Evaluation of Warm Mix Additives for Use in Modified Asphalt Mixtures
AdvisorSebaaly, Peter E.
Civil and Environmental Engineering
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The purpose of this research effort was to evaluate the use of warm-mix additives with modified (polymer-modified and terminal blend tire rubber) asphalt mixtures from Nevada and California. This research was completed in two stages: Sasobit and Advera were evaluated in first stage while Evotherm and Foaming were evaluated in second stage. The three main components of the experimental plan include: evaluation of mixture resistivity to moisture damage, pavement performance characteristics of the mixtures, and mechanistic analysis of the mixtures for simulated flexible pavement. The moisture resistivity of all mixtures were checked by Indirect Tensile Strength (ITS), and Dynamic Modulus (E*) tests. Dynamic Modulus Ratio (ECR) and Tensile Strength Ratio (TSR) were computed at multiple Freeze-Thaw (F-T) cycles for further evaluation of moisture sensitivity of mixtures. Flow Number (FN) and Flexural beam fatigue tests were conducted to evaluate the performance characteristics of WMA additives/technology.The terminal blend tire rubber-modified binder with lime treatment works effectively in resisting moisture damage, rutting, and to significantly-reasonably improve the fatigue life of the WMA Evotherm, Foaming, Advera and Sasobit mixtures. Hence, it is the best solution for the design and construction of sustainable asphalt pavements. The use of terminal blend rubberized asphalt binder is an excellent and economical selection in reducing tire waste and environmental impacts.