Effect of styrene-butadiene-styrene (SBS) on the rheological behavior of asphalt binders

The binders in pavement could support the loading in either linear or nonlinear regime. The linear viscoelasticity of asphalt binders was well established, however, a few of researches focused on the nonlinear viscoelasticity of asphalt binders. Here, this paper deals with the effects that SBS exerts on the linear and nonlinear rheological behavior of asphalt binders. The nonlinear rheological behavior of one kind of neat asphalt binder and the corresponding SBS modified asphalt binders under large amplitude oscillatory shear stress (LAOS stress) is analyzed by Fourier Transform (FT)-rheology and strain decomposition methods. The linear viscoelastic measurements show that the elastic proportion and the complexity of rheological behavior of the asphalt binder increases with increase in SBS content. The nonlinear viscoelastic measurements reveal that the relative nonlinearity of asphalt binders increases with increase in stress and decrease in frequency; the relationship between I-3/I-1 and stress amplitude can obey the sigmoidal function; the intrinsic nonlinearity Q(0) decreases with increase in frequency and increases with the increase of SBS content. Both the FT analysis and decomposition results show that the nonlinearity of SBS modified asphalt binder is more obvious than neat asphalt binder and increases with the increase of SBS content. SBS could increase the nonlinearity and the elastic proportion of asphalt binder and decrease its fluidity. All the studied binders exhibit stress softening and stress thinning under all the studied test conditions. (C) 2019 Elsevier Ltd. All rights reserved.