玻璃纤维水泥稳定碎石收缩及柔化抗裂性能研究

Research on Shrinkage and Softening Crack Resistance of Glass Fiber Cement Stabilized Crushed Stone macadam

为减少沥青路面反射裂缝的产生及扩展,提高沥青路面的整体抗裂性和延长其使用寿命,采用经济效益良好、取材便捷、增韧效果佳的玻璃纤维来改善水泥稳定碎石的收缩及抗裂性能,并通过干燥收缩试验、温度收缩试验、弯曲韧性试验、断裂能试验分析了玻璃纤维对水泥稳定碎石柔化抗裂能力的改善效果。研究结果表明:在玻璃纤维体积掺量为0.05%、0.10%、0.15%时水泥稳定碎石30 d龄期干燥收缩系数分别较普通水泥稳定碎石降低了6%、13%、16%;其平均温缩系数分别降低了6%、16%、19%,玻璃纤维的掺量从0.05%提高到0.10%时平均温缩系数的降低幅度最大,达到了10%,此时的提升效果最佳;3种不同玻璃纤维掺量的水泥稳定碎石的弯拉韧度分别增加了25.9%、48.1%、150.0%,相对于普通水泥稳定碎石,加入0.10%玻璃纤维改性后极限破坏荷载提高了超过20%,破坏时的挠度增大了53%;水泥稳定碎石断裂能增益比达到了1.225。玻璃纤维的加入可以有效抑制水泥稳定碎石材料的干燥收缩和温度收缩变形,同时改性后水泥稳定碎石韧度和破坏时消耗的能量远远大于普通水泥稳定碎石,增强了水泥稳定碎石的收缩和抗裂性能。

In order to reduce the generation and expansion of reflective cracks in asphalt pavements,to improve the overall crack resistance of asphalt pavements and prolong their service life,glass fibres,which were economically efficient,convenient to obtain and have good toughening effect,were used to improve the shrinkage and crack resistance of cement stabilised aggregates macadam,and the effect of glass fibres on the softening and crack resistance of cement stabilised aggregates macadam was analysed through drying shrinkage tests,temperature shrinkage tests,bending toughness tests and fracture energy tests.The results of the study showed that three different types of glass fibres were used to improve the shrinkage and cracking resistance of cement stabilised aggregates macadam.The results showed that the drying shrinkage coefficients of cement stabilized aggregates macadam with three different glass fibre doping levels decreased by 6%,13%and 16%respectively at 30 d compared with those of ordinary cement stabilized aggregates macadam;the average temperature shrinkage coefficients decreased by 6%,16%and 19%,respectively;the average temperature shrinkage coefficient decreased the most when the glass fibre doping level was increased from 0.05%to 0.10%,reaching 10%,and the best improvement effect was achieved at this time.The bending and tensile toughness of the three different glass fibre admixtures increased by 25.9%,48.1%and 150.0%,respectively;the ultimate breaking load increased by more than 20%and the deflection at breakage increased by 53%after the addition of 0.10%glass fibre modification compared to ordinary cement stabilised aggregates macadam;the fracture energy gain ratio of cement stabilised aggregates reached 1.225.The addition of glass fibre could effectively inhibit the drying shrinkage and temperature shrinkage deformation of cement stabilised aggregates macadam,while the modified cement stabilised aggregates macadam were much tougher and consumed much more energy at breakage than ordinary cement stabilised aggregates macadam,which was important for enhancing the shrinkage and crack resistance of cement stabilised aggregates macadam.