水泥稳定碎石早期损伤自愈合疲劳特性试验研究

Experimental Study on Fatigue Performance of Early Damage Cement Stabilized Macadam in the Process of Self-healing

为了使水泥稳定碎石基层微裂技术在实际工程应用中的理论依据得到进一步完善,对水泥稳定碎石早期损伤自愈合疲劳性能进行全面和深入的研究。使用振动压实仪成型水泥稳定碎石梁式试件,并在不同微裂时间对梁式试件进行不同程度的微裂;在龄期为90 d时,通过弯拉强度试验和疲劳试验测定微裂前后水泥稳定碎石材料的弯拉强度和疲劳寿命次数,并对试验结果进行分析。研究微裂后水泥稳定碎石材料早期损伤自愈合疲劳寿命的变化规律,并且应用Weibull分布建立了水泥稳定碎石微裂疲劳方程。研究结果表明:微裂前后的水泥稳定碎石材料疲劳寿命随应力水平增加均呈现出线性递减的规律;微裂程度为20%和30%时,水泥稳定碎石材料的疲劳寿命与未微裂时水平基本一致,微裂程度为40%的水泥稳定碎石材料的疲劳寿命相对降低,但仍在使用要求范围内;微裂时间对疲劳试验结果无显著性影响。

For further consummating the theoretical basis of the microcracking technology of cement stabilized macadam base in the practical engineering application,a comprehensive and in-depth research on the fatigue performance of cement stabilized macadam after early damage and late self-healing has been conducted. Using vibration compaction meter,beam specimens of cement stabilized macadam were made and cracked with different degrees and time of microcracking. At the age of 90 d,the flexural strength and fatigue life of the cement stabilized macadam before and after microcracking were measured in the flexural strength test and the fatigue test,and the test results were analyzed. The changing rules of the fatigue life of the cement stabilized macadam ＇s early damage and self-healing after microcracking were researched and the microcracking fatigue equation of cement stabilized macadam was established by the Weibull distribution. The results show： the fatigue life of cement stabilized macadam presents a linear law of decrease with the increase of stress level both before and after microcracking; at the microcracking degree of 20% and 30%,the fatigue life of cement stabilized macadam is basically the same with that without microcracking and at the degree of 40% the fatigue life of cement stabilized macadam is relatively lower but still within the scope of the use requirement; the microcracking time has no significant influenceon the results of fatigue test.