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为分析冻融循环对苯乙烯-丁二烯-苯乙烯(SBS)和橡胶粉(CR)改性沥青混合料抗裂性能的影响,首先,分别对盐溶液冻融循环和水溶液冻融循环改性沥青混合料进行了半圆试件弯拉试验,同时采用数字散斑相关法(DSCT)对加载过程试件表面的散斑图像进行处理,提取试件表面随着载荷变化的位移场和应变场信息;然后,通过分析变形场信息确定沥青混合料的抗裂性能,并与断裂韧性试验结果进行对比。结果表明:水平应变较适合用于对沥青混合料的抗裂性能开展特性研究;由水平应变-时间曲线可知,冻融循环后SBS和CR改性沥青混合料的抗裂性能均有所劣化,且盐溶液冻融循环对沥青混合料抗裂性能的影响要大于水溶液冻融循环的;与SBS改性沥青混合料相比,CR改性沥青混合料的抗裂性能较好。所得结论表明DSCT的分析结果与断裂韧性试验的分析结果一致,采用DSCT评价沥青混合料的抗裂性能是可行的。
In order to analyze the effect of freeze-thaw cycles on the crack resistance of styrene-butadiene-styrene (SBS) and rubber powder (CR) modified asphalt mixture, firstly, the salt solution freeze-thaw cycle and the aqueous solution freeze- Asphalt mixture was subjected to the bending test of the semicircular specimen, and the digital speckle correlation method (DSCT) was used to deal with the speckle images on the specimen surface during the loading process. The displacement and strain fields Then, the anti-cracking performance of asphalt mixture was determined by analyzing the deformation field information and compared with the results of fracture toughness test. The results show that the horizontal strain is suitable for the study of the crack resistance of asphalt mixture. The horizontal strain-time curve shows that the cracking resistance of SBS and CR modified asphalt mixture are both deteriorated, The effect of salt solution freeze-thaw cycle on the anti-cracking performance of asphalt mixture is greater than that of freeze-thaw cycle. Compared with SBS modified asphalt mixture, CR modified asphalt mixture has better crack resistance. The results show that the analysis results of DSCT are consistent with the analysis results of fracture toughness test. It is feasible to evaluate the crack resistance of asphalt mixture by DSCT.