Improving flame retardancy, fume suppression and mechanical properties of SBS modified binder using nano-porous fibers prepared by electrospinning

The current study utilizes polyacrylonitrile (PAN) as the foundational material, augmented with multi-walled carbon nanotubes (MWCNTs) and nano-calcium carbonate (nCC) as additives. Utilizing electrospinning techniques, micro-nanoscale composite fibers possessing elevated surface areas (MCE-PAN) were synthesized. Experimental data indicate that MCE-PAN enhances both the flame-retardant and mechanical attributes of the modified asphalt binder. Specifically, MCE-PAN elevates the limiting oxygen index (LOI) of the modified asphalt binder by 25.24%, increases smoke suppression efficiency by 10.67%, elevates the decomposition temperature by 105℃, and substantially curtails smoke emission. MCE-PAN manifests significant hydrophobic characteristics, thus augmenting the interfacial interactions between PAN fibers and the asphalt binder. Additionally, at an ambient temperature of 46℃, the complex modulus (G*) of the MCE-PAN/SBS/MA modified asphalt binder, with a 0.1% loading, surged by 52% relative to the SBS modified asphalt binder (SBS/MA); the storage modulus (G') escalated by 101.4%, and the loss modulus (G'') increased by 75.6%. Under low-temperature conditions, the MCE-PAN/SBS/MA modified asphalt binder demonstrates enhanced resistance to crack propagation. This investigation not only introduces an innovative approach to fiber synthesis but also elucidates its applicability in augmenting the performance and flame retardancy of asphalt pavements. It thereby holds significant practical, environmental, and energy-saving implications for sustainable, flame-retardant asphalt pavement, particularly in tunnel applications and high-temperature settings.