Influence of Production Temperature and Aggregate Moisture Content on the Performance of Warm Mix Asphalt (WMA)

摘要

The concept and use of warm mix asphalt (WMA) is becoming more popular in the asphaltindustry. The promise of reduced energy consumption, reduced emissions, and a more workableproduct is very appealing to an industry pressured by environmentalists with sustainabilityagendas and state agencies applying pay adjustments based on ride quality and pavement density.However, the use of WMA may come with some potential issues as well. Lower productiontemperatures may result in softer asphalt due to the reduced oxidative aging. While poorly driedaggregates may create issue with moisture damage.To evaluate these issues, a research project was undertaken to quantify the influence ofmixing (production) temperature on the rutting and fatigue cracking performance of WMAmixtures. Stripping potential was also evaluated using pre-wetted aggregate blends andmodifying the mixing procedure in the laboratory to more appropriately simulate a drum plantproduction of WMA. The laboratory procedure clearly indicated a decrease in rutting resistanceand stiffness when evaluated in the Asphalt Mixture Performance Tester (AMPT) and dryHamburg Wheel Tracking tests when mixing temperatures decreased. Meanwhile, fatiguecracking resistance increased in the Overlay Tester. Tensile Strength Ratio (TSR) and wetHamburg Wheel Tracking tests indicated that TSR and Hamburg rutting values were only able toobtain “passing” results at conventional hot mix asphalt mixing temperatures and with dryaggregates. The information presented may help state agencies in developing quality controltesting plans for future implementation of WMA.