Effects of Reducing Asphalt Production Temperatures Using Warm Mix Technologies on Burner Fuel Consumption and Mixture Performance Properties

Abstract

This study evaluated the impact of using warm mix technologies (WMTs) to lower production temperatures on energy consumption and mixture performance characteristics. Two experiments were conducted using ALDOT-approved hot mix asphalt (HMA) designs. The first experiment compared two warm mix asphalt (WMA) mixtures, produced using chemical additives WMT1 and WMT2, with a control HMA mixture. The second experiment involved one control HMA mixture and one WMA mixture using WMT1 produced at multiple temperatures. Both experiments evaluated burner fuel consumption, intermediate cracking resistance using the Indirect Tensile Asphalt Cracking Test (IDEAL-CT) test, and rutting resistance using the Hamburg Wheel-Tracking Test (HWTT) and High-Temperature Indirect Tensile Test (HT-IDT). Experiment 1 used reheated plant-mixed, lab-compacted (RH-PMLC) and lab-mixed, lab-compacted (LMLC) specimens, while Experiment 2 used hot-compacted PMLC (H-PMLC) specimens. The results indicated that using WMTs at lower production temperatures can reduce energy consumption by approximately 20%, potentially lowering emissions. The cracking resistance of WMA mixtures was similar to that of the control HMA when using plant-mixed samples. However, significantly better cracking resistance was observed when using LMLC samples. Additionally, rutting and moisture resistance were comparable or reduced for WMA mixtures but still met the minimum rutting requirement. This study confirms that lowering the production temperature of WMA mixtures can reduce burner energy consumption and emissions without compromising mixture performance characteristics.