The effect of nanomaterials as anti-stripping additives on the moisture sensitivity of glasphalt

Abstract

Despite the environmental and economic benefits of using glasphalt, it suffers from a number of disadvantages. The most common damage in glasphalt is the effect of water on bitumen-aggregate adhesion and the occurrence of moisture damage. One way to improve the resistance of glasphalt against the moisture damage is to use anti-stripping additives. Accordingly, the effect of two types of nanomaterials including nano hydrated lime (NHL) and nano calcium carbonate (NCC) as bitumen modifiers on the moisture sensitivity of glass asphalt has been investigated in this study. The moisture sensitivity of asphalt mixtures was assessed by the AASHTO T283 test and surface free energy (SFE) method. Indirect tensile strength (ITS) results show that the use of waste glass cullet increases and decreases the resistance of asphalt mixture in dry and wet conditions, respectively. An increase in the number of freeze–thaw cycles causes a decrease in the ITS of the glasphalt. The obtained results showed that using both nanomaterials in glasphalt significantly improved the resistance to moisture sensitivity. Bitumen modification using NHL and NCC, which was added in 2% bitumen, reduced the SFE of cohesion, which resulted in improving the bitumen coating on the aggregate surface and the adhesive between bitumen and aggregate.