盐冻融循环下温/热拌胶粉改性沥青混合料高低温性能研究

对温拌胶粉改性沥青混合料(CR-WMA)、热拌胶粉改性沥青混合料(CR-HMA)进行了三轴重复蠕变试验、小梁弯曲试验及弯曲蠕变试验,研究了其在盐冻融循环作用前后的高低温性能,并利用Burgers模型对蠕变数据进行了拟合分析。结果表明:随着冻融循环次数的增加,CR-WMA与CR-HMA的高低温性能均逐渐下降,在冻融循环次数为0~15次时高低温性能降低速度最快,之后变化趋于平缓,而CR-WMA比CR-HMA性能降低的速度要缓慢、程度要小;随着盐浓度的增加,CR-WMA与CR-HMA的高低温性能均逐渐下降,在盐浓度为8%(质量分数)时下降幅度达到最大,而CR-WMA比CR-HMA下降趋势要缓和。通过蠕变数据拟合出的粘弹参数变化规律也验证了上述结论,均表明掺加SDYK型表面活性剂温拌剂可有效地提高胶粉改性沥青混合料的高低温性能,使其抵抗盐侵蚀及冻裂病害的能力更佳。

High and Low Temperature Performance of Warm/Hot-Mixed Crumb Rubber Modified Asphalt Mixture under Salt Freezing-Thawing Cycles

Through the triaxial repeated creep test, trabecular bending test, and bending creep test, the high and low temperature performance of the warm-mixed crumb rubber modified asphalt mixture (CR-WMA) and the hot-mixed crumb rubber modified asphalt mixture (CR-HMA) under the action of salt freezing-thawing cycles were studied, and the Burgers model was used to fit and analyze the creep data. The results show that with the increase of number of times of freezing-thawing cycles, the high and low temperature performance of CR-WMA and CR-HMA gradually decreases. When the number of times of freezing-thawing cycles is 0 to 15, the high and low temperature performance reduces the speed fastest, and later the change tends to be gentle. The performance of CR-WMA reduces more slowly and less than that of CR-HMA. With the increase of salt concentration, the high and low temperature performance of CR-WMA and CR-HMA gradually decreases. When the salt concentration is 8%, the decrease amplitude reaches the maximum. The downward trend of CR-WMA is more moderate than that of CR-HMA.The change law of viscoelastic parameters fitted by creep data also verified the above conclusions, indicating that CR-WMA doped with SDYK surfactants has more stable high and low temperature performance than CR-HMA, and has better resistance to salt erosion and crack resistance.