Variation of Asphalt Requirement and Strength Properties among Hot Mix (HMA) and Warm Mix (WMA) Asphalt Concrete

Abstract

Due to the restrictions for protecting the environment, and the requirements to reduce fuel consumption, research work was started globally for verifying the possibility of implementation of warm mix asphalt (WMA) in pavement construction. Warm mix asphalt enables the production and compaction of asphalt concrete mixtures at temperatures (20-30 °C) lower than that of traditional hot mix asphalt (HMA). In this investigation, two WMA mixtures have been prepared in the laboratory using medium curing cutback (MC-30) and Cationic emulsion. HMA mixture was also prepared for comparison. Marshall specimens of (101.6 mm) in diameter and (63.5 mm) in height were constructed form the mixtures and subjected to indirect tensile strength (ITS) test, Marshall Stability, flow and volumetric properties determination. Test results were analyzed and compared. It was concluded that the stability of WMA is higher than HMA by 17 % and 47.87 % for (cutback and emulsified asphalt) WMA respectively, while the WMA exhibit lower flow than HMA by 34.67 % and 1.33 % when using (cutback and emulsion) WMA respectively. The optimum asphalt content was (20.69 and 32.35) % higher for (cutback and emulsion) WMA than that of HMA. The (ITS) at 25 ⁰C decreases by (28.58 and 4.51) % when the asphalt content increased and decreased by 0.5 % from optimum asphalt content (OAC) for WMA- emulsion asphalt.