Development and Performance Evaluation of Ultra-Low Temperature Crack-Resistant Modified Hydraulic Asphalt Based on Response Surface Methodology

Numerous factors affect modified asphalt's performance, and it would take a long time to develop modified asphalt that satisfies the needs of ultra-low temperature conditions using traditional procedures. Response Surface Methodology (RSM) allows for the quick development of crack-resistant modified asphalt under multiple variables. This study uses the brittle point as the indicator response value for crack resistance. The Box-Behnken model is utilized for the experimental design involving modifiers, stabilizers, and compatibilizers. A predictive model for the brittle point has been created through regression analysis, achieving a correlation coefficient (R^2) of 0.9897. Based on this model, modified asphalt samples were produced by adjusting the modifier dosage. The low-temperature crack resistance and tensile properties were assessed through brittle point tests and tensile elongation tests. The findings indicate that increasing the modifier dosage significantly lowers the asphalt's brittle point and enhances its cohesive energy, thereby improving the crack resistance and durability of asphalt concrete in low-temperature conditions. To further validate these results, the impact of modified asphalt on concrete performance was examined in terms of water stability, permeability, slope flow, and freeze-thaw tests. The results showed that the freeze-fracture temperature of the concrete reached -46.7°C, while the asphalt's brittle point was -37.6°C. The high-temperature slope flow value was 0.473, which is below the standard requirement. Other performance indicators were also highly satisfactory. Thus, designing asphalt formulations using Response Surface Methodology is a viable approach.