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E-1 A P P E N D I X E Delaware Construction Report Delaware Department of Transportation (DelDOT) executed the Port Penn/Pole Bridge Road overlay project in late fall of 2016. The approximately 2.2-mile overlay project was paved on December 02, 2016 and located near Middletown in north-central part of Delaware. The project started on Port Penn Road at the intersection with Route 9 (east end) and extended to partially on Pole Bridge Road (west end). The project included one-inch milling of existing surface layer and placement of two-inches overlay. Typical paving width was 11 feet. The project had three test sections to evaluate the effects of recycling agents (rejuvenators) on the performance of asphalt mixtures with high RAP and RAS content. Diamond Materials was the general contractor for this project. Figure E.1 shows the general project location and a typical section where left side was already paved with surface course and right side shows the milled surface before overlay placement. Three test sections were placed along the entire length of the project limits (Figure E.2). Both Port Penn/Pole Bridge Roads are two-way undivided rural road located in the north central side New Castle County in Delaware. Typical roadbed width was 26 feet including two 11-feet travel lanes (paved) and 2-feet unpaved grassy shoulder on each side. This section of roadway relatively horizontal with numerous intersections and driveways. The traffic on this road is moderate to light and consists of occasional truck traffic to/from the port. Figure E.1: Project Site showing Surface Course and Milled Surface.
E-2 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios with unknown thickness. Under this study, three test sections were placed as surface course. Each of the three test sections had different surface mix design using 9.5 mm Superpave mixture as shown in Table E.1. Figure E.2: Project Location. Figure E.3: Typical Full Depth Field Core. Before milling, the existing surface had some longitudinal cracks. When the researcher was present during the construction, the existing surface was already been milled. But the milled surface did not show any cracking which indicates that the longitudinal cracking on the existing surface was top down superficial cracking. Figure E.3 shows a typical full depth core extracted after the paving. The existing structure was found to be about six inches asphalt layer constructed at different times. The subbase below the HMA appeared as mix of crushed concrete and millings
Delaware Construction Report E-3 E.1 MATERIALS AND MIXTURES All three test sections used DelDOTâs standard Type C (12.5 mm) Superpave mixture designed with 160 gyrations. A PG 64-28 neat binder was used in all mixtures. The source of RAP was unknown; it came from several different highway sections. RAS was produced by shredding and grinding post consumers' waste shingles from multiple sources. Shingles were shredded on-site at the plant. The shingles were 100% passing the #3/8 inch sieve. The Control Mix (Test Section 1) had virgin aggregate from three different stockpiles along with 20% RAP and 4% RAS. The virgin aggregate came from several sources. The control mix had 0.4% warm mix additive by weight of total asphalt content. During design it was considered that the combined contribution of RAP and RAS was 2.2 percent recycled binder in the control mixture resulting in 5.8 percent total asphalt content. The T2 Mix (Test Section 2) had a PG 64-28 virgin binder, and virgin aggregate from three different stockpiles along with 29% RAP and 4% RAS. As previously mentioned, the virgin aggregate came from several sources. The T2 mix had 0.8% recycling agent by the weight of total asphalt content. The T2 plus warm mix additive mix (Test Section 3) had similar components as the T2 Mix (Test Section 2), except that it had additional 0.25% warm mix additive by weight of total mixture. Figure E.4 through Figure E.6 present the quality control data for the mixtures. Job mix formulas are also included in the quality control report. Table E.1: Test Sections Mixture Description. Section No. Section Name Description Additive/Rejuvenator Dosage 1 Control Mix 20% RAP + 4% RAS with 3.6% PG 64-28 virgin binder 0.4 % warm mix additive by weight of total asphalt content 2 T2 29% RAP + 4% RAS with 3.2% PG 64-28 virgin binder 0.8 % T2 by weight of total asphalt content 3 T2 plus warm mix additive 29% RAP + 4% RAS with 3.2% PG 64-28 virgin binder 0.25 % warm mix additive + 0.8 % T2 by weight of total asphalt content
E-4 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Figure E.4: Mixture Design for Test Section 1.
Delaware Construction Report E-5 Figure E.5: Mixture Design for Test Section 2.
E-6 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Figure E.6: Mixture Design for Test Section 3.
Delaware Construction Report E-7 E.2 DESCRIPTION OF ASPHALT PLANT All three mixtures were produced at an asphalt mix plant located on the Southeast side of Wilmington, Delaware. Figure E.7 shows an overview of the hot mix plant. The average distance between the plant and the test sections was about 25 miles or approximately 35 minutes away by vehicle. The counter flow drum plant had a capacity of 400 tons per hour. In addition, a conventional baghouse emission system where part of the fines was returned to the drum was part of the operation. The plant had five bins for virgin aggregates and three bins for RAP and RAS. The plant had three insulated silos with a capacity of 250 tons each and three others with capacity of 200 tons each. The capacity of the binder storage tank at the asphalt plant was 25,000 gallons. The RAP and RAS were added with the hot aggregate just outside the drying drum before they entered into the mixing drum. The recycling agent (T2) and the warm mix additive were injected to the asphalt binder line, and blend was directly injected to the mixing drum. Figure E.8 shows the pump and regulator to inject the recycling agent and warm mix into asphalt binder line. Two representatives from the recycling agent and warm mix additive suppliers were on-site during the production of the mixtures. The temperature of the binder in the storage tanks was maintained at 300°F. Both the warm mix additive and the recycling agent were stored and pumped into the binder line at ambient temperature. Figure E.7: Overview of the Asphalt Plant at Wilmington, Delaware.
E-8 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Figure E.8: Injection System of the Warm Mix Additive and Recycling Agent to the Binder Line and Pump to Regulate Rate. E.3 MIX PRODUCTION AND PAVING All three mixtures were produced and paved on the same day. All three mixtures were produced at 310°F. Ambient temperature was in the lower 40°F in the early morning and in the lower 50°F in the afternoon. Wind was flowing at 15 to 20 mph. The average duration of the mixture storage in the silo was approximately one hour. Sample collection began after production of 100 tons of mix for each test section. Production of control began at 7 am local time on December 02, 2016. Approximately 400 tons of control mix was produced at 350 tons/hour capacity. After the control mix, the T2 mix was produced with approximately 400 tons. Finally, the plant produced the T2 plus warm mix additive mix with approximately 700 tons. Table E.2 summarizes the mixture production schedule, placement, and ambient temperatures during laydown for different mixes. Table E.2: Production, Paving and Ambient Temperatures. Section Mixture Date of Production Plant Mix Temp, °F Paving Temp, °F Ambient Temp, °F 1 Control Mix 12/02/2016 310 270 â 275 41 â 45 2 T2 12/02/2016 310 275 â 280 48 â 50 3 T2 plus warm mix additive 12/02/2016 310 275 â 283 50 â 51 This project was not set up with station number or mile markers. The research team used the mail box and electric pole to identify the limits of each test section. The Control mix (Section 1) was placed on the west bound lane starting just 70 feet west of Electric Pole TP DPRC 113 or 175 feet west of Mailbox 1065 (west end) and extended to 160 feet west of intersection with Liberty Street (east end). The T2 mix (Section 2) was placed on both westbound and eastbound lanes. This mix on westbound lane was only 160 feet long starting at the end of control section and ending at the project limit at east end (Liberty Street). This mix on eastbound lane started from 100 feet west
Delaware Construction Report E-9 of Mailbox 988 (east end) and ended at 80 feet west of Mail box 892 (or 140 feet east of Mailbox 893). The T2 plus warm mix additive mix (Section 3) was placed on westbound lane starting where the T2 mix (Section 2) ended and extended to some part of Pole Bridge Road. Although this mix was placed on Pole Bridge, only the part on Port Penn Rd. is included in this project. Before laydown, the contractor applied a CSS1-h tack coat at rate of 0.045 gal/sq yd. Figure E.9 shows the application using a distributor truck. The tack coat application did not appear uniform or sufficient. The tack coat was applied at a temperature of 130°F. Figure E.9: Application of Tack Coat on Milled Surface. Figure E.10 through Figure E.12 show the laydown of mixture, compaction of material, and finished surface, respectively. The mixes were hauled to the job site using end-dump truck. The trucks had tarp to cover the mixes during transit. The trucks dumped the loose mix directly into the paver chute (Figure E.10). A shuttle buggy or other material transfer device was not used this project. The temperature behind the paver was measured using infrared temperature gun. The steel-wheel vibratory (breakdown) roller closely followed the paver. The compaction was achieved by three passes at vibrating mode by a roller, (Figure E.11 a), followed by three passes at static mode another roller (Figure E.11 b) of same size and weight. All 3 test mixtures were placed and compacted in a similar way.
E-10 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Figure E.10: Paving of the Surface Layer. (a) Vibratory Roller (b) Static Roller Figure E.11: Rollers Used During Compaction.
Delaware Construction Report E-11 E.4 SAMPLE COLLECTION Plant mix was collected from the trucks at plants by climbing on scaffolding (Figure E.13). Due to the demand from multiple research projects and universities involved, large amount of plant mix was collected in five-gallon buckets from multiple trucks. The plant mix samples were collected usually after 100 tons of production for any given section. The materials sampling scheme is listed in Table E.3. Figure E.12: Finished Pavement Surface.
E-12 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Table E.3: Materials Sampling Scheme. Sample Type Material Point of Sampling Lab-Mixed, Lab-Compacted Fine Aggregate Stockpile Coarse Aggregate Stockpile RAP Stockpile RAS Stockpile Rejuvenator Storage tank (plastic tote in metal cage) at plant PG 64-28 Asphalt Storage Tank Plant-Mixed, Lab-Compacted Loose Mix Truck at Plant detcapmoC Specimens Onsite Lab and DelDOT lab at Dover, DE. Plant-Mixed, Field- Compacted Road Cores Travel Lane (Center) With the help of the paving contractor, the research team also collected 24 six-inch diameter road cores from three test sections. Road cores were obtained from the center of the travel lane. Among these 24 cores, three of them (one from each of the test sections) were obtained at full depth asphalt layer to determine the existing pavement structure. All three full-depth cores showed similar pavement structure (Figure E.3). Figure E.14 through Figure E.17 show pictures of the RAP, RAS, and aggregate stockpiles.
Delaware Construction Report E-13 Figure E.13: Collection of Loose Plant Mix. Figure E.14: Primary RAP Stockpile.
E-14 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Figure E.15: RAS Stockpile. Figure E.16: Aggregate (one of several) Stockpile.
Delaware Construction Report E-15 Figure E.17: Aggregate (one of several) Stockpile.
