Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
46C H A P T E R 5 Critical Observations Drawn from Field Survey in EuropePotential Sections for R21 Composite Pavement Database The survey included the examination of several composite pave- ment sections that are candidates for inclusion in the SHRP 2 Renewal Project R21 database (Table 5.1). This database was set up in Phase 1 of the R21 contract to include design, materi- als, climate, traffic, construction, and performance data from selected asphalt concrete (AC)/portland cement concrete (PCC) and PCC/PCC composite pavements. The database includes all inputs from the Mechanistic-Empirical Pavement Design Guide (MEPDG) (1), as well as other available performance data. The surveyed pavements include nine EAC/JPCP sections that exhibited very good performance. Currently, the R21 database includes only one such section (the section in Detroit built in 1993). The exposed aggregate concrete (EAC) surfaces represent the most promising type of thin, high-quality sur- face for composite concrete pavements. The surveyed European pavement sections also include three porous AC surfaces and one stone matrix asphalt (SMA) surface section that exhibited very good performance. Summary of European Field Survey The composite pavement types observed in the Netherlands, Germany, and Austria in the summer of 2008 performed well and were believed by the highway agencies involved to be economical. Composite Concrete Sections The following points were taken from the survey of two-layer PCC in Germany, Austria, and the Netherlands. 1. Two-layer EAC surface over jointed plain concrete pave- ment (JPCP) is being used extensively today in all threecountries visited, as well as in others, such as Belgium. This experience extends for more than 20 years and cov- ers a range of climates, including harsh winter conditions at high elevations and milder sea-level climates. Their per- formance has been exceptional, carrying large volumes of heavily loaded European and international trucks with very little deterioration. 2. The economic advantage of this two-layer pavement lies in the lower-cost, thicker lower concrete layer. All con- tractors and government officials who were asked about this issue believed that the two-layer concrete pavement would be economical wherever high-quality aggregate was expensive and especially where recycled concrete could be used as the lower layer. 3. The exceptional characteristics of the EAC surfacing lies in its noise-abatement abilities (similar to dense AC material), its ability to maintain a long-term friction coefficient and to not polish, and the durability of the surface, enabling it to resist studded tires and other types of wear. 4. The sustainability advantage of this type of pavement is nowhere more evident than on the 300-km A1 motorway across Austria. A1 was gradually reconstructed by recy- cling the existing AC/PCC pavement into the lower layer of a new PCC/PCC pavement. The lower PCC mix was designed to accommodate recycled asphalt pavement (RAP) that had bonded to coarse recycled concrete aggre- gates. The amount of RAP in the lower PCC mix can be as much as 15% of the total coarse aggregate. The remaining RAP is used as base material. The long life achieved with this pavement is also likely to show substantial savings in natural materials, lane closures for maintenance, and acci- dents arising from lane closures. 5. The typical design and materials used in these pavements are as follows: a. Top layer of 5 to 9 cm of exposed aggregate concrete that includes a high-quality, gap-graded, polish-resistant aggregate with a top size of 8 mm. It was recommended
47Pavement Year Layer Country Highway Type Constructed Thicknesses Comments Netherlands Germany Austria A12 A50 A73 N279 N279 A6 A93 A93 A93 A93 A93 A93 A93 A1 A1 A1 A1 AC/CRCP AC/CRCP AC/CRCP EAC/JPCP EAC/JPCP EAC/JPCP EAC/JPCP Long. burlap 2 Long. tining Long. grooved Diamond grind SMA/JPCP EAC/JPCP EAC/JPCP EAC/JPCP EAC/JPCP EAC/JRCP 1998 2002 2007 2000 2000 2008 1995 1995 1995 1995 1999 1995 2004 1993 1999 1994 1963 5 cm porous AC 25 cm CRCP 6 cm AC 7 cm porous AC 25 cm CRCP 6 cm AC 7 cm porous AC 25 cm CRCP 6 cm AC 9 cm EAC 18 cm JPCP 9 cm EAC 18 cm JPCP 5 cm EAC 25 cm JPCP 7 cm EAC 19 cm JPCP 7 cm EAC 19 cm JPCP 7 cm EAC 19 cm JPCP 7 cm EAC 19 cm JPCP 7 cm EAC 19 cm JPCP 3 cm EAC 7+19 cm JPCP 7 cm EAC 19 cm JPCP 4 cm EAC 21 cm JPCP 5 cm EAC 21 cm JPCP 5 cm EAC 20 cm JPCP 6 cm EAC 16 cm JRCP First AC/CRCP project Two-layer porous AC Two-layer porous AC Main construction Section P quartzite Major new construction 13 years of very heavy trucks Sawing and sealing of SMA and joints 19 cm recycled PCC 21 cm recycled PCC 21 cm recycled PCC 20 cm recycled PCC Still in service, badly cracked Table 5.1. European Composite Pavement Sections Included in the R21 Databaseto use 5/8-mm gradation to obtain best surface texture (gap-grading is not a must; gradation overall is situation dependent; 11 cm is too large a maximum size). b. The EAC texture should be measured and specified in two different ways: (1) Texture depth measured by the standard ASTM sand patch procedure. The texture is somewhat varied between countries, but research shows that shallower texture depth reduces noise. The Aus-trian recommendation is to target 0.8 mm. The German contractor also recommended 0.8 mm. (2) The appropriate number of aggregates in a specific 5-cm by 5-cm square area is 55 in Austria. This test provides a check of the spacing of the aggregates. It may be that not achieving this was the main reason for the high noise level on the Detroit EAC. (3) Both of these tests are necessary to control the tex- ture and noise level of the EAC surface.
48c. The cement content of this mix is relatively high. Thick- ness of the top layer should be 5 cm; if it is too thick, seg- regation may occur. d. 19 to 25 cm of lower-cost concrete (often recycled con- crete), placed with dowels and tiebars. Dowel position in the lower lift is helped by adequate thickness of the lower lift, 15 cm minimum for this purpose. The dowel is placed at mid-depth of composite thickness. The upper lift thickness should be at least three times the largest aggregate size. The lower lift has lower cement content. The lower-quality aggregate in the lower lift can be recycled material. Be careful to not sacrifice too much strength. In addition, be careful about using recy- cled materials from nonpavement sources. e. The base layer is composed of unbound aggregate or hot mix asphalt. f. The transverse joints are approximately 5 m, with dowel bars and tiebars across longitudinal joints. g. The construction uses two pavers, one to place the lower layer and the other following immediately behind with the top layer. Mixing can be done with two plants, but it is done in Europe with one plant and specially designed mixers. Before construction, laboratory trials are needed to determine what local materials may be used to achieve appropriate mix. Also required will be the develop- ment of a test strip at MnROAD to give both contrac- tor and researcher an opportunity to develop skills necessary to achieve a successful surface texture. Laboratory tests must be done using project aggre- gates to establish optimum mixture and aggregate gra- dation for construction, ability to texture the surface of slabs, the timing of texturing in slabs, and so forth. The process should begin with laboratory tests to construct test slabs that are sprayed and brushed to ensure that gradation gives the desired texture. Freeze-thaw testing is also recommended. The sand patch test should be used to investigate depth of texturing. Sand in the mix is a concern. In addition, reduce vibrating energy and use T-shaped vibrators. There is also a need to include a superplasticizer in the concrete mixtures. 6. The two layers bond securely; there has been no instance where this wet-on-wet bond has broken. Field observation of cross sections showed a well-bonded upper and lower layer with little to no desegregation between layers. Composite Asphalt Sections The following points were taken from the survey of AC/PCC composite pavements in the Netherlands and a discussion of experience with AC/PCC composite pavements with experts in the Netherlands, Germany, and Austria.1. Two-layer composites featuring asphalt surfaces over JPCP and continuously reinforced concrete pavement (CRCP) are being used in the Netherlands and Germany, as well as in other countries, such as Belgium and the United Kingdom. 2. Porous asphalt surfaces (similar to an open-graded friction course in the United States) are placed over CRCP in the Netherlands, the United Kingdom, Italy, and other coun- tries. Problems mentioned with porous asphalt over CRCP include raveling (which is the major problem requiring future rehabilitation) and filling with fines after a few years, which would negate the low-noise benefit. No reflection cracking has occurred over CRCP for up to 10 years. 3. SMA is used over JPCP and CRCP in Germany and other countries. This experience extends over 10 to 15 years. Reflection cracking is a problem when JPCP is used, and the joints reflect through unless significant efforts are made. Sawing and sealing above transverse and longitudinal joints have been effective in Germany. SMA over CRCP also has been effective in not reflecting through. 4. SMA is used in harsh winter conditions in Germany; porous asphalt is used in milder climates such as the Netherlands, the United Kingdom, and Italy. The recommendation received in these countries (particularly Austria, where serious icing problems occurred) is that porous asphalt not be used in deep-freeze areas, because of the difficulty of controlling icing and the amount of deicing materials needed. Thus, it is not recommended for the MnROAD test site. 5. The performance of both types of surfaces has been excep- tional, carrying large volumes of heavily loaded European and international trucks with very little deterioration over a 10- to 13-year period. 6. The economic advantage of this two-layer pavement lies in the lower cost of the lower concrete layer. All contrac- tors and government officials who were asked about this believed that the two-layer asphalt-surfaced concrete pave- ment would be economical wherever high-quality aggre- gate was expensive and especially where recycled concrete could be used as the lower layer. 7. The exceptional characteristics of the porous asphalt sur- facing include its ability to abate noise (the lowest noise of all known surfaces), to maintain the friction coefficient and to not polish, to prevent splash or spray, and to be renewed quickly whenever needed in the future. Porous asphalt currently is the surfacing used on CRCP in the Netherlands, the main reasons being its low-noise, no- splash-and-spray, and high-friction qualities. Six or more large projects have been built on freeways with this com- posite design, and good performance has been achieved over 10 years. All these projects are in milder climates in the Netherlands.
498. The sustainability advantage of this type of pavement lies in its long-life perpetual-pavement design concept, where the base slab is designed to not fatigue significantly (no punchouts) and the surface can be renewed rapidly. In the Netherlands, only the upper 2.5-cm layer is removed and replaced. The lower 4-cm layer is not removed. 9. The following are the design and materials for the porous AC friction course over CRCP: a. Both a single and a double porous asphalt surface have been constructed. The double-layer porous asphalt, which provides a very low-noise surfacing, is designed as follows: (1) 2.5-cm porous asphalt 4/8 mm (modified with polymer). (2) 4.5-cm porous asphalt 6/11 mm (modified with polymer). b. Timing of placement of the porous AC: The porous asphalt is the last work item on the project. Therefore, after the CRCP is placed there normally is a period of several weeks or months before the AC surfacing is placed. This is done to avoid damaging the final surface by construction traffic. The surface of the CRCP is textured using a longitudinal burlap drag to provide mechanical interlock with the asphalt surfacing. c. A tack coat of 0.2 kg/m2 emulsion is applied twice because of the texturing. d. 19 to 25 cm of lower-cost concrete (often recycled con- crete), placed with sufficient longitudinal reinforcement (e.g., 0.7%) and tiebars. The reinforcement position in the layer is important and should be above mid-depth of the CRCP slab. The lower lift has lower cement content. The lower-quality aggregate in the lower lift can be recycled material, as long as the strength and thickness are sufficient to produce very low fatigue damage. e. A base layer specifically of hot mix asphalt provides sufficient random crack spacing of 1 to 2 m maximum. f. Construction is similar to conventional pavements, where the lower layer is placed, textured, and cured and allowed to gain sufficient strength before the AC layer is placed. This is one of the last items of work to avoid damaging the surface. g. Before construction, laboratory trials are needed to determine what local materials may be used to achieve appropriate mix for the porous asphalt and the lower concrete layer. The asphalt surface typically bonds securely when the lower concrete layer is textured and a tack coat is used. There has been no instance where thiswet-on-wet bond has broken. A double dose of tack coat is used in the Netherlands because of the texturing. Recommendations for Construction of Experimental Composite Pavement Systems Under SHRP 2 Renewal Project R21 Major factors that should be considered in an experiment at MnROAD include the following: 1. Type of AC material used in the surface course. SMA is recommended for the MnROAD site. It has been used suc- cessfully in Germany under a similar climate. Mn/DOT has built several SMAs with success, and these specifica- tions should prove adequate. Sawing and sealing of the transverse and longitudinal joints are recommended. 2. Other asphaltic surfaces, such as Superpave® and rubber- ized surfacing, can be placed. The saw-and-seal technique is recommended for handling reflection cracking for any of these mixtures. 3. The thickness of the lower layer can be varied to provide adequate structure for the I-94 loadings and prevent fatigue damage and cracking. MEPDG provides for a significant thickness reduction with the AC surface, which dampens out temperature and moisture gradients through the slab. It is recommended that the upper layer be held constant at 7 cm. 4. The material used in the lower layer should be recycled concrete (using the large aggregate component only). 5. The material used in the upper layer must be a very high- quality aggregate, such as granite or quartzite, with low potential for polishing. The particles must be reasonably cubical. The maximum texture of 8 mm should not be varied. 6. Wire brushing to achieve the proper texture depth requires care and skill and should be practiced on another section of pavement. Laboratory slabs should be cast to practice the wire brushing to achieve proper texture depth. The 5-cm by 5-cm square test to count the number of aggregate peaks also should be included, with a target value of 55. Reference 1. Mechanistic-Empirical Pavement Design Guide: A Manual of Practice, interim ed. American Association of State Highway and Transporta- tion Officials, Washington, D.C., 2008.
TRANSPORTATION RESEARCH BOARD 2010 EXECUTIVE COMMITTEE* OFFICERS CHAIR: Michael R. Morris, Director of Transportation, North Central Texas Council of Governments, Arlington VICE CHAIR: Neil J. Pedersen, Administrator, Maryland State Highway Administration, Baltimore EXECUTIVE DIRECTOR: Robert E. Skinner, Jr., Transportation Research Board MEMBERS J. Barry Barker, Executive Director, Transit Authority of River City, Louisville, Kentucky Allen D. Biehler, Secretary, Pennsylvania Department of Transportation, Harrisburg Larry L. Brown, Sr., Executive Director, Mississippi Department of Transportation, Jackson Deborah H. Butler, Executive Vice President, Planning, and CIO, Norfolk Southern Corporation, Norfolk, Virginia William A. V. Clark, Professor, Department of Geography, University of California, Los Angeles Eugene A. Conti, Jr., Secretary of Transportation, North Carolina Department of Transportation, Raleigh Nicholas J. Garber, Henry L. Kinnier Professor, Department of Civil Engineering, and Director, Center for Transportation Studies, University of Virginia, Charlottesville Jeffrey W. Hamiel, Executive Director, Metropolitan Airports Commission, Minneapolis, Minnesota Paula J. Hammond, Secretary, Washington State Department of Transportation, Olympia Edward A. (Ned) Helme, President, Center for Clean Air Policy, Washington, D.C. Adib K. Kanafani, Cahill Professor of Civil Engineering, University of California, Berkeley (Past Chair, 2009) Susan Martinovich, Director, Nevada Department of Transportation, Carson City Debra L. Miller, Secretary, Kansas Department of Transportation, Topeka (Past Chair, 2008) Sandra Rosenbloom, Professor of Planning, University of Arizona, Tucson Tracy L. Rosser, Vice President, Corporate Traffic, Wal-Mart Stores, Inc., Mandeville, Louisiana Steven T. Scalzo, Chief Operating Officer, Marine Resources Group, Seattle, Washington Henry G. (Gerry) Schwartz, Jr., Chairman (retired), Jacobs/Sverdrup Civil, Inc., St. Louis, Missouri Beverly A. Scott, General Manager and Chief Executive Officer, Metropolitan Atlanta Rapid Transit Authority, Atlanta, Georgia David Seltzer, Principal, Mercator Advisors LLC, Philadelphia, Pennsylvania Daniel Sperling, Professor of Civil Engineering and Environmental Science and Policy; Director, Institute of Transportation Studies; and Interim Director, Energy Efficiency Center, University of California, Davis Kirk T. Steudle, Director, Michigan Department of Transportation, Lansing Douglas W. Stotlar, President and Chief Executive Officer, Con-Way, Inc., Ann Arbor, Michigan C. Michael Walton, Ernest H. Cockrell Centennial Chair in Engineering, University of Texas, Austin (Past Chair, 1991) EX OFFICIO MEMBERS Peter H. Appel, Administrator, Research and Innovative Technology Administration, U.S. Department of Transportation J. Randolph Babbitt, Administrator, Federal Aviation Administration, U.S. Department of Transportation Rebecca M. Brewster, President and COO, American Transportation Research Institute, Smyrna, Georgia George Bugliarello, President Emeritus and University Professor, Polytechnic Institute of New York University, Brooklyn; Foreign Secretary, National Academy of Engineering, Washington, D.C. Anne S. Ferro, Administrator, Federal Motor Carrier Safety Administration, U.S. Department of Transportation LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior, Washington, D.C. Edward R. Hamberger, President and CEO, Association of American Railroads, Washington, D.C. John C. Horsley, Executive Director, American Association of State Highway and Transportation Officials, Washington, D.C. David T. Matsuda, Deputy Administrator, Maritime Administration, U.S. Department of Transportation Victor M. Mendez, Administrator, Federal Highway Administration, U.S. Department of Transportation William W. Millar, President, American Public Transportation Association, Washington, D.C. (Past Chair, 1992) Robert J. Papp (Adm., U.S. Coast Guard), Commandant, U.S. Coast Guard, U.S. Department of Homeland Security Cynthia L. Quarterman, Administrator, Pipeline and Hazardous Materials Safety Administration, U.S. Department of Transportation Peter M. Rogoff, Administrator, Federal Transit Administration, U.S. Department of Transportation David L. Strickland, Administrator, National Highway Traffic Safety Administration, U.S. Department of Transportation Joseph C. Szabo, Administrator, Federal Railroad Administration, U.S. Department of Transportation Polly Trottenberg, Assistant Secretary for Transportation Policy, U.S. Department of Transportation Robert L. Van Antwerp (Lt. General, U.S. Army), Chief of Engineers and Commanding General, U.S. Army Corps of Engineers, Washington, D.C. *Membership as of June 2010. TRB OVERSIGHT COMMITTEE FOR THE STRATEGIC HIGHWAY RESEARCH PROGRAM 2* CHAIR: Kirk T. Steudle, Director, Michigan Department of Transportation MEMBERS H. Norman Abramson, Executive Vice President (Retired), Southwest Research Institute Anne P. Canby, President, Surface Transportation Policy Partnership Alan C. Clark, MPO Director, Houston-Galveston Area Council Frank L. Danchetz, Vice President, ARCADIS G&M, Inc. Dan Flowers, Director, Arkansas State Highway and Transportation Department Stanley Gee, Acting Commissioner, New York State Department of Transportation Michael P. Lewis, Director, Rhode Island Department of Transportation Susan Martinovich, Director, Nevada Department of Transportation John R. Njord, Executive Director, Utah Department of Transportation Charles F. Potts, Chief Executive Officer, Heritage Construction and Materials Pete K. Rahn, Director, Missouri Department of Transportation Gerald Ross, Chief Engineer, Georgia Department of Transportation George E. Schoener, Executive Director, I-95 Corridor Coalition Kumares C. Sinha, Olson Distinguished Professor of Civil Engineering, Purdue University EX OFFICIO Victor M. Mendez, Administrator, Federal Highway Administration Ron Medford, Acting Administrator, National Highway Transportation Safety Administration John C. Horsley, Executive Director, American Association of State Highway and Transportation Officials LIAISONS Tony Kane, Director, Engineering and Technical Services, American Association of State Highway and Transportation Officials Jeffrey F. Paniati, Executive Director, Federal Highway Administration John Pearson, Program Director, Council of Deputy Ministers Responsible for Transportation and Highway Safety, Canada Margie Sheriff, Director, SHRP 2 Implementation Team, Office of Corporate Research, Technology, and Innovation Management, Federal Highway Administration Michael F. Trentacoste, Associate Administrator, Research, Development, and Technology, Federal Highway Administration RENEWAL TECHNICAL COORDINATING COMMITTEE* CHAIR: Randell H. Iwasaki, Executive Director, Contra Costa Transportation Authority MEMBERS Rachel Arulraj, Director of Virtual Design & Construction, Parsons Brinckerhoff Michael E. Ayers, Director of Pavement Technology Services, American Concrete Pavement Association Thomas E. Baker, State Materials Engineer, Washington State Department of Transportation John E. Breen, Al-Rashid Chair in Civil Engineering, The University of Texas at Austin Daniel DâAngelo, Director and Deputy Chief Engineer, Office of Design, New York State Department of Transportation Rocco A. DePrimo, Manager of Quality Assurance, Utility Manager, Keith and Schnars, P.A. Steven D. DeWitt, Chief Engineer, North Carolina Turnpike Authority Tom Donovan, Senior Right of Way Agent (retired), California Department of Transportation Alan D. Fisher, Manager, Construction Structures Group, Cianbro Corporation Michael Hemmingsen, Davison Transportation Service Center Manager, Michigan Department of Transportation Bruce Johnson, State Bridge Engineer, Oregon Department of Transportation, Bridge Engineering Section Leonnie Kavanagh, PhD Candidate, Seasonal Lecturer, Civil Engineering Department, University of Manitoba Thomas W. Pelnik III, Director, Innovative Project Delivery Division, Virginia Department of Transportation Mary Lou Ralls, Principal, Ralls Newman, LLC John J. Robinson, Jr., Assistant Chief Counsel, Pennsylvania Department of Transportation, Governorâs Office of General Counsel Michael Ryan, Vice President, Michael Baker Jr., Inc. Cliff J. Schexnayder, Eminent Scholar Emeritus, Arizona State University Ted M. Scott, II, Director, Special Projects, American Trucking Associations, Inc. Gary D. Taylor, Professional Engineer Thomas R. Warne, President, Tom Warne and Associates, LLC Gary C. Whited, Program Manager, Construction and Materials Support Center, University of WisconsinâMadison AASHTO LIAISON James T. McDonnell, Associate Program Director for Engineering, American Association of State Highway and Transportation Officials FHWA LIAISONS Cheryl Allen Richter, Infrastructure Research Program Manager, Office of Infrastructure Research and Development, Federal Highway Administration Steve Gaj, Leader, System Management and Monitoring Team, Office of Asset Management, Federal Highway Administration CANADA LIAISON Lance Vigfusson, Assistant Deputy Minister of Engineering & Operations, Manitoba Infrastructure and Transportation *Membership as of May 2010.
Geotechnical Solutions for Soil Improvement, Rapid Embankment Construction, and Stabilization of the Pavement Working Platform (R02) Modular Pavement Technology (R05) Real-Time Smoothness Measurements on Portland Cement Concrete Pavements During Construction (R06E) Composite Pavement Systems (R21) Using Existing Pavement in Place and Achieving Long Life (R23) Preservation Approaches for High Traffic Volume Roadways (R26) ISBN 978-0-309-12887-2 9 780309 128872 9 0 0 0 0
