A novel low-emission road asphalt: Preparation, road performance, and emission reduction efficacy

To efficiently reduce the release of hazardous substances from road asphalt (AHS) under high temperatures, a novel low-emission asphalt was prepared with tourmaline/biochar/diatomite (TBD) composite and base asphalt in this research. The testing and evaluation method for the emission reduction efficacy of AHS was proposed. The preparation process parameters of TBD modified asphalt (TBD-A) were optimized. The micromorphology and the road performance of TBD-A were deeply studied. The AHS emission characteristics and emission reduction effects of TBD-A were clarified. The optimal ratio of TBD was recommended. The results indicated that the optimal shear temperature, shear speed, and shear time for preparing TBD-A were recommended as 150 degrees C, 3000 rpm/min, and 40 min, respectively. TBD was equally dispersed throughout asphalt and worked well with it according to scanning electron microscopy. TBD improved the temperature sensitivity, enhanced the high temperature and aging resistance, improved the deformation resistance, and promoted the low temperature cracking resistance of asphalt. TBD-A emitted fewer AHS than basic asphalt. Increasing temperature and TBD content enhanced the emission reduction effect of TBD-A. The highest emission reduction rate of AHS exceeds 70 %. Considering the road performance and emission reduction efficiency of TBD-A, the TBD content was recommended as 20 %.