The influence of using hybrid polymers, aggregate gradation and fillers on moisture sensitivity of asphaltic mixtures

Abstract

Abstract Moisture damage can be defined as the loss of strength of asphaltic mixtures that resulted from the presence of water. The main objectives of this research is to investigate the influence of using hybrid elastomer and plastomer polymers modifiers, aggregate gradations and mineral fillers on moisture resistance of asphalt concrete mixture. In this study, 1% and 3% of plastomer Polyvinyl Chloride (PVC) were added for both pure asphalt binder and asphalt modified with 3% of elastomer Styrene Butadiene Styrene (SBS) to form hybrid polymers. Two types of mineral fillers were used: portland cement and limestone dust with two types of aggregate gradations: fine and coarse. A Humboldt Machine was used to measure the maximum load which makes the specimens completely fractures and then to estimate the Tensile Strength Ratio (TSR). The results of the study depict that the hybrid polymers improve the tensile strength ratio. This give an indication that hybrid polymers have great effect on improving the performance of modified asphalt binder. Also, results show that hybrid polymers improve the properties of flexible pavement against moisture damage and as a result increasing the durability and the service life of the pavements. According to that, it is concluded that modifying asphalt with hybrid polymers is more preferable to be used as anti-striping. Furthermore, it is deduced that fine gradation mixtures is more resistance than coarse mixtures to moisture damage. It is also recommended to use portland cement instead of limestone dust as mineral filler material in HMA.