Creep and fatigue properties of asphalt mastic with steel slag powder filler

Steel slag powder (SSP) was selected as an inorganic micro powder filler instead of limestone powder (LSP) to prepare asphalt mastic in this paper. Firstly, the microscopic characteristics of SSP and LSP such as particle size distribution, surface morphology, phase composition and chemical composition were characterized by laser particle size analyzer, scanning electron microscopy (SEM), X-ray diffraction (XRD) analyzer, and X-ray fluorescence (XRF) analyzer. Then, the composition and content of chemical functional groups of asphalt mastics were studied by fourier transform infrared spectrometer (FTIR). Finally, the effect of SSP on the creep and fatigue properties of asphalt mastics was investigated via multiple stress creep recovery (MSCR) and time scanning experiments using a dynamic shear rheometer (DSR).The results showed that the addition of SSP as mineral filler instead of LSP to asphalt binder enhanced the deformation resistance and the fatigue life of the asphalt mastics.The complex shear modulus of asphalt mastics show an increase trend with an increase in the SSP content. Compared with LSP asphalt mastic, the complex shear modulus of SSP asphalt mastic ( SSP content 30%, 50%, 100%) increased by 84.9%, 118.0% and 256.1%, respectively. From the perspective of structural design and material selection, the fatigue life NDER corresponding to the cumulative dissipative energy rate(DER) is recommended to analyze the fatigue life of asphalt mastics.The results of the MSCR and time scanning experiments demonstrated that the use of a combination of SSP and LSP as filler could be an effective approach for comprehensive utilization of steel slag in asphalt mixture.