Evaluation of the effect of carbon nano tube on water damage resistance of Stone matrix asphalt mixtures containing polyphosphoric acid and styrene butadiene rubber

Abstract

The current study assessed the influence of Poly Phosphoric Acid (PPA), Carbon Nano Tube (CNT), and Styrene Butadiene Rubber (SBR) additive on moisture susceptibility of SMA samples. Two types of original binder (AC-60/70, AC-85/100) were used. In this research, to modify original binders, CNT (0%, 0.5%, 1%, 1.5%, and 2% by weight of binder), PPA (0.5% by weight of binder) and SBR (2% by weight of binder) were used. For this purpose, softening point, penetration and, Dynamic Shear Rheometer tests were implemented to evaluate the performance of different binders. Also, the storage stability test and resistance of binders against aging were evaluated. To investigate the moisture sensitivity of modified mixtures, four different methods were used, such as; Resilient Modulus Ratio (RMR), Fracture Energy Ratio (FER), Tensile Strength Ratio (TSR), and Texas boiling test. To analyze the data, two-factor analysis of variance (ANOVA) was investigated. Results indicated that the utilization of SBR/PPA enhances the Resilient Modulus (Mr), Indirect Tensile Strength (ITS), Fracture Energy (FE) of mixtures. By increasing the CNT percentage, the ITS, Mr, and fracture energy of mixtures enhance. While, the TSR, RMR, and FER of mixtures increase up to 1.5% CNT, and by addition of more CNT, the mentioned parameters decreased.