Abstract: The effect of filler-to-bitumen ratio on the low-temperature cohesive strength of SBS modified asphalt mortar was studied using quantitative testing technology. Two control variables, filler-to-bitumen ratio and temperature, were selected in the experiments. Results show that the change rule of the low-temperature cohesive strength is significantly influenced by both the filler- to-bitumen ratio and the low temperature environment. Appropriate filler-to-bitumen ratio can improve the low-temperature cohesive strength of asphalt mortar. Excessive content of mineral power fillers will produce filler agglomeration, causing additional damage points, which lead to significant decrease in the strength. The cohesive strength of the asphalt matrix increases as the environment temperature decreases. However, when the temperature is below the asphalt's embrittlement point, the asphalt matrix can be embrittled, which significantly attenuates the cohesive strength of the asphalt matrix. Therefore, the cohesive strength of the asphalt matrix, its embrittlement state and the effect of the contact interface strength of asphalt filler should be comprehensively considered in determining the optimal filler-to-bitumen ratio. Moreover, these factors should be combined with local low temperature conditions.

Key words: road engineering, low-temperature cohesive strength, filler-to-bitumen ratio, asphalt matrix strength, mineral powder filler agglomeration