Performance evaluation and field validation of a composite VOC inhibitor for asphalt pavement on the Qinghai-Tibet Plateau

This study addresses the challenge of volatile organic compound (VOC) emissions from asphalt under the compound extreme conditions of intense ultraviolet (UV) radiation and low temperatures on the Qinghai-Tibet Plateau. A composite inhibitor—C-U, comprising 6% USP (Unusual Synthetic Polymers warm-mix additive) and 5% calcium-based layered double hydroxide (CLDH)—was developed to suppress VOC release during asphalt production and service. C-U operates via a synergistic “temperature regulation–molecular encapsulation–interfacial adsorption” mechanism, achieving VOC suppression rates of 90.16% under high-temperature aging and 88.76% under UV exposure. It significantly enhances anti-aging performance, reducing the viscosity aging index (VAI) by 57% after thermo-oxidative aging and 65% after UV aging. Asphalt mixtures with C-U exhibit a 28% increase in dynamic stability, improved low-temperature flexural performance, and water stability fully compliant with JTG F40 standards. Most critically, field trials confirmed >90% reduction in total VOC emissions and a 92% decrease in ozone formation potential (OFP) during actual paving. All pavement quality indicators—including compaction degree and permeability—met specification requirements, demonstrating that C-U delivers both high environmental efficacy and engineering reliability under extreme conditions.