Evaluation of Rutting, Cracking, and Fatigue Characteristics of Unmodified and ABS-Modified HMA Mixtures Involving Calcium Carbonate and Blowdown Fillers

A carbon-sulfur by-product material called Blowdown (B) has recently been considered as a possible alternative to calcium carbonate (CaCO3) as a mineral filler. This article studied the impact of acrylonitrile-butadiene-styrene (ABS) polymer on dense-graded (DG) mixtures with two different types of filler: CaCO3 and B-waste, which is an alternative filler. Asphalt with a 40/50 paving grade was mixed with ABS in several proportions (0.5, 1.0, 1.5, and 2.0% by weight of asphalt). Physical and homogeneity tests were performed on asphalt binders that had been modified with and without ABS. This study involved the making of blowdown-DG mixtures with either unmodified or ABS-modified asphalt binders, and their performance was evaluated in comparison to the CaCO3-DG reference mixtures. The DG mixture had a B and CaCO3 proportion of 5% (by weight of aggregate). Both the unmodified and ABS-modified DG mixtures containing both fillers (B and CaCO3) were subjected to performance testing, such as rutting resistance, cracking resistance, fracture energy, the flexibility index, and the J-integral (fatigue parameter) using Kim and Semi-Circular Bending (SCB) Tests. A FA-mixture exhibited greater rutting resistance than a B- mixture, and a 1.5% ABS modified-CaCO3 mixture demonstrated greater resistance to rutting than a B-mixture containing 1% ABS, according to testing results examined by Minitab software using analysis of variance least significant difference (ANOVA LSD). Regarding SCB parameters, the results showed noticeable enhancement for ABS-modified mixtures containing both fillers. Likewise, the results showed that the dosage of ABS needed for the B-mixture was less (1%) than that of the CaCO3 mixture (1.5%), indicating that the B-mixture is a more economical and environmentally friendly option for pavement applications.