Investigation of the rutting potential of asphalt binder and mixture modified by styrene-ethylene/propylene-styrene nanocomposite

Abstract

Rutting failure is one of the major distresses in the flexible pavements, which is appeared due to the accumulation of permanent deformations in the pavement layers under traffic load. Specifications of consumed asphalt binder in hot mix asphalts are one of the effective factors on this type of failure. The increased traffic of heavy vehicles on roads leads to asphalt pavements containing pure asphalt binders insufficiently resistant to rutting failure. Hence, modified asphalt binders are utilized to lessen the probability of rutting occurrence in the asphalt mixtures. In this study, Styrene-ethylene/propylene-styrene (SEPS) nanocomposite was used as an asphalt binder modifier, and the rheological properties of asphalt binders were evaluated by employing dynamic shear rheometer (DSR) and multiple stress creep & recovery (MSCR) tests. Moreover, the rutting potential of asphalt mixtures were determined by conducting dynamic creep test at different temperatures. The results of DSR showed that the SEPS nanocomposite increased the rutting factor (G*/sinδ) which is demonstrative of less influence of the modified asphalt binder on permanent deformation due to higher stiffness and elastic characteristics of binder. Also, the results of the MSCR test revealed that the use of SEPS nanocomposites reduced the non-recoverable creep compliance and increased the percentage of recoverable strain in the modified asphalt binder. This propensity was further corroborated at higher temperature. Furthermore, the results of the Dynamic creep test declared that asphalt samples containing SEPS nanocomposite had less rutting potential compared to the control samples. As expected, further increment of temperature led to lower resistance of asphalt mixtures against rutting (for both controlled and modified mixtures), meanwhile the resistance decrease rate was less in the modified samples.