The Road Performance, VOCs Emission Behavior, and Emission Mechanism of Rubber Powder/SBS-Modified Asphalt

To reduce volatile organic compounds (VOCs) emissions from rubber powder/SBS modified asphalt under high temperatures, the key road performance characteristics of asphalt modified with different proportions of rubber powder/SBS were investigated. The optimal rubber powder proportion was determined. The VOCs emission behavior of rubber powder/SBS modified asphalt before and after desulfurization was compared and analyzed using headspace gas chromatography-mass spectrometry (GC-MS). The VOCs emission mechanisms were revealed through microstructural testing. The results showed that the rubber powder/SBS modified asphalt exhibited good road performance with the optimal rubber powder content of 15%. As more rubber powder was added, the total VOCs emissions increased. Desulfurized rubber powder/SBS modified asphalt demonstrated superior performance in controlling harmful VOCs emissions. Undesulfurized rubber powder/SBS modified asphalt released more complex and toxic components compared to desulfurized rubber powder/SBS modified asphalt. The content of xylene was significantly higher than desulfurized rubber powder. Infrared spectroscopy analysis further validated the GC-MS results. Consistency in functional group changes was shown by both methods. Scanning electron microscopy revealed that the original cross-linked network of the adhesive powder was disrupted by desulfurization treatment. Interfacial activity and dispersion of the particles were enhanced. This led to the establishment of a more stable structural system and a reduction in VOCs emissions. Therefore, road performance was ensured, and VOCs emissions were significantly reduced by desulfurized rubber powder/SBS modified asphalt. This expands the utilization rate of waste rubber powder and reduces its environmental pollution.