水泥稳定碎石混合料疲劳性能

根据水泥稳定碎石基层在车辆荷载作用时的受力状态, 采用不同水泥剂量和级配的混合料分别在室内进行强度和劈裂疲劳试验。无侧限抗压强度试验结果表明: 中值级配、水泥剂量仅为2.5%的混合料的7 d无侧限抗压强度已满足规范的要求, 故可以适当降低水泥稳定碎石基层的水泥用量标准。劈裂疲劳试验结果表明: 具有较高水泥剂量的水泥稳定碎石混合料的力学敏感性较低, 也就是说, 在相同的结构条件下, 其抗超载、超限的能力较好。基于劈裂疲劳试验结果, 采用回归方法得到具有较高判定系数的水泥稳定碎石混合料疲劳方程, 最小判定系数为0.848 3, 回归参数值均处于波动范围7~28之内。

Fatigue performance of cement-stabilized macadam mixture

According to the stress state of cement-stabilized macadam base under vehicle load, the strength and splitting fatigue tests on the macadam materials with various cement dosages and gradations in doors were carried out.The test result of unconfined compressive strength shows that the 7th day's unconfined compressive strengths of the mixtures with middle-rang gradations and 2.5% cement dosage meet with the requirement of relative criterion, therefore, the cement dosage criterion can be debased properly for cement-stabilized macadam base.The result of splitting fatigue test indicates that the cement-stabilized macadam mixture with higher cement dosage has lower load sensitivity.In other words, under the same construction condition, its capability to endure overload or over-axial-load limit force is better.Based on the result of splitting fatigue test, the fatigue formulae with high correlation coefficients are educed by using regression method, the minimal determinant coefficient is 0.848 3, and the regression parameters values are in 7~88.