THE INFLUENCE OF RESIN MODIFIERS ON THE PERFORMANCE OF HOT MIX ASPHALT

Abstract

In order to study the influence of resin modifiers materials on the performance of hot mix asphalts (HMA), two types of resin modifiers were selected. One was anUnsaturated Polyester Resin (UPR) and the other was an Epoxy Resin (ER). Also, unsaturated polyester resin mixed with 3% epoxy resin (UPRER) was used according to test results, which gave preference to 3% additions. Marshal test was conducted to study the stability, flow, bulk density, air voids (AV), voids in mineral aggregate (VMA) and voids filled with bitumen (VFA) for controlled hot asphalt mixtures and resin: modified mixtures at various resin modifiers contents. A computer program named BISAR was also used to determine the total stress, strain and displacement in x-y, and z-direction for flexible pavements constructed with these hot mix asphalts modified with resin additives.Experimental results showed that all resin-modified asphalt mixtures have higher flow, bulk density and VFA compared with control mixture. The stability of asphalt mixtures with UPPER was always higher than the control mixture. Unlike, for type ER and UPR the stability was lower than the control mixture up to 1% and 2% respectively then they increase. The UPRER gave higher stability, flow, AV and VMA than the other types. Moreover, the UPR gave the highest value of bulk density and VFA. The maximum stability occurs at 3% resin modifiers content for all types. The total stress and strain relatively increase with the increase of mix depth till 10 cm, then they decrease for all types of resin modifiers. The maximum total stresses and strain in case of UPRER are higher values than those achieved by ER and UPR respectively. The total displacement in case of UPRER is higher than that achieved by ER and UPR respectively. As resin modifiers can improve the field performance of asphalt mixes comprehensively, they will be of great benefit to the engineering field.