水泥稳定碎石基层材料微裂技术研究

Research on Micro-cracking of Cement Stabilized Macadam Base

微裂技术是减轻或避免水泥稳定基层反射裂缝的新思路。为实现微裂技术在实际工程中的合理运用,分别利用室内振动击实仪和现场振动碾压两种方法对微裂程度的控制进行研究,并通过在不同时间点测定微裂后水泥稳定碎石力学强度,分析研究微裂缝愈合特性及其随时间的变化规律;将微裂技术应用到实际工程中并进行现场试验,在验证理论成果的基础上,研究水泥稳定碎石基层微裂技术施工过程、测试方法以及应用效果。结果显示:在不影响材料后期强度恢复的基础上,同时考虑能够最大程度释放材料收缩应力,微裂技术宜在水泥稳定碎石基层施工完成后养生2d后进行,微裂程度以抗压回弹模量下降40%为最佳。

Micro-cracking is a new idea to reduce or avoid the reflective cracking of cement stabilized macadam base. In order to realize the rational use of micro-cracking in the project practice, vibrating compactor in the laboratory and vibratory roller in the field are used to research on the control of micro- cracking degree, and then the mechanical strength of cement stabilized macadam is measured after micro- cracking at different times so as to study on the micro-cracks healing characteristics and the variation with time; then the micro-cracking is applied to the engineering, and the field experiment is carried out to validate theoretical results, finally the construction process, test methods and application results of micro- cracking applied on cement stabilized macadam base are discussed. The result shows： on the basis of not affecting the strength recovery and considering the release of shrinkage stress, the suitable time to carry out micro-cracking is in the second day after the cement stabilized macadam base construction, the best micro-cracking degree is around 40% （the decrease percentage of compression rebound modulus）.