Evaluation of Cold Central-Plant Recycling (CCPR) Technique Using Full-Scale Accelerated Pavement Testing
Two test pavement sections (four test cells) with cold central plant recycling (CCPR) as base layers were constructed at the Virginia Accelerated Pavement Testing facility to investigate the optimal overlay thickness on CCPR base layer in 2015. The two te
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Virginia Tech Transportation Institute, Blacksburg, USA {flintsch,wenjingx}@vt.edu Virginia Transportation Research Council, Charlottesville, USA [email protected] 3 Virginia Tech, Blacksburg, USA [email protected]
Abstract. Two test pavement sections (four test cells) with cold central plant recycling (CCPR) as base layers were constructed at the Virginia Accelerated Pavement Testing facility to investigate the optimal overlay thickness on CCPR base layer in 2015. The two test sections had similar structures but different thicknesses of surface layer: 76 mm and 38 mm (3 and 1.5 in.). Pavement sections were instrumented with strain gauges and pressure cells. The strain and pressure responses were collected and analyzed. By comparing the pressure distributions at different depths, it was found that the pressure in subbase of lane 2 is much higher than that in lane 1 because of the thinner surface layer. The distribution of pressure versus depth showed that the thinner surface layer led to a steeper reduction of pressure in surface and CCPR layers, which could mean increased rutting over time. Keywords: Cold central-plant recycling Dynamic response Pavement section
Accelerated pavement testing
1 Introduction Pavement recycling techniques include hot in-place recycling, cold recycling, and fulldepth reclamation (FDR). Cold recycling techniques, include cold in-place recycling (CIR) and cold central-plant recycling (CCPR), have attracted interest because of their documented cost and environmental benefits. A study by Liu et al. in 2014 (Liu et al. 2014) noted that using CCPR and CIR could reduce gas emissions significantly compared to hot mix asphalt (HMA). Cold recycling techniques have not commonly been used on primary roads in the United States because of the uncertainty of their long-term performance (Thompson et al. 2009; Stroup-Gardiner 2011). Virginia Department of Transportation (VDOT) has initiated many research projects to explore the performance of cold recycling techniques. Apeagyei and Diefenderfer (2012) used FDR, CIR, and CCPR together in the rehabilitation of a 6 km (3.7 mi) two-lane section of southbound Interstate 81 in Augusta County, Virginia. In © Springer Nature Switzerland AG 2020 A. Chabot et al. (Eds.): Accelerated Pavement Testing to Transport Infrastructure Innovation, LNCE 96, pp. 270–279, 2020. https://doi.org/10.1007/978-3-030-55236-7_28
Evaluation of Cold Central-Plant Recycling (CCPR) Technique
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2016, Diefenderfer et al. (2016) found that CCPR, CIR, and FDR recycling mixtures had a similar range of dynamic modulus values, and CCPR and CIR had a greater stiffness temperature dependency than that of FDR. After observing promising results from the I-81 project, VDOT developed a companion study to optimize surfacing thickness on CCPR layers by sponsoring the construction of three test sections at the National Center for Asphalt Technology (NCAT) (Timm et al. 2015). Each section featured a stone-matrix asphalt surface and Superpave dense-graded asphalt concret
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