Shear properties of waste glass-asphalt mastics

Abstract

This study aimed at using waste glass to improve shear properties of asphalt binders. Asphalt-glass mastics were prepared at four glass/asphalt (G/A) ratios: 0.05, 0.10, 0.20, and 0.30 by volume of asphalt. The Superpave dynamic shear rheometer (DSR) was used to measure the complex shear modulus value (∣G*∣) and phase angle (δ) for the control asphalt binder and the glass-asphalt mastics using frequency sweep tests conducted at nine loading frequencies: 10, 5.0, 3.0, 1.78, 1.0, 0.5, 0.3, 0.178, and 0.1 Hz and at a wide range of temperatures: 10, 20, 30, 40, 50, 60, and 70°C. Findings of the study showed that the waste glass filler improved ∣G*∣/cos δ (elastic part), ∣G*∣sin δ (fatigue parameter), and ∣G*∣/sin δ (rutting parameter) of the asphalt binder by decreasing δ and increasing ∣G*∣ especially at lower temperatures and high frequencies. Consequently, this enhanced the rutting and fatigue resistance of asphalt binders and improved the Superpave high temperature performance grade. It was also found that the increase in the ratio of the mix to the control asphalt binder for any of these parameters and the decrease in the phase angle ratio of the mix to the control asphalt binder were statistically significant (using 0.05 significance level) at 0.30 G/A ratio. Hence, the glass can be mixed in practice with the asphalt binder to increase its stiffness and therefore the rutting resistance and to improve the asphalt binder’s elastic part as a result of the decrease in the phase angle, which will improve the fatigue resistance.