Enhancing hot mix asphalt performance: A comparative analysis of cement and limestone fillers

Abstract

Pavements made from asphalt in hot climates, such as Iraq, are subjected to high heat and heavy traffic volume, causing accelerated damage by ruts, cracks, or moisture-related problems, causing pavements to have a reduced lifespan. The performance of Hot Mix Asphalt (HMA) is primarily affected by the type and quantity of filler used in its production. This experiment assessed Portland cement as an active filler and limestone powder as a less active filler at an additive rate of 4% and 8% of total aggregate weight. All mixtures were tested in the laboratory based on the Marshall mix design method, with specific mechanical and volumetric properties considered, including Marshall stability, flow, bulk density, air voids (Va), voids in mineral aggregate (VMA), voids filled with asphalt (VFA), and the Marshall Quotient (MQ). Increased application of filler at 8% vs. 4% provided an increase in stability of up to 15.6%, an increase in MQ of up to 50%, and a decrease in flow of up to 17.3%. All data indicate that the addition of 8% Portland cement provides the best overall stability and MQ, but it did not satisfy the SCRB specification of VMA, suggesting a need for slight modification to the aggregate gradation.