Performance of recycled concrete aggregate pavements based on historical condition data

Abstract

ABSTRACTThe principles of sustainability dictate that construction materials should be recycled whenever possible. In the US, it is a common practice to crush old concrete pavements at the end of their service lives into recycled concrete aggregate (RCA) for use in the base course of new pavements but not to use the RCA in the new concrete pavement layer itself. In the 1980s, a number of trial projects were built in the US; however, their performance has never been evaluated quantitatively against that of similar conventional concrete pavements. In this paper, the performance of trial sections built in Minnesota were compared to that of their conventional counterparts. Such a study was necessary to evaluate the sustainability of using RCA in the concrete pavement. Analysis techniques employed included triple exponential smoothing, autoregressive integrated moving average, artificial neural network and Markov models. The mean time to reach a condition requiring a major CPR was found to be 27 years for the RCA pavements and 32 years for the non-RCA pavements. Despite this fact, it is possible to make the use of RCA in new concrete economically viable and sustainable. A lifecycle cost analysis over a 40 year time period showed the pavements with 100% coarse RCA to be cheaper at $1.10 per m2 compared to the conventional concrete.