Sensitivity Analysis of RAP Aggregate Properties on the Performance of Asphalt Emulsion Cold Recycled Mixes

Nowadays, asphalt emulsion cold recycled mixes has been used as binder course in the maintenance and rehabilitation projects of deteriorated asphalt pavements in Jiangsu province, China. The objective of this research was to conduct sensitivity analysis of RAP aggregate properties on the performance of cold recycling mixes based on five asphalt emulsion cold in-place recycling (CIR) projects in Jiangsu Province, China. Firstly, the aggregate properties of five RAP materials, such as sand equivalent, the percentage of flat and elongated particles, angularity and crushing value, were tested from the recovered RAP aggregates. Secondly, the properties of cold recycled mixes were evaluated based on Marshall tests and the indirect tensile strength tests with the same content of asphalt emulsion and cement under similar test conditions. Finally, the linear analysis and pseudo-inverse matrix method was performed to study the correlativity analysis between RAP aggregate properties and the performance of cold recycled mixes. The test results showed that different RAP material has a remarkable influence on the mixes performance. The results indicated that there was not good linear correlation relationship between RAP aggregates characteristics and the performance of recycled mixes, while the pseudo-inverse matrix method showed that the sensitive factors of four indexes of RAP aggregate properties on the performance of asphalt emulsion cold recycled mixes had the same primary and secondary impaction.