Cracking resistance of polypropylene fiber–reinforced cold mix asphalt incorporating stone waste fillers

This study aims to evaluate the cracking resistance of polypropylene (PP) fiber–reinforced cold mix asphalt (CMA) incorporating marble dust (MD) and sandstone dust (SD) as partial (2 %, 4 %) and full (6 %) replacements for the conventional filler, granite dust (GD). Specimens were cured at 40 °C for 3, 7, and 14 days to assess the effect of curing duration on CMA's cracking behavior. Mixture properties were first evaluated using Indirect Tensile Strength (ITS) and Tensile Strength Ratio (TSR), followed by the Indirect Tensile Asphalt Cracking Test (IDEAL-CT) to quantify cracking resistance through the cracking tolerance index (CT<inf>index</inf>) and cracking brittleness index (CB<inf>index</inf>). Furthermore, grey relational analysis (GRA) was used to evaluate the relative influence of filler type, curing duration, and conditioning on the cracking behaviour of the mix. ITS results showed strength gains of 17.6 % and 58.6 % at 7 and 14 days of curing, respectively, compared to 3 days of curing, while full filler replacement exhibited reduced moisture resistance. IDEAL-CT indicated increases in fracture energy (G<inf>f</inf>) by 16.3 % and 51.6 %, and strain tolerance index (l<inf>75</inf>) by 15.5 % and 9.1 %, over the curing periods of 3–7 and 3–14 days, respectively. CT<inf>index</inf> ranged from 500 to 1000 for dry-conditioned specimens and 1000–2000 for wet-conditioned samples, while CB<inf>index</inf> decreased from 400 to 700 under dry conditions to 100–400 for wet mixes. GRA confirmed curing duration as the most influential factor, while filler type had minimal effect (Δ ≤ 0.086). Overall, extending the curing time enhanced the cracking resistance, with moderate filler replacement providing the optimal balance between strength and durability. © 2025 Elsevier Ltd