不同养护条件对半柔性路面材料性能的影响

Influence of Different Maintenance Conditions on Performance of Semi-flexible Pavement Materials

为探究养护条件对半柔性路面材料抗裂性能的影响规律,首先,基于抗压和抗折试验,表征了2种不同强度灌浆料在3种不同养护条件下的强度特性。其次,基于弯拉荷载模式的半圆弯拉试验(SCB)和间接拉伸试验(IDT),研究了灌注后的2种半柔性路面材料在3种不同养护条件下的宏观抗裂力学性能。最后,采用扫描电镜(SEM)分析了不同养护条件和不同养护龄期水泥基灌浆料的微观结构,揭示了养护温度与养护湿度对水泥基灌浆材料的水化产物和分布的影响,并结合宏观力学性能探明了养护条件对抗裂性的作用机理。结果表明:养护条件对浆料强度、断裂特性和微观结构均有明显影响,浆料3 d抗压强度与SCB测试的峰值荷载具有较好的线性相关性;在25℃时,室温养护条件SFP试件的抗裂性能最佳。在-10℃时,普通型浆料的SFP试件在高温养护时性能最佳,早强型浆料的SFP试件则在室温养护条件时性能最佳;浆料微观结构致密程度与其抗压抗折强度有较好的对应性,浆料微观结构致密时SFP试件在25℃具有较好的抗裂性能,而浆料具有微孔结构,与沥青形成良好的界面连接,其SFP试件在-10℃时具有较好的抗裂性能。研究结果对半柔性路面材料的铺筑与应用具有指导意义。

In order to explore the rule of influence of curing condition on the crack resistance of semi-flexible pavement materials,first,the strength characteristics of 2 kinds of grouting materials with different strengths under 3 curing conditions are characterized based on compressive and flexural tests.Second,based on semicircular bending(SCB)test and indirect tensile(IDT)test under flexural and tensile load modes,the macroscopic anti-cracking mechanical properties of 2 semi-flexible pavement materials under 3 curing conditions after grouting are investigated.Finally,the microstructures of cement-based grouting material with different curing ages under different curing conditions are analyzed by using scanning electron microscopy(SEM),the influences of curing temperature and curing humidity on the hydration products and distribution of cement-based grouting materials are revealed,and the mechanism of curing conditions on the crack resistance is explored combining with macroscopic mechanical properties.The result shows that(1)The curing conditions significantly affect the strength,fracture characteristics and microstructure of grouting material,and the 3 d compressive strength of the grouting material has an excellent linear correlation with the peak load of the SCB test.(2)At 25℃,the SFP specimens under room temperature curing condition own well crack resistance.(3)At-10℃,the SFP specimens with general grouting material perform well under high-temperature curing condition,while the SFP specimens with early-strength grouting material perform well under room temperature curing condition.(4)The density of the microstructure of grouting material corresponds well to its compressive and flexural strengths,the SFP specimens own well crack resistance at 25℃with the compact microstructure of grouting material.The grouting material has microporous structure,forming a good interface connection with asphalt for excellent crack resistance at-10℃.The research result has guiding significance for paving and applying semi-flexible pavement materials.