Performance and temperature reduction evaluation of different warm mix asphalt technologies

Abstract

The reduction of the mixing and working temperatures obtained by using Warm Mix Asphalt (WMA) technologies in comparison with traditional Hot Mix Asphalts (HMA) can present many social, environmental and technological advantages. In order to guarantee these advantages during the life cycle of the pavement, WMA mixtures must have a good durability, similar to that obtained with equivalent HMA mixtures. The main objective of this paper is the study of different WMA technologies in order to determine their maximum temperature reduction, based on compactability considerations, and the consequent relative performance and durability of those WMA vs. HMA mixtures. After selecting different WMA technologies, namely using the two-phase mixing process with emulsions and bitumens, wax additives and surfactants, compactability tests were carried out according to EN 12697-10 in order to evaluate the temperature reduction. Then, performance tests, including indirect tensile strength, water sensitivity, wheel tracking, and stiffness tests were carried out on the selected mixtures and their results were ranked and compared to equivalent conventional HMA test results. The results of this study could be used as a guide on the selection of the WMA technologies suited to be applied on the field, in each specific case.