Laboratory evaluation of foamed warm mix binders and mixtures containing reclaimed asphalt pavements

Abstract

Concerns exist regarding whether residual foaming water will be unfavourable for the performance of asphalt and mixtures when foamed warm mix asphalt (FWMA) binders are combined with reclaimed asphalt pavement (RAP). A series of experimental methods was utilised to evaluate the performance of FWMA–RAP binders and mixtures. It was found that the FWMA–RAP binder performance was consistent with that of the mixtures. Foamed asphalts and mixtures exhibited better low-temperature performance and had longer fatigue lives than their unfoamed counterparts did at the same RAP content, but exhibited worse high-temperature performance and lower water stability. The RAP content had a significant influence on the asphalt and mixture performances and appeared to aggravate the effect of asphalt foaming. Foamed asphalt mixtures containing RAP were able to satisfy the standard requirements when the RAP content did not exceed 30%.