Reducing automotive exhaust: road performance, purification efficiency, and purification mechanism of self-purified asphalt concrete

To reduce automobile exhaust, self-purified asphalt concrete was prepared with a tourmaline/biochar/diatomite (TBD) purifying agent. The road performance of self-purified asphalt concrete was clarified. The purification effect of self-purified asphalt concrete on automobile exhaust was explored, and the purification efficiency mechanism was revealed. The results indicated that the high-temperature performance and water stability improved, while the low-temperature performance of self-purified asphalt concrete first improved and then decreased with the increase of TBD content. The road performance of self-purified asphalt concrete was the best with a TBD content of 20%. The purification rate of self-purified asphalt concrete on automobile exhaust increased with increasing temperature. The maximum purification rates for CO, CO2, NOx, and HC were 34.31%, 37.87%, 61.79%, and 44.79%, respectively. The purification efficiency of self-purified asphalt concrete on automobile exhaust decreased with the increase in height. At different heights, self-purified asphalt concrete has the best purification efficiency on NOx, with a purification rate distribution of 42.3%-55.85%. TBD adsorbed automobile exhaust through a porous structure and degraded it by the spontaneous polarization effect.