-mounted gauges (three on the top surface, three on bottom surface for each interface) were used. • To quantify strain at the centerline of the UHPC joints, 12 embedded bonded strain gauges were used on the upper and lower legs of the hairpins at the transverse centerline of the joint corresponding to the locations of each steel beam and at the longitudinal centerline of the deck between the beams. In addition, six surface mounted strain gauges were mounted on the top and bottom surfaces of the UHPC joint at corresponding locations to the embedded strain gauges. 44 Eight embedded bonded strain gauges were placed on the straight transverse lacer bars within the UHPC joint. 44 Four embedded bonded strain gauges were mounted to the surfaces of the steel angle connectors between oppos- ing steel beams across the joint. • Specimen displacements were measured with seven string potentiometers mounted to the laboratory floor (three directly under the centerline of the transverse joint, one at each bearing location, and one at the transverse centerline of each module). (See Figures C.25 and C.26.) Calculating Testing Load Levels Design moment values were obtained from the demonstration bridge design engineer, HNTB. Using the AASHTO HS-20 vehicle and a conservative lateral live-load distribution factor of 1.0, Service Level I design live-load moment was calcu- lated at -394 kip-ft. The design moment for Service Level II was -512.2 kip-ft. Ultimate design moment capacity for the Figure C.22. UHPC joint preparation and placement.

282 Figure C.23. Connection instrumentation locations, plan view.

283 module-to-module transverse connection was -2,016 kip-ft. Because of the possibility of an HS-20 load on the other spans of the continuous bridge deck, a +74-kip-ft live-load moment was also possible. Conducting Service-Level Static Testing Testing of the module-to-module transverse connection spec- imen was performed up to Service Level II moment. Loads were applied with two hydraulic actuators each fitted with load cells and connected to spreader beams (Figure C.27 and Figure C.29). The spreader beams allowed for load application, replicating the demonstration bridge’s bearing support condi- tions at the pier. Lubricated steel plates acted as the bearing points for load application (Figure C.28). The lubricated plates allowed the specimen and spreader beam to act independently. Four days after the placement of the transverse UHPC joint, when the cast-in-place UHPC reached the specified 14,000-psi Figure C.24. Connection instrumentation locations, section view. Figure C.25. Embedded bonded strain gauges in HPC deck. Figure C.26. Surface-mounted strain gauges on top of deck. compressive strength threshold, the actuators were placed in deflection control and the joint formwork removed. Three incremental load tests were performed through Ser- vice Level I and up to Service Level II moment conditions. The incremental load test was completed with the actuators in load control. Using load control and lubricated steel bear- ing plates for the tests allowed for replication of the bearing conditions in the demonstration bridge. During the incre- mental tests, the specimen underwent visual inspection on the top and bottom deck surfaces. On completion of the incremental load testing, the cyclic load testing through the full range of service-level condi- tions commenced. One million load cycles were completed over a period of 10 days. Visual inspection and marking of cracking took place every 250,000 cycles. This allowed for the detection of cracks and further monitoring for crack propagation in the HPC deck panels and in the transverse UHPC joint.

284 Conducting Service-Level Testing with Connection Retrofit After analyzing results from the initial service-level load testing and observing the formation of undesirable cracks, HNTB, the design engineer, designed a retrofit for the transverse module- to-module connection (Figure C.30 and Figure C.31). The ret- rofit employed high-strength steel rods mounted just under the deck surface to posttension the entire connection and lower total tensile strain levels present in the HPC deck and UHPC joint to below the expected cracking threshold. Four 1-in.-diameter high-strength threaded rods were installed following the attachment of the ASTM A709 grade 50W steel brackets to the W30X99 beams. The high-strength rods were initially posttensioned to achieve an effective force of 60 kips per rod at each location. Once the retrofit detail was successfully installed, the incremental static service-level load testing through Service Level II moment was conducted in the same manner as previously described. When service-level testing of the 60-kip-per-rod posttensioned retrofit was com- pleted, the high-strength rods were posttensioned to 70 kips per rod. The service-level testing was repeated at the 70-kip posttensioning force level as previously described. Conducting Ultimate Moment Capacity Testing Once the static testing of the modified detail was completed, the posttensioning rods were removed. The final test was conducted to determine the ultimate moment capacity of the original transverse module-to-module connection at the pier. To complete the ultimate load testing, larger capacity actuators replaced those used for the service-level static and cyclic testing (Figure C.32). By incrementally loading the specimen in load control through its expected capacity (2,016 kip-ft) to failure, the performance of the connection could be studied, and the ultimate moment capacity of the connection was determined. Results and discussion Quantitative and qualitative results of the primary laboratory testing regimen carried out for abrasion testing, joint construc- tability testing, and transverse joint strength and serviceability testing are presented in this section along with the results of various material tests (e.g., compressive strength of concrete, flexural strength of concrete, etc.) that accompanied the pri- mary testing regimen. Figure C.27. Load frame for service- level testing. Figure C.28. Lubricated steel bearing plates. Figure C.29. Load test setup.

285 Material Property Tests UHPC Quality Control Tests Quality control testing during the UHPC batching process in the laboratory at Iowa State University included temperature readings as well as static and dynamic flow testing. The test- ing was done according to Lafarge’s flow testing procedure based on ASTM C230. Results of the quality control testing are presented in Table C.6 and Table C.7. UHPC Strength Tests AbrAsion TesTing bATch Twelve 4-in.-diameter cylinders were tested for compressive strength in accordance with ASTM C39 to establish the matu- rity of UHPC Mix Design 1 (Table C.2) used in the abrasion testing. Compressive strength results from the 4-in. UHPC cylinders are presented in Figure C.33. Source: Iowa Department of Transportation, 2011a. Figure C.30. Connection retrofit detail. Figure C.31. Connection retrofit installed. Figure C.32. Actuators for ultimate moment capacity testing.

286 Table C.6. Joint Constructability: UHPC Quality Control Test Results Batch Time Mix Temp Finish (F) Ambient Temp (F) Flow Start Finish Static (in.) Dynamic (in.) 1 9:55 a.m. 10:10 a.m. 85.0 64.0 8.50 9.25 2 10:27 a.m. 10:38 a.m. 84.0 64.0 9.13 10.00 3 11:07 a.m. 11:22 a.m. 82.0 66.0 9.13 10.00 Table C.7. Joint Strength and Serviceability: UHPC Quality Control Test Results Batch Time Mix Temp Finish (F) Ambient Temp (F) Flow Start Finish Static (in.) Dynamic (in.) 1* 10:00 a.m. 10:23 a.m. 100.0 75.5 6.00 N/A 2 11:16 a.m. 11:36 a.m. 60.0 75.5 9.75 10.00 3 11:48 a.m. 12:08 p.m. 60.1 75.6 9.75 10.00 4 12:40 p.m. 1:02 p.m. 60.0 75.6 N/A N/A *Batch not used. Figure C.33. Compressive strength of UHPC Mix Design 1 (abrasion testing).

287 The compressive strengths varied for the curing tempera- tures of 40°F, 70°F, and 100°F. The 28-day compressive strengths ( f ′c) for 40°F, 70°F, and 100°F were 11,100 psi, 16,300 psi, and 21,600 psi, respectively. Joint ConstruCtability testing batCh Eighteen 4-in.-diameter cylinders were tested for compressive strength in accordance with ASTM C39 to establish the maturity of the UHPC Mix Design 2 (Table C.4) used in the joint con- structability testing. Compressive strength results from the 4-in. UHPC cylinders cured at 70°F are presented in Figure C.34. transverse Joint strength and serviCeability testing Forty-five 4-in.-diameter cylinders were tested for compres- sive strength in accordance with ASTM C39 to establish the maturity of the UHPC Mix Design 2 used in the transverse joint strength and serviceability testing. Fifteen cylinders each were cured at 60°F, 70°F, and 90°F to replicate potential field curing temperatures and determine strength variations of the mix design. Compressive strength results from the 4-in. UHPC cylinders are presented in Figure C.35. UHPC Mix Design 2, designed specifically for the SHRP 2 Project R04 demonstration bridge and used in the joint con- structability and transverse joint strength and serviceability testing, reached 10,000-psi compressive strength in approxi- mately 2 days and 14,000-psi compressive strength in 4 days. The 28-day strength ( f ′c) of the UHPC used in the final two testing procedures was approximately 17,000 psi. HPC Strength Test transverse Joint strength and serviCeability testing batCh Twenty-four 4-in.-diameter cylinders were tested for com- pressive strength in accordance with ASTM C39 to establish the maturity of the Iowa DOT CV-HPC-D mix design used in the prefabricated deck modules for the transverse joint strength and serviceability testing. Compressive strength results from the 4-in. HPC cylinders are presented in Fig- ure C.36. The 28-day compressive strength ( f ′c) of the deck HPC for the prefabricated modules was approximately 5,800 psi. Figure C.34. Compressive strength of UHPC Mix Design 2 (joint constructability).

288 Figure C.35. Compressive strength of UHPC Mix Design 2 (strength and serviceability). 2,250 psi 3,951 psi 5,094 psi 6,278 psi 2,470 psi 4,000 psi 5,204 psi 5,789 psi 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 0 5 10 15 20 25 30 Co m pr es si ve St re ng th (p si ) Time (Days) Batch 1 Batch 2 Figure C.36. Compressive strength of HPC (joint strength and serviceability).

289 Flexural Strength Test TranSverSe JoInT STrenGTh and ServIceaBIlITy TeSTInG BaTch Three beams were tested to determine the modulus of rup- ture of the HPC used in the prefabricated deck modules. The beams tested had nominal cross-sectional dimensions of 6 in. by 6 in. and a length of 18 in. and were tested in accordance with ASTM C78 to obtain the modulus of rupture. Flexural strength results for the 6-in. by 6-in. by 18-in. beams are pre- sented in Table C.8. The modulus of rupture (fr) for the HPC used in the deck modules was 439 psi. Taking the modulus of elasticity (Ec) as 57,000 √ f ′c for the HPC, Ec was calculated to be 4,030 ksi (American Con- crete Institute, 2005). Thus, with the modulus of rupture of 439 psi, the expected cracking strain for the precast HPC deck was 110µe. Because no flexural strength testing was completed on the UHPC material, the modulus of elasticity was calculated as 46,200 √ f ′c (Graybeal, 2007). That fell within Berg’s Ec range of 5,800 ksi to 7,800 ksi, allowing the modulus of rupture to be approximated as 1,855 psi (Berg, 2010). The expected crack- ing strain of the UHPC was then calculated to be approxi- mately 250µe. UHPC Abrasion Testing Abrasion testing was completed on the UHPC material to determine the early age grindability of the joints in the dem- onstration bridge. Testing of the UHPC material for abrasion resistance was completed at Iowa State University in February and March 2011. Abrasion Test Results Twelve cylinders were cut into 36 specimens, resulting in three different surface finishes, and subjected to abrasion resistance testing in accordance with ASTM C944. The speci- men identification matrix and identification terminology are presented in Table C.9. Results of the abrasion resistance test- ing at 2, 4, 7, and 28 days are presented in Table C.10 through Table C.13. Taking the maturity of the UHPC into consideration, a plot of the percentage mass loss versus compressive strength for the three different surface finish conditions is presented in Figure C.37. According to the compressive strength test results for the SHRP 2 Project R04 UHPC mix design used in the construc- tability and strength and serviceability testing (Mix Design 2), the UHPC will reach the 10,000-psi compressive strength required for grinding in the project specifications for the demonstration bridge at approximately 2 days if cured at 70°F. The 14,000-psi compressive strength threshold, required in the demonstration bridge project specifications for opening Table C.8. Joint Strength and Serviceability—HPC Flexural Strength Specimen Max. Applied Load P (lb) Span Length L (in.) Width at Fracture b (in.) Depth at Fracture d (in.) Modulus of Rupture R (psi) B1-28 5301 18 6 6 441.75 B2-28 5433 18 6 6 452.75 B3-28 5081 18 6 6 423.42 Modulus of rupture = 439.31 Table C.9. Abrasion Specimen Identification Matrix 2 Days 4 Days 7 Days 28 Days A  40F A2-1 A4-1 A7-1 A28-1 A2-2 A4-2 A7-2 A28-2 A2-3 A4-3 A7-3 A28-3 A2-4 A4-4 A7-4 A28-4 A2-5 A4-5 A7-5 A28-5 B  70F B2-1 B4-1 B7-1 B28-1 B2-2 B4-2 B7-2 B28-2 B2-3 B4-3 B7-3 B28-3 B2-4 B4-4 B7-4 B28-4 B2-5 B4-5 B7-5 B28-5 C  100F C2-1 C4-1 C7-1 C28-1 C2-2 C4-2 C7-2 C28-2 C2-3 C4-3 C7-3 C28-3 C2-4 C4-4 C7-4 C28-4 C2-5 C4-5 C7-5 C28-5 Example: In A2-1, A = curing temperature, 2 = number of days after pour in which test occurs, and 1 = specimen test number. Note: Specimen Tests 1 through 4 are the rough, cut, or formed surface abrasion resistance tests. Specimen Test 5 is the com- pressive strength test.

290 Table C.10. 28-Day Abrasion Test Results: Day 2 Specimen Age: 2 Days ASTM C 944: Abrasion Resistance of Concrete Surfaces by Rotating Cutter Method Test Date: 2/24/2011 Specimen ID Surface Initial Mass Mass 1 Mass 2 Final Mass Wear Depth Loss of Mass Additional Notesg g g g mm g % A2-1 NA 0.00 0.00% *too soft to test A2-2 NA 0.00 0.00% *too soft to test A2-3 NA 0.00 0.00% *too soft to test A2-4 NA 0.00 0.00% *too soft to test B2-1 rough 1993.10 1991.08 1989.31 1987.85 0.41 5.25 0.26% B2-2 cut 1987.85 1986.63 1985.05 1983.48 0.76 4.37 0.22% B2-3 cut 2020.20 2017.20 2015.90 2014.10 0.59 6.10 0.30% B2-4 form 2016.88 2014.01 2008.08 2002.86 1.25 14.02 0.70% C2-1 rough 1951.30 1950.57 1949.88 1949.40 0.48 1.90 0.10% C2-2 cut 1949.37 1948.48 1948.22 1947.95 0.26 1.42 0.07% C2-3 cut 2016.96 2016.73 2016.52 2016.23 0.23 0.73 0.04% C2-4 cut 1771.24 1770.67 1770.26 1769.93 0.26 1.31 0.07% SHRP 2 Project No R04 - Phase III - Task 10C: Test 2 Table C.11. 28-Day Abrasion Test Results: Day 4 Specimen Age: 4 Days ASTM C 944: Abrasion Resistance of Concrete Surfaces by Rotating Cutter Method Test Date: 2/26/2011 Specimen ID Surface Initial Mass Mass 1 Mass 2 Final Mass Wear Depth Loss of Mass Additional Notesg g g g mm g % A4-1 rough 1454.66 1336.17 1336.17 7.29 118.49 8.15% *Maxed out at 55 sec A4-2 0.00 0.00% *too soft to cut cylinder A4-3 0.00 0.00% *too soft to cut cylinder A4-4 form 2242.74 2121.95 2121.95 6.96 120.79 5.39% *Maxed out at 68 sec B4-1 rough 1841.91 1841.25 1840.79 1840.36 1.55 0.08% B4-2 cut 1840.36 1840.14 1839.96 1839.78 0.58 0.03% B4-3 cut 2004.69 2004.54 2004.39 2004.24 0.45 0.02% B4-4 form 2004.24 2002.23 1999.73 1997.95 6.29 0.31% C4-1 cut 1779.75 1779.6 1779.51 1779.38 0.37 0.02% C4-2 cut 1779.38 1779.25 1779.17 1779.12 0.26 0.01% C4-3 cut 2094.86 2094.77 2094.61 2094.5 0.36 0.02% C4-4 form 2094.5 2094.3 2093.89 2093.39 1.11 0.05% SHRP 2 Project No R04 - Phase III - Task 10C: Test 2

291 Table C.13. 28-Day Abrasion Test Results: Day 28 Specimen Age: 28 Days ASTM C 944: Abrasion Resistance of Concrete Surfaces by Rotating Cutter Method Test Date: 3/22/2011 Specimen ID Surface Initial Mass Mass 1 Mass 2 Final Mass Wear Depth Loss of Mass Additional Notesg g g g mm g % A28-1 rough 1700.7 1699.1 1698.8 1698.5 2.20 0.13% A28-2 cut 1698.5 1698.4 1698.2 1698.1 0.40 0.02% A28-3 cut 1855.3 1855.2 1855.1 1854.9 0.40 0.02% A28-4 form 1854.9 1854.5 1853.9 1853.4 1.50 0.08% B28-1 rough 1959.8 1959 1958.6 1958.3 1.50 0.08% B28-2 cut 1958.3 1958.1 1958 1957.9 0.40 0.02% B28-3 cut 2020.6 2020.4 2020.3 2020.2 0.40 0.02% B28-4 form 2020.2 2019.1 2017.8 2016.4 3.80 0.19% C28-1 rough 1985.4 1984.7 1984.4 1983.7 1.70 0.09% C28-2 cut 1803.7 1803.3 1803.2 1803.1 0.60 0.03% C28-3 cut 2054.1 2053.7 2053.3 2053.1 1.00 0.05% C28-4 form 2053.1 2053 2052.9 2052.6 0.50 0.02% SHRP 2 Project No R04 - Phase III - Task 10C: Test 2 Table C.12. 28-Day Abrasion Test Results: Day 7 Specimen Age: 7 Days ASTM C 944: Abrasion Resistance of Concrete Surfaces by Rotating Cutter Method Test Date: 3/1/2011 Specimen ID Surface Initial Mass Mass 1 Mass 2 Final Mass Wear Depth Loss of Mass Additional Notesg g g g mm g % A7-1 rough 2128.75 2120.59 2116.72 2113.48 7.11 0.34% A7-2 cut 2113.48 2112.62 2111.56 2110.63 1.99 0.09% A7-3 cut 1955.9 1955.23 1954.52 1953.82 1.41 0.07% A7-4 form 1953.82 1951.01 1946.51 1943.64 7.37 0.38% B7-1 rough 1841.96 1839.46 1838.7 1838.17 1.29 0.07% B7-2 cut 1838.17 1837.96 1837.84 1837.75 0.21 0.01% B7-3 cut 2162.22 2162.15 2162.09 2162.02 0.13 0.01% B7-4 form 2162.02 2161.65 2161.09 2160.53 1.12 0.05% C7-1 rough 1983.47 1981.9 1981.03 1980.4 1.50 0.08% C7-2 cut 1980.4 1980.33 1980.22 1980.15 0.18 0.01% C7-4 cut 2103.96 2103.88 2103.84 2103.77 0.11 0.01% C7-3 form 2103.77 2103.63 2103.38 2103.12 0.51 0.02% SHRP 2 Project No R04 - Phase III - Task 10C: Test 2

292 the bridge to traffic, will likely be reached 4 days after place- ment. Thus, the contractor will have roughly 2 days to per- form grinding of the joints from the time the 10,000-psi threshold is reached until opening of the bridge to traffic at 14,000-psi compressive strength. The percentage mass loss for both formed and top finishes at the 10,000-psi compres- sive strength threshold is approximately 0.12%. At 14,000-psi compressive strength of the UHPC mix, the percentage mass loss is approximately 0.07%. Over that 2-day duration, the UHPC’s resistance to abrasion increases by approximately 40%. That would be a significant factor for the contractor in terms of grinding time and accelerated scheduling. Figure C.37 shows that the formed surface and rough sur- face finishes displayed the lowest abrasion resistance. Speci- mens with formed surface finishes exhibited lower abrasion resistance than cut surfaces because of the steel fibers present in the UHPC. At the formed surface, the steel fibers were aligned preferentially, parallel with the surface. Thus, the fibers tended to pull off easily. The fibers lay parallel with the form surface because, as the UHPC flowed along the bottom of the form, the fibers tended to align and lie flat. The rough surface finish generally also included small, entrapped air bubbles, which allowed for easier removal of the UHPC material. As was expected, the cut surface finish had the high- est abrasion resistance. Because the cast-in-place UHPC joints in the Project R04 demonstration bridge are a plywood- top formed surface, the abrasion resistance in the field is expected to most nearly resemble that of the formed surface finish seen in the abrasion tests. Joint Constructability Testing Joint constructability testing was done to qualitatively evalu- ate the intersecting, cast-in-place UHPC deck joints to be used in the demonstration bridge. Specifically, a full-scale mock-up of the intersection between one longitudinal and Figure C.37. Abrasion testing: Percentage mass loss versus strength.

293 one transverse UHPC deck joint was constructed to investi- gate issues relating to casting sequence, material mixing and placement rates, effects of ambient temperature on construc- tion, flow characteristics of the UHPC, and consolidation of material at congested locations. Testing of the UHPC joints for constructability was completed at Iowa State University in April 2011. Constructability Test Results caSTInG Sequence The original proposal for the construction sequence of the demonstration bridge outlined continuous placement of the entire grid of UHPC deck joints (longitudinal and trans- verse). During discussions with the engineer, contractor, and material supplier, several logistical issues arose which chal- lenged the feasibility of full-deck continuous placement. Typical mixers used by Lafarge Canada for UHPC placement mix 5.11 ft3 per batch. On the job site, the mixers are used in pairs to provide a continuous supply of UHPC. Each batch is then discharged into buggies and transported onto the bridge to the placement location. Given the large volume of UHPC needed for the bridge deck joints, continuous placement could be achieved only by using a large number of mixers and laborers. Otherwise, cold joints could potentially form in the UHPC deck joints. As an alternative, Lafarge proposed using stay-in-place acrylic vertical bulkheads to control the location of poten- tial cold joints. As a result of these discussions, a new construction sequence—limiting continuous placement to the transverse joints and allowing vertical cold joints in the longitudinal joints—was suggested for the joint constructability testing and demonstration bridge. A prototype of the stay-in-place acrylic vertical bulkheads (see Figure C.15) was fabricated and used during the joint constructability testing so its per- formance could be evaluated. The acrylic vertical bulkheads were used successfully. amBIenT-TemperaTure eFFecTS on uhpc The extent of the susceptibility to variations in temperature for the workability and flow characteristics of the UHPC mix design was observed during batching of the joint constructa- bility test specimen and the transverse joint strength and service ability test specimen to follow. Ambient air tempera- tures, seen previously in Table C.6, were steady at around 65°F at the time of batching for the intersecting joint speci- men. However, during the batching for the transverse joint strength and serviceability specimen, ambient temperatures were 75.5°F (see Table C.7). Without compensating for the change in ambient air temperature, the workability and flow characteristics of the mixes were much different. When ambient temperatures were 65°F, the temperature of the UHPC on discharge from the mixer ranged from 82°F to 85°F for the intersecting joint specimen’s three batches. Within this range, the UHPC had acceptable flow characteristics for placement. When ambient temperatures were around 75.5°F, the temperature of the UHPC on discharge from the mixer was over 100°F. At this ambient temperature, the UHPC never reached its anticipated flow characteristics in the mixer, thus the batch was rejected. To correct the problem, water in the mix design was replaced by mass with ice and the UHPC material temperature was reduced. When ice was used, the batches could be successfully discharged and placed. The tem- perature upon discharge from the mixer for batches using ice was 60°F. This modification—the replacement of water by mass with ice—enabled extended working time and improved the flow relative to the previous batch. Flow characTerISTIcS and conSolIdaTIon oF uhpc Evaluating the flow of the UHPC around the corners at the intersection of the longitudinal and transverse deck joints was a critical aspect of this test. Adequate consolidation of the UHPC in the joint cross section around steel reinforcement is important to the deck joint performance. During UHPC placement, when the final-mix temperature was limited to a maximum of 85°F, the UHPC material appeared to have ade- quate flow characteristics to achieve good consolidation and flow around corners at the intersections of longitudinal and transverse joints (Figure C.38). After the specimen was cured and removed from the forms, it was cut into several sections to examine consolida- tion and potential cold joints. No significant voids around the steel reinforcing bars were observed (Figure C.39 and Figure C.40). Figure C.38. Joint intersection specimen.

294 The test also validated the use of top forms and chimneys at the high end of the 2% cross slope of the bridge deck at transverse joints. The top forms were applied sequentially as the joint was filled from the lowest elevation to the highest. The chimneys (see Figure C.17) provide additional hydro- static head in the freshly placed UHPC to aid in consolida- tion within the joint. Top forms and chimneys were suggested for use in the demonstration bridge. Instead, three-quarter- inch-high spacer boards were placed below the top forms to build up small hydrostatic head and produce similar results. JoInT InTerSecTIon deTaIl recommendaTIonS Final inspection of the specimen upon removal from the forms allowed for additional observations and recommendations. The proposed stay-in-place acrylic bulkhead successfully allowed for sequential placement of the UHPC, but it also created a possible infiltration plane where water and chemi- cals could access the embedded steel joint reinforcement (Figure C.41). To maintain sequential placement of UHPC in the deck joint grid and avoid possible infiltration planes, a detail for a partial-height, removable acrylic bulkhead was developed and suggested for use in the demonstration bridge (Fig- ure C.42). The removable acrylic bulkheads should be used in the longitudinal joint, and in compression zones where pos- sible (Figure C.43). Placing the bulkheads at those locations will provide better continuity at the interface between the hardened and freshly placed UHPC, which will help prevent the ingress of water and other chemicals. In addition, the Figure C.39. Section of transverse joint, Example 1. Figure C.40. Section of transverse joint, Example 2. Figure C.41. Stay-in-place acrylic bulkhead. Figure C.42. Removable acrylic bulkhead.

295 placement sequence of the UHPC (Figure C.43) will be con- trolled, starting at the lowest elevations through the trans- verse joints over the piers up to the bulkheads. The center-span UHPC joints will be placed last. Transverse Joint Strength and Serviceability Testing Strength and serviceability testing of the module-to-module transverse connection for the SHRP 2 Project R04 dem- onstration bridge was performed to evaluate the negative bending performance of this detail over the piers, deter- mine its cracking moment, and verify the ultimate moment capacity. Testing of the module-to-module transverse con- nection was completed at Iowa State University from July to October 2011. Results Terminology Because of the orientation of the testing specimen in the labo- ratory, the driving surface (or top-of-deck surface) was located on the bottom of the specimen and the bottom-of-deck sur- face was located on the top of the specimen (Figure C.44 and Figure C.45). Refer to Figure C.23 and Figure C.24, which display the locations of all instrumentation for the test specimen pre- sented in the following sections. Service-Level Static Test Results Load testing through live-load Service Levels I and II moment was completed on the specimen (Figure C.46). The range of expected service-level moments for the module connection varied from +74 kip-ft to -538 kip-ft. Loading was completed at 5,000 lbf increments to complete visual inspection of the specimen and check for the appearance of cracks and accrual of damage. Strain levels were monitored with the embedded and surface- mounted strain gauges located throughout the specimen (Fig- ure C.23 and Figure C.24). Strain levels for surface-mounted strain gauges at locations that spanned the HPC-UHPC inter- face exceeded 110µe, the HPC cracking strain, at approximately halfway to Service Level I moment (Figure C.47). By selecting only one longitudinal line of surface mounted strain gauges, it can be seen that, immediately adjacent to the gauges spanning the interface, surface strain levels were well below the HPC cracking strain (Figure C.48). Surface- mounted strain gauges at these locations registered negligible strains throughout. The disparity between immediately adja- cent gauges and the strains registering in excess of the HPC cracking strain across the interface suggested debonding and an opening at the interface between the precast HPC deck and the UHPC joint. Note that the intent of the design for the demonstration bridge was to avoid all cracking in the deck at the transverse joint over the pier, as that would be detrimental to the durability of the deck. Visual inspection of the joint interface at Service Level II confirmed the debonding and substantial opening of the interface suggested in the strain gauge data (Figure C.49). Figure C.43. Proposed placement plan. Figure C.44. Deck surface terminology photograph. Bottom of Deck Top of Deck Figure C.45. Deck surface terminology diagram. Bottom of Deck Top of Deck

296 Figure C.46. Applied moment versus actuator displacement.

297 Figure C.47. Top-of-deck surface mounted strain gauges over the joint interface.

298 Later, inspection during fatigue testing further confirmed the interfacial debonding and opening occurring below service- level conditions. In addition to joint interface debonding and substantial opening, strain levels in the embedded strain gauges regis- tered above the expected HPC cracking strain as well. Fig- ure C.51 through Figure C.53 show the embedded strain gauge data for top-of-deck gauges along longitudinal reinforcement under the two girder lines in the specimen. Figure C.54 through Figure C.56 display strain data for bottom-of-deck gauges along the same longitudinal reinforcement lines. Embedded strain gauge locations and identifications along with row groupings are shown in Figure C.50. At the top of the deck, the groupings of embedded strain gauges show the varying strain seen within the UHPC joint, near the joint interface, and at the hairpin bar termination Figure C.48. Selected surface-mounted strain gauges adjacent to the joint interface. Figure C.49. Joint interface opening. Top of Deck HPC UHPC Interface Opening Crack Developing

299 Figure C.50. Embedded strain gauge location and identification. Figure C.51. Row 1, top-of-deck embedded strain gauges (static).

300 Figure C.52. Row 2, top-of-deck embedded strain gauges (static).

301 Figure C.53. Row 3, top-of-deck embedded strain gauges (static).

302 Figure C.54. Row 1, bottom-of-deck embedded strain gauges (static).

303 Figure C.55. Row 2, bottom-of-deck embedded strain gauges (static).

304 The groupings of embedded strain gauges on the bottom- of-deck reinforcement were located within the UHPC joint and near the joint interface only (Figure C.54 through Fig- ure C.56). Results similar to those in the top of the deck were observed. Maximum strains of 460µe, 520µe, and 420µe were registered near the joint interface reinforcement in the bottom of the deck at S1-3-1B, S1-2-1B, and S1-1-1B, respec- tively. Localized prying effects of the girders could potentially be responsible for the higher strain levels in the bottom-of- deck reinforcement for the UHPC joint in Rows 1 and 3. Strains at two of those locations were observed to exceed the UHPC cracking strain at or before reaching the Service Level II condition. In general, internal strains in the UHPC were lower than in the HPC precast deck at each instrumentation location. As previously discussed, the gauges within 2 in. of the interface in the HPC deck registered the highest strains for all rows in both the bottom and the top of deck. In addition, the prevalence of Figure C.56. Row 3, bottom-of-deck embedded strain gauges (static). location that is 3 ft from the interface (Figure C.51 through Figure C.53). As observed with the surface-mounted strain gauges, the embedded gauges near the interface all exceed the HPC cracking strain before reaching Service Level I condi- tions. In the top-of-deck reinforcement, maximum strains of 540µe, 550µe, and 475µe were recorded in S1-1-1T, S2-2-2T, and S2-3-2T, respectively. Strain in the UHPC joint (J1 and J2 gauges) were relatively lower in the top of the deck, not exceeding 160µe, which is below the expected UHPC crack- ing strain level of 250µe. Nearly all gauges located at the termination of the joint hairpin bar registered strain levels exceeding 110µe before the Service Level II conditions. Those data suggested cracking in the prefabricated HPC deck mod- ules under service-level loading. Cracking was not visually confirmed near the joint in the HPC deck during the incre- mental static loading, but opening and closing of the cracks during cyclic loading made cracking in the HPC clearly visible.

305 the high strains at the termination of the hairpin reinforce- ment in the top of deck means cracking of the HPC is expected. These data suggest that the transverse connection detail was not satisfying the original project aim to avoid cracking in the deck over the pier. Service-Level Fatigue Test Results After the static tests were completed, fatigue testing com- menced. Fatigue tests consisted of loading the specimen through the full service-level moment range for 1,000,000 cycles. The loading rate was one cycle per second, requiring approxi- mately 2 weeks to complete. Strain data for embedded gauges on the top-of-deck reinforcement after the completion of 1,000,000 cycles are presented for gauges in Rows 1, 2, and 3 (Figure C.57 through Figure C.59). The embedded strain results for the fatigue testing gener- ally resembled those from the static testing. Similarly, the gauges near the interface consistently exhibited the highest strains, while the gauges within the UHPC registered the low- est in each of the instrumentation rows. When compared with the static testing results, some higher strain levels at 1,000,000 cycles suggested propagation of cracking and dam- age accrual within the specimen. Visual inspection at the onset of cyclic loading revealed cracking in the precast HPC deck around the joint at roughly half of Service Level I conditions (Figure C.60). Inspection at 250,000 cycles identified cracks in the precast deck up to 10 ft away from the joint. Damage accrual to the specimen during the fatigue test- ing was analyzed by comparing strain values at various cycle counts. Strain accrual data is presented for gauge groupings in Rows 1, 2, and 3 (Figure C.61 through Fig- ure C.66 and Table C.14 through Table C.19). Increases in strains at embedded gauge locations throughout the speci- men suggested the initial cracks were propagated from the incremental static service-level load tests during the fatigue testing. In the bottom-of-deck data for Rows 1 and 3 (Fig- ure C.62 and Figure C.66), the high strain levels within the UHPC joint likely stem from the localized prying effects of the girders protruding into the joint on the bottom of the deck. Figure C.57. Row 1, top-of-deck embedded strain gauges (1,000,000 cycles).

306 Figure C.58. Row 2, top-of-deck embedded strain gauges (1,000,000 cycles).

307 Table C.14. Row 1, Top-of-Deck Strain Accrual Gauge S2-1-2T µe S2-1-1T µe J2-1-T µe J1-1-T µe S1-1-1T µe S1-1-2T µe 3,000 cycles 210 440 146 58 474 172 1,000,000 cycles 250 506 163 73 505 236 Strain increase 19.3% 15.0% 12.1% 27.4% 6.6% 37.6% Table C.15. Row 1, Bottom-of-Deck Strain Accrual Gauge S2-1-1B µe J2-1-B µe J1-1-B µe S1-1-1B µe 3,000 cycles 208 278 155 336 1,000,000 cycles 259 329 200 336 Strain increase 24.4% 18.4% 28.6% 0.0% Table C.17. Row 2, Bottom-of-Deck Strain Accrual Gauge S2-2-1B µe J2-2-B µe J1-2-B µe S1-2-1B µe 3,000 cycles 366 47 78 500 1,000,000 cycles 411 52 88 492 Strain increase 12.3% 10.8% 12.1% -1.7% Table C.16. Row 2, Top-of-Deck Strain Accrual Gauge S2-2-2T µe S2-2-1T µe J2-2-T µe J1-2-T µe S1-2-1T µe S1-2-2T µe 3,000 cycles 288 472 38 42 512 159 1,000,000 cycles 330 542 39 44 518 255 Strain increase 14.5% 14.7% 1.5% 3.6% 1.2% 60.2% Table C.19. Row 3, Bottom-of-Deck Strain Accrual Gauge S2-3-1B µe J2-3-B µe J1-3-B µe S1-3-1B µe 3,000 cycles 241 326 254 365 1,000,000 cycles 288 377 297 349 Strain increase 19.5% 15.9% 16.9% -4.2% Table C.18. Row 3, Top-of-Deck Strain Accrual Gauge S2-3-2T µe S2-3-1T µe J2-3-T µe J1-3-T µe S1-3-1T µe S1-3-2T µe 3,000 cycles 317 414 113 81 458 203 1,000,000 cycles 331 460 127 95 488 314 Strain increase 4.5% 11.1% 12.6% 16.4% 6.5% 54.2%

308 Figure C.59. Row 3, top-of-deck embedded strain gauges (1,000,000 cycles). Figure C.60. Full-depth cracking in precast deck. UHPC Joint HPC Deck Crack 8.5” At 500,000, 750,000, and 1,000,000 cycles, further visual inspection confirmed propagation of the existing cracks and formation of new full-depth cracks in the precast deck panels within 10 ft of the joint. The strain accrual throughout the fatigue testing varied at each location. Generally, the strain levels increased to 28%. At one location, the strain level increased 60%, while at others only a small decrease was observed. These outliers most likely result from the highly sensitive nature of embed- ded strain gauges to localized cracking. In addition, because of the cyclic nature of loading and the frequency of data recordings, the peak strain readings for some gauges could have been missed, causing an apparent decrease in strain at certain locations. As suggested by static testing results, visual inspection dur- ing fatigue testing confirmed early debonding and significant opening at the interface between the precast HPC deck panels and UHPC joint. In addition to debonding at the deck joint interface, cracking in the precast deck panels near the trans- verse joints was observed below Service Level I conditions. To mitigate these serious durability concerns, a modified detail was devised to posttension the deck in this region and mini- mize tensile stresses in the concrete throughout Service Level II without compromising the accelerated construction aspect of the SHRP 2 R04 project. Connection Retrofit Test Results Following fatigue testing, the specimen was modified to include high-strength steel rods mounted just under the deck surface to

309 Figure C.61. Row 1, top-of-deck strain accrual.

310 Figure C.62. Row 1, bottom-of-deck strain accrual.

311 Figure C.63. Row 2, top-of-deck strain accrual.

312 Figure C.64. Row 2, bottom-of-deck strain accrual.

313 Figure C.65. Row 3, top-of-deck strain accrual.

314 Figure C.66. Row 3, bottom-of-deck strain accrual.

315 By contrast, applying 70 kips posttensioning force in each of the rods minimized or negated the tensile strain across the inter- face entirely when loaded to Service Level I. All surface-mounted strain gauges spanning the interface registered below the HPC cracking strain until after the Service Level I conditions were applied (Figure C.74). Tensile strain data across the interface revealed a maximum 29µe at Service Level I moment. None of the embedded strain gauges, top- and bottom-of-deck, exceeded 110µe until Service Level II conditions were applied (Figure C.75 through Figure C.78). The 70-kip-per-rod post- tensioning force was recommended for application in the SHRP 2 Project R04 demonstration bridge. Once again, embedded strain gauges within the UHPC joint consistently registered strains below those in the HPC deck for each of the instrumentation rows in both the top- and bottom-of-deck reinforcement. The 60 kips of post- tensioning force per rod reduced strain levels from the previous incremental static testing but not completely below the HPC posttension the entire joint region and prevent any possible cracking of the deck or joint in this region (Figure C.30). The retrofit detail was tested through the full range of service-level moments with a 60-kip posttensioning force per rod and again with a 70-kip posttensioning force per rod. The static test results for surface-mounted strain gauges across the joint interface (Figure C.67 and Figure C.74) and embedded strain gauges in Rows 1, 2, and 3 (Figure C.68 through Figure C.71 and Fig- ure C.75 through Figure C.80) are presented in this section. The 60-kip posttensioning force in each of the rods reduced tensile strain across the joint interface such that the HPC cracking strain was not reached until Service Level I condi- tions (Figure C.67). A maximum tensile strain of 200µe was recorded across the joint interface at Service Level I moment. Embedded strain gauges never exceeded 110µe before Service Level I conditions. However, strains did exceed the HPC cracking strain in the top-of-deck embedded gauges before reaching Service Level II (Figure C.68 through Figure C.71). Figure C.67. Top-of-deck surface-mounted strain gauges over interface (60-k retrofit).

316 Figure C.68. Row 1, top-of-deck embedded strain gauges (60-k retrofit).

317 Figure C.69. Row 2, top-of-deck embedded strain gauges (60-k retrofit).

318 Figure C.70. Row 3, top-of-deck embedded strain gauges (60-k retrofit).

319 Figure C.71. Row 1, bottom-of-deck embedded strain gauges (60-k retrofit).

320 Figure C.72. Row 2, bottom-of-deck embedded strain gauges (60-k retrofit).

321 Figure C.73. Row 3, bottom-of-deck embedded strain gauges (60-k retrofit).

322 Figure C.74. Top-of-deck surface-mounted strain gauges over interface (70-k retrofit).

323 Figure C.75. Row 1, top-of-deck embedded strain gauges (70-k retrofit).

324 Figure C.76. Row 2, top-of-deck embedded strain gauges (70-k retrofit).

325 Figure C.77. Row 3, top-of-deck embedded strain gauges (70-k retrofit).

326 Figure C.78. Row 1, bottom-of-deck embedded strain gauges (70-k retrofit).

327 Figure C.79. Row 2, bottom-of-deck embedded strain gauges (70-k retrofit).

328 Figure C.80. Row 3, bottom-of-deck embedded strain gauges (70-k retrofit).

329 Figure C.81. Ultimate capacity moment versus deflection. cracking strain before Service Level I moment. The 70 kips of posttensioning force per rod, however, did lower strains below the HPC cracking strain until Service Level II at each instrumentation row. Ultimate Capacity Test Results On completion of static testing for the modified detail, the posttensioning rods were removed and the transverse module- to-module connection detail was tested to ultimate moment capacity. Figure C.81 shows the moment-displacement curve for the specimen during testing. Strain data for the embedded gauges along reinforcement Rows 1, 2, and 3 (Figure C.82 through Figure C.87) were analyzed in combination with qual- itative observations to determine the failure mechanism for the transverse module-to-module connection detail. Embedded strain gauge data immediately adjacent to the joint interface in the top-of-deck reinforcement entered the inelastic range, suggesting yielding (2,000µe) at approxi- mately 1,500 kip-ft to 1,600 kip-ft of applied moment (see Figure C.82 through Figure C.84). All gauges embedded on the top-of-deck reinforcement at those locations behaved in

330 Figure C.82. Row 1, top-of-deck embedded strain gauges (ultimate).

331 Figure C.83. Row 2, top-of-deck embedded strain gauges (ultimate).

332 Figure C.84. Row 3, top-of-deck embedded strain gauges (ultimate).

333 Figure C.85. Row 1, bottom-of-deck embedded strain gauges (ultimate).

334 Figure C.86. Row 2, bottom-of-deck embedded strain gauges (ultimate).

335 Figure C.87. Row 3, bottom-of-deck embedded strain gauges (ultimate).

336 this manner. This result corresponded to the specimen enter- ing into inelastic deformation around the same applied moment in Figure C.81. Similarly, bottom-of-deck embed- ded strain gauge data immediately adjacent to the joint interface indicated yielding at approximately 1,600 kip-ft to 1,800 kip-ft of applied moment (see Figure C.85 through Figure C.87). With increased loading, the opening at the interface between the HPC deck and the UHPC joint widened. Cracks from service-level testing propagated and widened through- out the precast deck (Figure C.88). At 1,660 kip-ft, two large cracks (one in each deck module) spanning the entire width of the specimen became apparent approximately 1.5 in. from the joint interface on the bottom-of-deck surface. As the specimen was pushed well beyond service-level moments, reinforcement in the HPC deck near the UHPC interface Figure C.88. Interface opening and crack propagation. UHPC Joint HPC Deck Figure C.89. Girder–deck interface. Girder Pulling Away began to yield. Eventually, the moment-displacement curve entered into the nonlinear region, and correspondingly, strains in reinforcement near the joint began to deform plas- tically (see Figure C.82 through Figure C.87). Throughout ultimate moment capacity testing, the W30X99 girders appeared to be slowly pulling away from the joint. All of the cracking in the UHPC joint and HPC deck could be seen accumulated locally where the girder appeared to pull away (Figure C.89). The two large cracks parallel to the joint interface contin- ued to widen, and eventually the UHPC suffered tensile rup- ture near the shear studs located in the joint (Figure C.90). See Figure C.91 for even more fractures. Cracking in the precast deck exposed the outermost reinforcement hairpins that entered into the joint allowing for pullout (Figure C.92). Load application continued, and the specimen reached a peak moment of 2,239 kip-ft before successive fractures of multiple Figure C.90. UHPC rupture (top- and bottom-of-deck).

337 hairpin reinforcement bars acted as the ultimate mode of fail- ure for the transverse connection. Deformation in the bottom flange of the W30X99 girders was identified as the test progressed and the specimen underwent large deflections (Figure C.93). In addition, during the ultimate moment capacity testing, the slip critical bolted connections went into bearing and caused local deformation in the flange holes. Upon failure, the total deformation of the specimen at the centerline of the UHPC joint was 9.3 in. (Figure C.94). Conclusions This section presents conclusions for the abrasion, construc- tability, and strength and serviceability tests. The different test conclusions summarize the important issues and recommen- dations from the qualitative and quantitative testing data. UHPC Abrasion The objectives for the abrasion testing were to determine the early age grindability of the UHPC material to help the con- tractor with accelerated scheduling on the demonstration project. Several conclusions and recommendations for the joint material were made. • Assuming a 70°F curing temperature, the UHPC will reach the 10,000-psi compressive strength required for grinding at approximately 2 days. • Assuming a 70°F curing temperature, the material will reach the 14,000-psi compressive strength threshold required to open the bridge to traffic after 4 days. Thus, the contractor will have roughly 2 days to grind the UHPC joints for the bridge deck surface before the bridge reopens. Figure C.91. Bottom-of-deck at failure. Figure C.92. Exterior hairpin reinforcement (opposite sides). HPC Spalling Figure C.93. Bottom flange deformation. Flange Deformation

338 • Specimens with a formed surface finish exhibited less abra- sion resistance than specimens with cut surfaces because the steel fibers in the UHPC lay parallel with the surface and tended to pull off easily. Fiber alignment was attrib- uted to material flow on the bottom surface of the mold. • Specimens with a rough surface finish generally included small entrapped air bubbles, which allowed for easy removal of the UHPC material. • If the demonstration bridge’s field cast joints have a formed surface finish because of a plywood top form, the abrasion resistance in the field is expected to most nearly resemble that of the abrasion resistance results of formed surface specimens. • If the field-cast joints have an unfinished top surface, the abrasion resistance in the field is expected to most nearly resemble that of the abrasion resistance results of rough surface specimens. • For the formed surface finish, abrasion resistance of the UHPC at 10,000-psi compressive strength will likely be about 40% lower than the abrasion resistance roughly 2 days later when the UHPC reaches 14,000-psi compressive strength. • For the rougher, unfinished surface, abrasion resistance of the UHPC at 10,000-psi compressive strength will likely be about 27% lower than the abrasion resistance when the UHPC reaches 14,000-psi compressive strength roughly 2 days later. Joint Constructability The completed construction and casting of the intersecting deck joint mock-up specimen helped formulate a proposed UHPC placement plan. • Ambient temperatures at the time of batching are very important to the flow characteristics of the UHPC. • At an ambient temperature of 65°F, the temperature of the UHPC on discharge from the mixer ranged from 82°F to 85°F. Within that range, adequate flow characteristics to achieve good consolidation and flow around corners were observed. • At an ambient temperature of 75.5°F, the temperature of freshly mixed UHPC reached 100°F and the flow character- istics were inadequate for placement and consolidation. • Consequent replacement of water with ice by mass in the batch reduced the temperature of freshly mixed UHPC to 60°F and once again allowed for acceptable flow character- istics of the UHPC. • At satisfactory discharge temperatures, the acceptable flow characteristics created no significant voids around steel reinforcing bars at the intersection of longitudinal and transverse deck joints. • The UHPC should be placed from areas of lowest to high- est elevation while applying top forms as the deck joints are filled. A small chimney should be constructed at the high- est elevation to provide hydrostatic head in the UHPC and aid material consolidation. • Full-depth stay-in-place acrylic bulkheads create a possible infiltration plane for water and chemical access to the embedded steel joint reinforcement and should be avoided if possible. • To maintain controlled sequential placement of the UHPC and avoid infiltration planes, a partial-height removable acrylic bulkhead should be used in the longitudinal joint at locations where the UHPC material will likely be in compression. Transverse Joint Strength and Serviceability Testing of the transverse module-to-module connection over the pier identified the likely cracking moment and deter- mined the ultimate capacity of the section. Many results and recommendations were made from the testing regimen regard- ing serviceability of the deck over the connection. Service-Level Static Testing • During both static and fatigue testing, surface-mounted strain gauges spanning the interface between the prefab- ricated deck modules and the UHPC joint indicated early debonding and significant opening at the interface. • Visual observation of the interface at and below service- level load conditions confirmed the early debonding and opening of the HPC-UHPC interface. • In addition to debonding at the joint interface, embedded strain gauges near the interface registered strains above the HPC cracking strain level (110µe) at approximately half of Service Level I moment conditions, suggesting cracking is likely to occur in the prefabricated deck modules. Figure C.94. Overall specimen deflection.

339 Service-Level Fatigue Testing • Visual inspection at the onset of the 1,000,000-cycle service- level fatigue testing confirmed cracking in the precast HPC deck near the joint interface. • Strain accrual during fatigue testing suggested propagation of existing cracks in the specimen. Visual inspection through- out the fatigue testing confirmed propagation of existing cracks and formation of new full-depth cracks in the pre- fabricated deck modules within 10 ft of the joint. Connection Retrofit Testing • To mitigate the serious durability concerns at the trans- verse module-to-module connection over the pier, a modi- fied detail—which would not compromise the accelerated construction aspect of the project—was devised and imple- mented. The modified detail posttensioned the deck in this region to minimize tensile stresses in the concrete through service-level conditions. • Static service level testing when 60 kips of posttensioning force was applied in each of the four rods for the modified module connection detail reduced the tensile strain across the interface, but not sufficiently to reduce strains below HPC cracking levels before Service Level I conditions. • Static service-level testing indicated that the application of 70 kips of posttensioning force negated the tensile strain across the interface entirely until after Service Level I con- ditions were reached. • Strains measured with surface-mounted strain gauges did not exceed the HPC cracking strain until after Service Level I conditions were reached. Strains measured with embedded strain gauges throughout the specimen did not exceed the HPC cracking strain until after Service Level II conditions were reached with 70 kips per rod of post- tensioning force. • The 70-kip posttensioning force per rod was recommended for application in the demonstration bridge to reduce the likelihood of deck cracking over the piers and increase deck durability at the transverse joint interface. Ultimate Capacity Testing • The overall specimen moment versus deflection plot indi- cated inelastic deformation of the specimen around 1,500 kip-ft to 1,600 kip-ft of applied moment. • Top-of-deck reinforcement began yielding at approxi- mately 1,500 kip-ft to 1,600 kip-ft of applied moment, corresponding to the inelastic deformation of the entire specimen. • Bottom-of-deck reinforcement suggested yielding between approximately 1,600 kip-ft and 1,800 kip-ft of applied moment. • The W30X99 girders slowly pulled away from the joint. UHPC tensile rupture occurred near the shear studs located in the joint and connected with two large cracks in the HPC deck parallel to the joint interface that had formed and widened as load increased. • Spalling at the edges in the precast deck exposed the exte- rior module hairpins and allowed for rebar pullout. Suc- cessive fracture of multiple hairpin reinforcement bars entering the transverse joint was the ultimate mode of fail- ure for the connection. • The actual ultimate moment capacity of the transverse module-to-module connection (2,239 kip-ft) was deter- mined to be approximately 10% greater than the expected ultimate moment capacity (2,016 kip-ft). Through the project’s full-testing regimen, the UHPC deck joints were evaluated for their use in the ABC demonstration bridge. Provided that the UHPC mix design’s sensitivity to ambient temperature effects were accounted for, the UHPC provided excellent flow characteristics, workability, and con- solidation during placement of the intersecting deck joints. In addition, the accelerated rate of compressive strength gain and higher cracking strain level of the UHPC made it well suited for its application in this ABC project. While the UHPC displayed several superior material charac- teristics with respect to the durability and strength of the deck joints themselves, the direct tensile bond strength between the UHPC and the HPC deck on display during the strength and serviceability testing was a concern. Testing revealed that the interface between the transverse UHPC joint and HPC deck underwent early debonding and significant opening well below service-level moment conditions. This raised concerns as to the durability of the module-to-module transverse joint connec- tion for the demonstration bridge. Consequently, a post- tensioning retrofit detail was developed and tested to eliminate opening at the interface and cracking in the HPC deck around the transverse joint over the pier. With an adequate post- tensioning force per rod, the retrofit successfully limited strains levels to below the HPC cracking strain. Because of the interfacial bond issues observed over the course of this testing, further investigation into the direct tensile bond strength between the UHPC and HPC is recommended. This testing would better evaluate the durability of the longitu- dinal and transverse UHPC deck joints present in the ABC demonstration bridge and help determine the long-term viabil- ity of this UHPC deck joint detail as a solution in future ABC projects.

Next: Appendix D - Field Demonstration Project Construction »
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TRB’s second Strategic Highway Research Program (SHRP 2) Report S2-R04-RR-1: Innovative Bridge Designs for Rapid Renewal documents the development of standardized approaches to designing and constructing complete bridge systems for rapid renewal.

The report also describes a demonstration project on US-6 over Keg Creek near Council Bluffs, Iowa, that was completed in 2011 using the accelerated bridge construction standards developed as part of Renewal Project R04.

The following three videos were also produced related to the Keg Creek project:

ABC for Everyday Bridges (18:39) highlights the specific techniques used to deliver a new bridge with only a 10-day closure.

One Design—10,000 Bridges (9:46) describes a tool kit for designing and constructing bridges that brings home the benefits of accelerated bridge construction techniques so local contractors can use typical equipment to build bridges quickly and efficiently.

Time-Lapse Video (1:30) shows accelerated bridge construction techniques being used by a local contractor with standard equipment to replace the Keg Creek three-span bridge.

SHRP 2 Renewal Project R04 also developed an Innovative Designs for Rapid Renewal: ABC Toolkit that describes standardized approaches to designing and constructing complete bridge systems for rapid renewals, as well as a case study on the accelerated bridge construction techniques used in the I-84 bridge project in New York. In addition, the project developed a half- and full-day presentations to help facilitate training on the accelerated bridge process to interested parties.

In June 2013, SHRP 2 released a Project Brief on Renewal Project R04.

​Software Disclaimer: This software is offered as is, without warranty or promise of support of any kind either expressed or implied. Under no circumstance will the National Academy of Sciences or the Transportation Research Board (collectively "TRB") be liable for any loss or damage caused by the installation or operation of this product. TRB makes no representation or warranty of any kind, expressed or implied, in fact or in law, including without limitation, the warranty of merchantability or the warranty of fitness for a particular purpose, and shall not in any case be liable for any consequential or special damages.

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