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.
C-1 A P P E N D I X C Indiana Construction Report La Porte County executed the reconstruction of CO Road W2100 South in the fall of 2015. This field project, located in north-central part of Indiana, consisted of a 2.8 mile-long binder course and asphalt overlay placement. Three sections were placed on the eastbound lane between County Road South 875W and County Road South 600W near the town of La Crosse, IN to evaluate the effect of a softer virgin binder and a recycling agent on the performance of an asphalt mixture with high RAP and RAS content. Details of sections included in the field project are listed in Table C.1. Figure C.1 shows the layout of the sections. Note that the remaining surface course was paved with the control mix. The overlay and binder course were paved in the first week of September 2015. Table C.1: Indiana Field Project Sections Section No. Section Name Description Additive/Rejuvenator Dosage A/Nrednib22-46GPnigriV1 2 Evoflex 16% RAP + 8% MWAS + PG 58-28 binder 3% Evoflex rejuvenator by weight of total asphalt content 3 Control 28% RAP + 2% MWAS + PG 58-28 binder N/A CO Road W2100 South is a two-way undivided rural road located in the south side of La Porte County in Indiana. La Porte County itself is located in the north-central part of Indiana bordering Lake Michigan. The typical roadbed width was 26 ft., including two 11-ft. travel lanes (paved) and 2-ft. unpaved shoulder on each side. The portion of the road where the field project is located is straight without intersections and with few driveways. The traffic is low and consists of occasional farm equipment. The reconstruction of this field project included a 1.5 in. binder course (19mm Superpave mix), followed by a 1.5 in. surface course (9.5 mm Superpave mix). The existing pavement, which consisted of a seal coat on top of a gravel/dirt road, was in poor condition. Figure C.2 shows a portion of the field project where the left lane was paved with the binder course and the right lane had the original pavement surface. Figure C.3 also depicts the existing pavement surface on another portion of the field project. As can be seen in Figure C.2 and Figure C.3, the entire pavement had numerous potholes and large areas where the seal coat was missing.
C-2 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Figure C.1: Sections Layout for the Indiana field project. Figure C.2: Binder course and existing pavement surface at the Indiana field project.
Indiana Construction Report C-3 Figure C.3: Existing pavement surface at the Indiana field project. C.1 MATERIALS AND MIXTURES All three mixes were designed using the 9.5 mm Superpave Mix Cat 2/ Type B surface mix with 75 Superpave gyrations following the Indiana Department of Transportation specifications. Two virgin binders (i.e., PG 64-22 and PG 58-28) were used. Aggregates including limestone and slug from blast furnace from multiple sources were also employed. The source of RAP is unknown. RAS was produced by shredding and grinding manufacturerâs waste shingles. Shingles were shredded on-site at the asphalt mix plant. The shingles were 100% passing the 3/8-in. sieve. Samples of the stockpiles of aggregate and RAS materials available at the asphalt mix plant are illustrated in Figure C.4 and Figure C.5. Figure C.6, Figure C.7, and Figure C.8 present the mix designs used in this field project.
C-4 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Figure C.4: One of several aggregate stockpiles. Figure C.5: RAP stockpile.
Figure C.6: Summary of virgin mix design.
Figure C.7: Summary of T2 mix design.
Figure C.8: Summary of control mix design.
C-8 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Figure C.9: Overview of asphalt mix plant at La Porte, Indiana. During production, the RAP and RAS materials were added along with the heated aggregate just outside the drying drum, before entering the mixing drum. The binder was directly injected into the mixing drum. The recycling agent was injected via pump and regulator to the binder line (Figure C.10). The plant produced at a typical rate of 200 to 250 tons per hour during the construction of the field project. Table C.2 summarizes the production, placement, and ambient temperatures during laydown. Table C.2: Production, Paving and Ambient Temperatures for the Indiana Field Project Section Mix Date of Production Plant Mix Temp, °F Paving Temp, °F Ambient Temp, °F 1 Virgin 09/04/2015 310-315 260 - 270 70 - 75 2 T2 09/04/2015 295-300 260 - 272 75 - 80 3 Control 09/04/2015 295-300 265 - 280 80 - 82
Indiana Construction Report C-9 Figure C.10: Recycling agent injected to the binder line (left) and pump used to regulate the recycling agent dosage (right). C.2 MIX PRODUCTION All mixes were produced and paved on the same day. Production of the virgin mix began at 6 am local time on September 4, 2015. Approximately 200 tons of virgin mix was produced at 200 tons/hour capacity. The virgin mix was produced at 315°F. Ambient temperature was in lower 70s in the early morning and in lower 80s in the afternoon. There was little or no wind until late in the afternoon. Sample collection began after production of 85 tons of virgin mix. The virgin mix was produced first, followed by the T2 mix. Approximately 630 tons of the T2 mix was produced, although the first 30 to 35 tons did not include the recycling agent. T2 was added at 3 percent by weight of total asphalt content. Sample collection began after production of 143 tons of the T2 mix. The T2 mix was produced at 300°F. Three representatives from the recycling agent supplier were present during the production of this mix to assure proper application of the T2. Soon after finishing the production of the T2 mix, the asphalt mix plant started producing the control mix. Until the end of the day, approximately 600 tons of control mix was produced. Note that the remainder of the CO Road W2100 was paved with the control mix. C.3 PAVING OPERATIONS Before placement of binder course and surface course, the contractor applied a rapid set tack coat with shot rate of 0.08 gal/yd2 and 0.06 gal/yd2, respectively. All mixes were hauled to the job site using end-dump truck with tarp covers. The virgin mix was placed on the eastbound lane starting just 200 ft. east of railway crossing to Mailbox 7858; the length of the virgin section was approximately 0.43 miles. The trucks dumped the loose mix directly into the paver chute as shown in Figure C.11. A shuttle buggy or any other material transfer device was not employed during construction. An infrared temperature gun was used to measure the temperature behind the paver.
C-10 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Figure C.11: Paving of the surface layer at the Indiana field project. Placement of the T2 mix started near the Mailbox 7858 and continued for approximately 1.25 miles. The first 300 ft. of this section did not include the recycling agent in the mix. The control mix test section began at the end of T2 mix section, approximately 0.53 miles from County Road S600W. A steel-wheel vibratory (breakdown) roller followed closely the paver shown in Figure C.12. The compaction was achieved by four passes on vibrating mode, and two passes on static mode (Figure C.13 a), followed by three passes at vibrating mode and two passes at static mode by a separate roller (Figure C.13 b), and then several passes of static steel finish roller (Figure C.13 c). All mixes were placed and compacted in the same way. No visible sign of segregation was noticed on the sections.
Indiana Construction Report C-11 Figure C.12: Paver used for laydown at the Indiana field project. (a) Vibratory Roller 1 (b) Vibratory Roller 2 (c) Finish Roller Figure C.13: Rollers used for compaction at the Indiana field project. Quality control reports noted 90 percent density achievement in the field. Figure C.14 and Figure C.15 present the quality control results from the T2 and Control test sections mixes, respectively. The contractor could not provide the quality control results corresponding to the virgin mix.
C-12 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Figure C.14: Quality control results for the T2 mix.
Indiana Construction Report C-13 Figure C.15: Quality control results for the control mix. C.4 SAMPLE COLLECTION Plant mix was collected from the dump trucks at the asphalt mix plant by climbing on scaffolding. Due to the large quantities of plant mix needed for research purposes, multiple dump trucks were sampled. The samples were collected after about 100 tons of production for each section. The material sampling scheme is listed in Table C.4. With the help of the paving contractor, the research team also collected 27 six-in. diameter field cores (Figure C.16) from the sections. The cores were obtained from the center of the eastbound travel lane.
C-14 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios Table C.4: Materials Sampling Scheme Sample Type Material Point of Sampling Lab-Mixed, Lab-Compacted Fine aggregate Stockpile Coarse aggregate Stockpile elipkcotSPAR elipkcotSSAR Recycling agent Storage tank (plastic tote in metal cage) at plant PG 64-22 binder Storage tank PG 58-28 binder Storage tank Plant-Mixed, Lab-Compacted Loose Mix Dump truck at plant Plant-Mixed, Field- Compacted Field Cores EB Travel Lane (Center) Figure C.16: Core with surface and binder layers
