SMA混合料冻融循环性能试验及超声波法评价

Test on Characteristics of SMA Mixtures Under Freeze-thaw Cycle and Ultrasonic Evaluation Method

为研究SMA混合料的冻融循环性能,通过对SMA-13进行多次冻融循环试验,分析SMA混合料在经历不同冻融循环次数后其水稳定性、高温稳定性、渗水性能的变化规律,提出将水泥和消石灰作为外加剂替代部分矿粉来改善SMA混合料冻融循环性能的方法,并采用超声波法测试其冻融循环性能的变化规律。结果表明:掺加20%消石灰(质量分数)可显著提高SMA混合料的冻融循环性能;超声波法测试SMA混合料冻融循环性能时,受孔隙率影响较大;提出的修正方法可显著提高超声波法评价SMA混合料冻融循环性能的准确性。

To analyze SMA mixture characteristics under freeze-thaw cycle,the change laws of water stability,high temperature stability and permeability of SMA-13 mixtures were analyzed after several freeze-thaw cycles. A solution was proposed to improve the SMA mixture characteristics of freeze-thaw cycles by replacing mineral powder with cement and lime in the mixtures,and change laws of SMA mixture characteristics of freeze-thaw cycle were measured by using ultrasonic method.The results show that adding 20% of hydrated lime（mass fraction）has a significant effect on the improvement of SMA mixture characteristics of freeze-thaw cycles.When ultrasonic method is used to test SMA mixture characteristics of freeze-thaw cycle,it is largely affected by the air void ratio of SMA.The proposed revised method can significantly improve the accuracy of ultrasonic evaluation method.