VOCs Inhibited Asphalt Mixtures for Green Pavement: Emission Reduction Behavior, Environmental Health Impact and Road Performance

Abstract

Asphalt volatile organic compounds (VOCs) produced during the construction process of asphalt pavements endanger environment and human health. Carbon black (CB), biochar (Bio), and zeolite (Zeo) were selected as VOCs inhibitors in this work, the multi-scale inhibiting effects of them on the VOCs emission behavior were explored, and environmental and health hazards of VOCs inhibited asphalt mixtures were systematically investigated. Then three inhibitors under the optimum dosage were opted to scrutinize their impact on road performance. Consequently, a total of 85 VOCs components in eight groups were detected in this research, wherein aldehydes and alkanes these two groups have the highest proportion, reaching 36% and 28%, respectively. 5%Zeo was the optimum inhibitor for the total concentration of asphalt mixture VOCs with an inhibition rate of 50.8%, followed by 1%CB, the inhibition rate of aldehydes and alkanes can reach 61.7% and 46.2%, respectively. As a whole, over 94% of the VOCs components can be suppressed. Furthermore, the addition of inhibitors to asphalt mixtures proves a boon for a benign environment and a healthy body. 5%Zeo could effectively inhibit the secondary organic aerosol formation potential, odor activity value, and non-carcinogenic hazard of VOCs with inhibition rates of 40.3%, 61.6%, and 41.2%. The efficacy of 5%Zeo is ascribed to the enormously suppressed alkanes, aldehydes, and benzene series, the largest contributors to these three indicators. Meanwhile, the inhibitor with the best inhibitory effect on ozone formation potential was 1%CB by curbing the emission of aldehydes and benzene series, with an inhibition rate of 52.9%. From the perspective of road performance, VOCs inhibited asphalt mixtures could satisfy the technical requirements. After a thorough examination, 5%Zeo is the preferred inhibitor in terms of reducing VOCs emissions, improving environmental health benefits, and affecting the road performance of asphalt mixture. This study lays the foundation for the research and design of efficient VOCs inhibitors in asphalt pavements, promoting the development of asphalt pavements with low environmental and health loads.