Preparation and properties of synergistic activated rubber powder/SBS composite modified asphalt for waterproof coatings

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The massive accumulation of waste tires poses significant environmental and safety challenges, with traditional rubber powder (RP)-modified asphalt systems often suffering from poor compatibility, thermal instability, and inadequate durability for waterproofing applications. To address these limitations, this study introduces a synergistic activation strategy combining aromatic oil swelling and thermal devulcanization to prepare Synergistic Activated Rubber Powder (SARP), which is further compounded with styrene-butadiene-styrene (SBS) to develop high-performance waterproof coatings. The experimental results showed that the addition of SARP significantly improved the compatibility and thermal stability of asphalt, reduced the high-temperature viscosity, and enhanced the low-temperature performance. Orthogonal experiments (L₁₆ array) were designed to optimize four key factors (SARP content, SBS content, preparation temperature, and shear time), and the optimal formulation were15% SARP, 2% SBS, 175°C, 50 min. On this basis, SARP/SBS composite modified asphalt coatings were prepared and tested for their mechanical properties, stress relaxation, self-healing properties and resistance to water dispersion. The results showed that the SARP/SBS modified asphalt coatings exhibited excellent properties in terms of elongation, self-healing, fatigue resistance and resistance to water dispersion pressure, as well as good stability in simulated substrate behavior tests. The results demonstrate the good performance of SARP/SBS composite modified asphalt in the application of waterproofing coatings.