Characterization of fume composition and rheological properties of asphalt with crumb rubber activated by microwave and TOR

- CR activated by microwave and TOR reduces PAHs and sulfur compounds in asphalt fumes.
- Microwave treatment on CR enhances relaxation performance of modified asphalt.
- TOR greatly improves viscoelastic behavior of CR modified asphalt at high temperatures.

This paper studied asphalt fume chemical composition, rheological properties and microstructure of asphalt with crumb rubber (CR) activated by microwave and trans-polyoctenamer (TOR). To that end, asphalt fume was trapped through laboratory fume generation and capture system, which was subsequently analyzed by Gas Chromatography-Mass Spectrometry system (GC-MS). Moreover, the rheological behavior and microstructure of CR modified asphalt (CRMA) were characterized by dynamic shear rheometer (DSR) and FTIR. The GC-MS results indicated that CR activated by microwave and TOR reduces the contents of PAHs and sulfur compounds, implying the lower toxicological potential of fume. TOR has the greater effect of reduction in the toxicological species. The rheological results indicated that CR activated by TOR significantly improves modulus, zero shear viscosity (ZSV), and recovery ability of CRMA at high temperatures, which cause asphalt binder having the stronger resistance to rutting. The enhancement in thermo-mechanics is due to chemical cross-linking among TOR, rubber, and asphalt, which was verified by FTIR results. On the other hand, microwave treatment on CR affects high temperature performance of CRMA negatively in comparison to the untreated CRMA. However, microwave treatment leads to the faster stress relaxation response of CRMA, indicating the stronger resistance to thermal cracking.

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