Evaluation of the effectiveness of different warm mix technologies to improve moisture susceptibility of asphalt mixes

The Ministry of Transportation of Ontario (MTO) has implemented the use of Warm Mix Asphalt (WMA) technology on Ontario's highways and roads since 2008. Many Types of WMA technologies have been successfully used to produce and place close to one million tonnes of WMA in Ontario with proven environmental, economical and safety benefits. However, reduction in the production temperature and effects of some WMA additives have raised concerns with moisture resistance of WMA mixes. To address the aforementioned concern, MTO and the Centre for Pavement and Transportation Technology (CPATT) at the University of Waterloo have partnered under MTO's Highway Infrastructure Innovation Funding Program (HIIFP) to evaluate the moisture susceptibility of WMA through a laboratory testing program. The program includes Hamburg wheel rut testing, tensile strength ratio, and stripping by static immersion tests. Mixtures for this study are produced using two Performance Graded Asphalt Cement (PGAC) sources, three Types of WMA additives, and two aggregate Types. The selection of the materials was based on typical Superpave asphalt mixes used in Ontario. This paper presents the laboratory test results and evaluates the effects of several WMA additives on moisture resistance of typical Ontario Superpave mixes. The paper further attempts to determine any correlation between the results from the Hamburg test, TSR, and static immersion test.