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Material Properties of Cold In-Place Recycled and Full-Depth Reclamation Asphalt Concrete (2017)

Chapter: Chapter 2 - Projects and Materials Investigated

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Suggested Citation:"Chapter 2 - Projects and Materials Investigated." National Academies of Sciences, Engineering, and Medicine. 2017. Material Properties of Cold In-Place Recycled and Full-Depth Reclamation Asphalt Concrete. Washington, DC: The National Academies Press. doi: 10.17226/24902.
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Suggested Citation:"Chapter 2 - Projects and Materials Investigated." National Academies of Sciences, Engineering, and Medicine. 2017. Material Properties of Cold In-Place Recycled and Full-Depth Reclamation Asphalt Concrete. Washington, DC: The National Academies Press. doi: 10.17226/24902.
×
Page 9
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Suggested Citation:"Chapter 2 - Projects and Materials Investigated." National Academies of Sciences, Engineering, and Medicine. 2017. Material Properties of Cold In-Place Recycled and Full-Depth Reclamation Asphalt Concrete. Washington, DC: The National Academies Press. doi: 10.17226/24902.
×
Page 10
Page 11
Suggested Citation:"Chapter 2 - Projects and Materials Investigated." National Academies of Sciences, Engineering, and Medicine. 2017. Material Properties of Cold In-Place Recycled and Full-Depth Reclamation Asphalt Concrete. Washington, DC: The National Academies Press. doi: 10.17226/24902.
×
Page 11
Page 12
Suggested Citation:"Chapter 2 - Projects and Materials Investigated." National Academies of Sciences, Engineering, and Medicine. 2017. Material Properties of Cold In-Place Recycled and Full-Depth Reclamation Asphalt Concrete. Washington, DC: The National Academies Press. doi: 10.17226/24902.
×
Page 12

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82.1 Description of Projects Cores were obtained from 27 projects located throughout the United States and Canada. Projects were selected for coring if the recycled layer was approximately 12–24 months old at the time of sampling and a mix design was available for the recycled layer. Originally, the project team sought projects that would fulfill a matrix of environmental conditions, recycling techniques, and recycling agents. During the course of the study, the project team found it dif- ficult to obtain cores from a sufficient number of projects to meet all the desired criteria of the project matrix. Consequently, the project team sought cores from as many projects as possible within the time frame of the study; however, cores from projects were only included that met the requirements of time since construction and availability of mix design. Figure 1 shows the distribution of projects and the recycling techniques. Not all the cores from projects identified in Figure 1 were used, as some were damaged during coring or shipment, or were unsuitable for other reasons. Table 1 provides a summary of the locations and types of recycled mixtures for each project. From the table it can be seen that 15 CIR, three CCPR, and six FDR projects were included. Among the CIR projects, three included foamed asphalt as a recycling agent while 12 included emulsified asphalt. Two of the CIR projects using foamed asphalt included no chemical additive, whereas one project included cement. Four of the CIR projects using emulsified asphalt included lime as a chemical additive, two projects included cement, and five projects included no chemical addi- tive. All three CCPR projects used emulsified asphalt as the recycling agent. Of these, two projects included cement as a chemical additive and the third used no chemical additive. Of the six FDR projects, four projects used foamed asphalt as the stabilizing agent and two projects used emulsified asphalt. All four of the FDR projects using foamed asphalt and one of the two FDR projects using emulsified asphalt included cement as a chemical additive. The other FDR project using emulsified asphalt included no chemical additive. 2.2 Description of Cores The project team sought cores from projects where a mix design was completed and where the volunteer agency had the ability to collect the cores. During the course of the study, between seven and ten 6-in. diameter cores were received from each of 26 projects. For all projects but one, the volunteer agency collected all cores and shipped them to the project team. The VTRC research team collected the cores from the CIR project in West Virginia. Most of the cores included all overlying surface layers, recycled layers, and underlying bound layers (if any existed). C H A P T E R 2 Projects and Materials Investigated

Projects and Materials Investigated 9 For shipping, the project team had suggested that each core be wrapped in plastic wrap, placed inside a 6-in. diameter concrete cylinder mold, cushioned in bubble wrap, and boxed. Most cores prepared in this way arrived undamaged from the shipping process and were suitable for testing. Figure 2 and Figure 3 show sample intact cores from two projects. Some cores from the projects in Illinois and New York (see Figure 1) were damaged during shipping and were not used for subsequent testing. As seen in Figures 2 and 3, the recycled layer on most cores was received in good condition. In some cases, where the recycled layer was at the bottom of the core, the full thickness of the recycled layer was not always retrieved. Figure 4 shows a core in which a portion of the bottom of the FDR layer (seen at the top of the photo) was not retrieved during the coring process. It is not possible to determine if this issue was caused by insufficient curing of the recycled layer or was an artifact of the coring process. Despite some missing material, such cores could be used to obtain test specimens provided sufficient material remained elsewhere within the core. Figure 5 shows an example of the surface layer separated from the recycled layer in a core from an FDR project from Edmonton, Alberta, Canada. It is not possible to tell if this separation was a construction defect or a result of the coring process, but if the core is representative of the entire project, the performance of this section certainly would be expected to be compromised. All eleven cores from this project had a debonded surface layer, suggesting that the issue was wide- spread. The debonded condition did not, however, affect the research team’s ability to obtain a test specimen for this project. Figure 1. Approximate locations of recycling projects.

10 Material Properties of Cold In-Place Recycled and Full-Depth Reclamation Asphalt Concrete Location Constr. Year Project ID Project Description (Road, city, town, or county) Type Primary Recycling Agent Chemical Additive Kansas 2012 13-1093 Scott County CIR Emulsion Lime Ontario 2012 13-1111 Highway 10/89 CIR Foam -- Ontario 2012 13-1112 Highway 21 (Tiverton to Port Elgin) CIR Foam -- Ontario 2012 13-1113 Highway 24 CIR Emulsion -- Ontario 2012 13-1114 Highway 21 (Amberley to Kincardine) CCR Emulsion -- Alberta 2012 13-1115 Dovercourt, 141 Street (Edmonton) FDR Foam Cement Alberta 2012 13-1116 Windsor Park 1, 92 Avenue (Edmonton) FDR Foam Cement Alberta 2012 13-1117 Windsor Park 2, 117 Street (Edmonton) FDR Foam Cement California 2012 13-1124 Redmond Avenue (San Jose) CIR Foam Cement Colorado 2012 13-1127 State Highway 83 CIR Emulsion Lime California 2012 14-1001 50th Street West (Los Angeles) CCPR Emulsion -- California 2012 14-1002 Vasquez Canyon Road (Los Angeles) CIR Emulsion Cement California 2012 14-1003 Altadena Drive (Los Angeles) CIR Emulsion -- West Virginia 2013 14-1011 Fort Martin Road CIR Emulsion Cement Delaware 2013 14-1025 Seashore Highway (Lewes to Georgetown) CIR Emulsion -- Delaware 2013 14-1026 Gravel Hill Road CIR Emulsion -- Delaware 2013 14-1027 Springfield Road FDR Emulsion -- Delaware 2013 14-1028 Sussex Pine Road FDR Emulsion Cement Utah 2013 14-1055 State Route 32 CCR Emulsion Lime Georgia 2012 14-1057 Kelly Mill Road FDR Foam Cement Washington State 2013 14-1058 State Route 14 CIR Emulsion Lime Colorado 2013 14-1062 State Highway 160 (Cortez) CCR Emulsion Lime Maine 2013 15-1001 (Lyman) CCPR Emulsion Cement Maine 2013 15-1002 (Corinna, Exeter) CCPR Emulsion Cement Table 1. Details of recycling projects.

Projects and Materials Investigated 11 Figure 2. Core obtained from FDR project in Delaware. Figure 3. Core obtained from CIR project in West Virginia.

12 Material Properties of Cold In-Place Recycled and Full-Depth Reclamation Asphalt Concrete Figure 4. Core from FDR project in Delaware showing missing portion of recycled layer. Figure 5. Core from FDR project in Edmonton showing a debonded surface layer.

Next: Chapter 3 - Specimen Preparation and Testing Methods »
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TRB's National Cooperative Highway Research Program (NCHRP) Research Report 863: Material Properties of Cold In-Place Recycled and Full-Depth Reclamation Asphalt Concrete presents procedures for determining material properties of cold-recycled asphalt mixtures for input to pavement structural design programs. Highway agencies are placing increasing emphasis on sustainability, recycling, and making maximum use of existing pavement assets in rehabilitation strategies. Such emphasis has led agencies to explore the advantages of producing asphalt mixtures using cold-recycling technology, particularly cold in-place recycling (CIR), cold central-plant recycling (CCPR), and full-depth reclamation (FDR).

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