Project title: Evaluation of warm-mix asphalt new technologies

0-5597During the first half of this research study, TxDOT had only placed 1000 tons of warm mix asphalt(WMA) as part of a demonstration project. By the end of this three year study, TxDOT had placed morethan 1,000,000 tons of WMA and allowed its use in all dense-graded mixtures through the implementationof a special provision 341---020. This research project was focused on evaluating all aspects of WMA andidentifying the effects of WMA technologies on mixture design, lab performance characteristics, and fieldperformance. An ongoing implementation study is underway to continue to monitor performance of WMAfield sections.Researchers found that WMA technologies improve the compactability of mixtures which can lead to areduction in design asphalt content if incorporated in the mixture design process. Laboratory tests indicatethat warm mix asphalt is initially less stiff than hot mix but stiffens considerably during the first year ofservice and with increases in laboratory oven curing time/temperature. Field performance of warm mixprojects has, thus far, been comparable to hot mix projects. X-ray CT and ground penetrating radar testingindicate the uniformity of WMA construction may be better than that for hot mix construction