This study focuses on determining the engineering characteristics of hot mix asphalt using mineral filler with asphaltite. Since asphaltite which consists of high amount of sulfur leads to air pollution when used as a heating material and also being hydrocarbon sourced, it seems better to use asphaltite in the hot mix asphalts. The hot mix asphalts in this study were prepared by using 25%, 50%, 75%, and 100% mixing ratios based on the mineral filler ratio to analyze the possibility of using asphaltite. The results reveal that using asphaltite as a whole filler significantly increased the retained Marshall stability by 27% and increased the stiffness modulus by 91% at 15°C. As for the tensile strength test, it was determined that the control mixtures lost 35% of its tensile strength ratio after one freeze-thaw cycle, however the mixtures containing completely asphaltite as filler lost only 13%. A remarkable increase was found at fatigue test. The cycle number leading to failure of the mixtures containing 25%, 50%, 75% and 100% asphaltite by weight of filler were 2.9, 3.6, 5.4 and 7.9 times greater than those of the control mixtures respectively at 300 kPa stress level. Using asphaltite as filler exhibited high performance by improving especially the resistance to moisture damage and fatigue life.
This article presents a laboratory evaluation of conventional, fundamental, rheological, and morphological characteristics of styrene-butadiene-styrene (SBS) and ethylene vinyl acetate (EVA) polymer modified bitumens. Polymer modified bitumen (PMB) samples have been produced by mixing a 50/70 penetration grade unmodified (base) bitumen with SBS and EVA copolymer at different polymer contents. The fundamental viscoelastic properties of the PMBs were determined using dynamic (oscillatory) mechanical analysis and presented in the form of temperature and frequency-dependent rheological parameters. The morphology of the samples as well as the percent area distribution of polymers throughout the base bitumen have been characterized and determined by means of fluorescent light optic microscopy and Qwin Plus image analysis software, respectively. The results indicated that polymer modification improved the conventional and rheological properties of the base bitumen. It was also concluded that the temperature and frequency had a significant effect on complex modulus of PMBs. The behavior of EVA and SBS PMBs had exhibited quite difference at 50 C. Moreover, it was found out that at low polymer contents, the samples revealed the existence of dispersed polymer particles in a continuous bitumen phase, whereas at high polymer contents a continuous polymer phase has been observed.
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