水泥填料对心墙沥青混凝土长期水稳定性的影响

Influence of cement filler on long-term water stability of core wall asphalt concrete

以优选的心墙沥青混凝土配合比为基础,分别采用质量分数为12%的石灰石粉、6%水泥+6%石灰石粉、12%水泥作为填料配制沥青混凝土试件,研究水泥填料对采用天然砾石骨料的心墙沥青混凝土长期水稳定性的影响。试验结果表明:采用12%石灰石粉为填料的沥青混凝土水稳定系数随浸水时间的延长而不断减小,且在浸水75 h后水稳定系数降至0.88,已不满足心墙沥青混凝土水稳定系数大于或等于0.90的要求;采用12%水泥、6%水泥+6%石灰石粉为填料的沥青混凝土水稳定系数随浸水时间的延长先增大后减小,且在浸水375 h后达到最大,分别为1.02和0.98,在浸水1 500 h后水稳定系数仍然能够满足规范要求;用水泥替代部分石灰石粉作填料也可有效改善心墙沥青混凝土的长期水稳定性。

Based on the optimized mixture ratio of core wall asphalt concrete,asphalt concrete specimens were prepared using 12% limestone powder,6% cement and 6% limestone powder,and 12% cement,respectively. The effect of cement fillers on long-term water stability of core wall asphalt concrete with the natural gravel aggregate was studied. The results show that the water stability coefficient of the specimen with 12% limestone powder decreases with the increase of the immersion time,and the water stability coefficient decreases to 0. 88 when the immersion time is 75 h,indicating that it does not meet the requirement that the water stability coefficient of core wall asphalt concrete be greater than or equal to0. 90. The water stability coefficients of the specimens with 12% cement or 6% cement and 6% limestone powder first increase and then decrease with the increase of the immersion time,and reach their maximum values of 1. 02 and 0. 98,respectively,when the immersion time is 375 h. The water stability factor can still meet the specification requirements when the immersion time is 1 500 h. It can effectively improve the long-term water stability of core wall asphalt concrete to use cement to replace limestone powder.