Rheological and nano-mechanical characteristics of bituminous mastics containing waste and ordinary filler at different temperatures

This study has focused on the effect of cement kiln dust (CKD) as a waste filler on the rheological and nano mechanical properties of bituminous mastic in comparison with limestone powder (LSP) as an ordinary filler. Mastics were prepared using three filler to bitumen (F/B) ratios including, 0.4, 0.8 and 1.2. The strategic highway research program (SHRP) standard and multiple stress creep recovery (MSCR) test methods were used to evaluate the behavior at high performance temperatures. Also, SHRP standard and time sweep methods were performed to evaluate the fatigue behavior at medium performance temperatures. Low temperature properties were examined by bending beam rheometer. Field emission scanning electron microscopy (FESEM) was used to evaluate the quality of filler distribution in the mastic. Furthermore, the nano-mechanical properties of mastics were examined by atomic force microscopy (AFM) including topography roughness, elastic modulus and adhesion force. Fundamental evaluations with AFM indicated that, at a constant F/B ratio, CKD filler with a higher fineness and specific surface area showed higher elastic modulus and lower adhesion than LSP. Also, the FESEM analysis for filler distribution showed the highest homogeneity coefficient at F/B ratio of 0.8. A significant relationship was observed between SHRP rutting parameter and creep variables in MSCR method. Both methods indicated a superior rutting resistance for CKD than LSP. Although, there was no clear relationship between SHRP fatigue parameter and the time sweep outcomes.

Automated summary

This study investigated the effect of cement kiln dust (CKD) as a waste filler on the properties of bituminous mastic compared to limestone powder (LSP) as a normal filler. The results showed that CKD filler exhibited higher elastic modulus and lower adhesion compared to LSP. The analysis of filler distribution indicated the highest homogeneity coefficient at an F/B ratio of 0.8. The SHRP and MSCR methods demonstrated that CKD had better rutting resistance than LSP.