Study on asphalt volatile organic compounds emission reduction: A state-of-the-art review

A large number of harmful components are produced during asphalt pavement construction under hightemperature conditions, causing heavy environmental pollution. Adding emission reduction agents to asphalt as an effective emission reduction technology has been widely used in different nations. However, few studies have attempted to compare the used emission reduction agents and their performances, resulting in the difficulty of the selection of emission reduction agents to reduce volatile organic compounds effectively and purposely. The objective of this review paper is to systematically summarize and analyze the state-of-the-art studies on asphalt volatile organic compounds emission reduction. In this study, the components in asphalt volatile organic compounds were summarized and the restrictions on asphalt volatile organic compounds emission in different nations are reviewed and summarized firstly. Then, the commonly used emission reduction agents of asphalt volatile organic compounds were completely investigated and sorted. Afterward, the emission reduction effect and engineering performance were compared in detail. Finally, the emission reduction mechanisms of different emission reduction agents were illustrated. The main findings show that the asphalt volatile organic compounds contain nearly ten categories of main components. The emission reduction effect of inorganic porous materials is superior to others. The organic polymer materials and the appropriate amount of inorganic materials can improve asphalt's engineering performance. The emission reduction mechanisms of emission reduction agents were divided into crosslinking reaction, adsorption, and piezoelectric/thermoelectric effect according to the interaction between asphalt volatile organic compounds and emission reduction agents.