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强度标准影响水泥稳定碎石组成尤其是水泥剂量,而水泥剂量直接影响水泥稳定碎石强度与抗裂性能,强度不足导致基层疲劳断裂,抗裂性能不足导致基层产生温缩或干缩裂缝。水泥稳定碎石压实方式不同,其压实效果与力学强度也不同。目前实验室内重型击实与静压成型方式(QSCM)制备试件研究和评价水泥稳定碎石路用性能,而现场实际则普遍采用振动碾压方式压实水泥稳定碎石基层。为此,在验证实验室内试件垂直振动压实方法 (VVCM)可靠性基础上,采用VVCM水泥稳定碎石力学参数分析了施工期和运营期水泥稳定碎石的荷载响应和疲劳累积损伤,提出了控制疲劳断裂的水泥稳定碎石强度标准。结果表明:VVCM试件与现场芯样的无侧限抗压强度基本吻合;VVCM试件7天无侧限抗压强度是QSCM试件的2.3倍;建议水泥稳定碎石7天无侧限抗压强度≮7.0MPa;水泥稳定碎石静压法及其相应强度标准不适宜于材料设计。
The strength standard affects the composition of cement stabilized macadam, especially the cement dosage, while the cement dosage directly affects the strength and crack resistance of cement stabilized macadam. The insufficient strength leads to the fatigue fracture of the primary layer and the lack of crack resistance, resulting in the occurrence of temperature shrinkage or shrinkage cracks in the primary layer. Cement stabilized macadam compaction method is different, the compaction effect and mechanical strength are also different. In present laboratory, heavy compaction and hydrostatic compaction (QSCM) test specimens are used to study and evaluate the road performance of cement stabilized macadam, while in practice, vibration compaction is commonly used to compaction the cement stabilized macadam base. Therefore, on the basis of verifying the reliability of vertical vibration compaction method (VVCM) in laboratory specimens, the load response and fatigue cumulative damage of cement stabilized gravel during construction and operation period were analyzed by using the mechanical parameters of VVCM cement stabilized macadam. The cement stabilized gravel strength standard for controlling fatigue fracture was proposed. The results show that the unconfined compressive strength of VVCM specimen is basically consistent with that of on-site core specimen. The unconfined compressive strength of VVCM specimen is 2.3 times of that of QSCM specimen in seven days. It is suggested that cement stabilized macadam should be unconfined for 7 days Compressive strength ≮ 7.0MPa; cement stabilized gravel static pressure method and its corresponding strength standards are not suitable for material design.