Indirect performance comparison for styrene–butadiene–styrene polymer and fatty amine anti-strip modified asphalt mixtures

Abstract

Rutting and moisture damage are two important distress mechanisms for asphalt mixtures. The aim of this study is to analyze effects of SBS polymer and fatty amine anti-stripping agent additives for asphalt mixtures. Indirect performance comparison was evaluated with such additives. SBS and amine agents were compared with indirect effects in context with deformation and moisture resistance. Three types of moisture conditioning were selected. Regimes were based on water immersion, freeze–thaw cycles and superposition of these. Repeated creep tests (RCTs) and indirect tensile (ITT) tests were applied. In view of RCT polymer showed higher resistance to rutting based on permanent deformations than the control and amine modified mixtures. Lower deformations were calculated with SBS than the others according to the RCT. For high temperature and combined moisture effects based on water saturation and freeze–thaw cycle rutting and moisture problem have been being a serious problem for both control and SBS-anti stripping agent modified mixtures. In this context great importance must be given in design and quality control. Proportional moisture damage evaluation was found as a confliction. With the increasing of rise period lower resilient modulus (RM) were obtained with all control and modified mixtures in ITT. Selected moisture conditioning methods reveal observable level of damage with the RM test (ASTM D4123) with the selected parameters. Both amine and SBS modified mixtures gives higher RM hence load spreading capacity increases with both SBS and anti-strips.