Lessons Learnt from Accelerated Pavement Testing of Full-Depth Recycled Material Stabilized with Portland Cement
Accelerated pavement testing of full-depth recycled material stabilized with portland cement (FDR-PC) was recently completed at the University of California Pavement Research Center (UCPRC). The goal of the experiment was to develop guidelines and mechani
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Abstract. Accelerated pavement testing of full-depth recycled material stabilized with portland cement (FDR-PC) was recently completed at the University of California Pavement Research Center (UCPRC). The goal of the experiment was to develop guidelines and mechanistic-empirical models for in-place pavement recycling in California. A four-lane test track, each lane with a different recycling strategy, was constructed. Recycling depth was 250 mm and the FDR-PC lane had a design seven-day unconfined compressive strength (UCS) of 3.1 MPa. Heavy Vehicle Simulator testing followed a conventional UCPRC test plan, with all testing done at a constant temperature of 30 °C at 50 mm pavement depth, and one test done in the dry state, and a second test done wet. Post-test forensic investigation of the FDR-PC layer revealed extensive cracking in both wet and dry sections, attributed to a combination of material, environmental, and trafficking effects. The locations of the cracks correlated with structural deterioration assessed using backcalculated stiffness from falling weight and road surface deflectometer test results. The results emphasized the difference in structural capacities of the FDR-PC layer in areas with drying shrinkage and fatigue cracks compared to areas without these. The study findings also highlighted potential challenges in selecting representative test sections on pavements with cement stabilized layers and emphasized the importance of forensic investigations. Keywords: In-place recycling testing
Cement stabilization Accelerated pavement
1 Introduction Full-depth recycling/reclamation (FDR) of damaged asphalt concrete pavement to provide an improved base for a new asphalt concrete wearing course is a pavement rehabilitation strategy of increasing interest worldwide. FDR offers a rapid rehabilitation process, with minimal disruption to traffic. Most importantly, it reuses the aggregates already in the pavement, thereby minimizing the environmental, economic, and social impacts associated with extraction and transport of new aggregates. The California Department of Transportation (Caltrans) built its first pilot FDR project in 2001. Based on early apparent advantages of using this technology, Caltrans approved a comprehensive phased University of California Pavement Research Center (UCPRC) © Springer Nature Switzerland AG 2020 A. Chabot et al. (Eds.): Accelerated Pavement Testing to Transport Infrastructure Innovation, LNCE 96, pp. 309–318, 2020. https://doi.org/10.1007/978-3-030-55236-7_32
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study in 2004 to investigate the use of this technology under California pavement, material, traffic, and environmental conditions, with a special focus on the rehabilitation of thick, severely cracked asphalt pavements (Jones et al. 2008). Phase 2 of the study focused on accelerated pavement testing (APT) with the objective of understanding the mechanistic behavior of four different FDR stabilization strategies, namely unstabilized, foamed asphalt, asphalt emulsion, and portland cement (Jones et al.
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