Technical, Economic and Environmental Evaluation of Warm Mix Asphalt and Coloured Asphalt for Usage in Canada

Transportation services play an important role in the Canadian economy, and social activities as well as Canada's competitiveness in the global economy. As one of the most valuable systems of transportation in Canada, 90 percent of all goods and services are transported via trucks over an extensive land area characterized by diverse landscapes and harsh environments. These unique characteristics of Canada, coupled with other challenges including an aging road network and highway infrastructure, limited finances, and environmental considerations provide great incentive to decision makers at federal, provincial/territorial, and municipal government levels to consider new and innovative ways to fund road transportation infrastructure. In an effort to evaluate two innovative pavement technologies applicable in both urban and rural areas, this research project is focused on (1) Coloured Hot Mix Asphalt (CHMA) and (2) Warm Mix Asphalt (WMA). The intent of the CHMA research study was to characterize the structural, functional, and environmental characteristics of the coloured asphalt design by analyzing laboratory and field performance. This research was focussed on providing innovative and sustainable solutions, which can be effectively used in Canada as means of ensuring durability and high performance throughout the material’s life cycle. To achieve the research objectives, materials collected during paving operations and materials produced under controlled laboratory conditions were systematically evaluated at CPATT to capture the impact of colouring pigment on the mixture’s strength. Results provided in this thesis suggest that pigmentation can adversely affect the performance and proper steps have to been taken to mitigate such effect: including using softer binder and lower Dust Proportion (DP) in the mixture. The state-of-the-art AASHTOWare Mechanistic-Empirical (M-E) Software was employed to complete the most accurate level of analysis, referred to as “Level 1”. ME analysis outputs were then used to develop prediction models for a design life of 50 years that can be used to establish Life Cycle Cost Analysis (LCCA). Based on LCCA analysis Bus Rapid Transit (BRT) lane structure surfaced with CHMA was found to be significantly more expensive to construct and maintain than a similar structure surfaced with HMA located in York Region. However, this cost difference is expected to decrease in near future as contractors are becoming more familiar with the mixture’s design and production techniques. This research further evaluated the performance of WMA technology by using different Performance-Graded Asphalt Cement (PGAC) sources modified with three types of WMA additives (Evotherm 3G, Rediset LQ, and SonneWarmix) in combination with two types of aggregate of pink granite and trap rock diabase. Results obtained in this comprehensive research were statistically analyzed to verify the significance of the results. All information collected from a combination of qualitative and quantitative laboratory test methods and M-E long-term prediction were then ranked in ascending order for each combination of aggregate, additive and binder type. This ranking suggests that certain warm mix technologies such as Evotherm 3G and Rediset LQ can be effectively used to lower the asphalt mixture production and construction temperatures, as well as improving the performance (i.e. moisture susceptibility) in both laboratory and field