初始缝高比对碾压混凝土断裂性能的影响

摘要

In order to research the influence of the initial crack-depth ratio on fracture property of roller compacted concrete (RCC),a total of 18 wedge splitting RCC specimens with initial crack-depth ratio of 0.4,0.5 and 0.6 and fracture tests were carried out.The effective crack length,initial fracture toughness and unstable fracture toughness of the RCC specimens with different initial crack-depth ratio were gotten,and then the influences of the crack-depth ratio on the fracture properties of RCC were analyzed.The results show that the initial fracture toughness of RCC changes little under the different initial crack-depth ratio,can be looked as the intrinsic parameters of the material.The unstable fracture toughness of RCC increases with the initial crack-depth ratio firstly,and tends to stable gradually.The ratio of initial fracture toughness to unstable fracture toughness is maintained at 0.38.Under the same size,the smaller initial crack length,the larger pre-critical crack propagation length and the better toughness of specimens.%为了研究初始缝高比对碾压混凝土的断裂性能的影响,制作了初始缝高比为0.4、0.5、0.6共18个楔入劈拉碾压混凝土试件并进行了断裂试验,得到了不同初始缝高比试件的有效裂缝长度、起裂断裂韧度和失稳断裂韧度等断裂参数,分析了初始缝高比对碾压混凝土断裂性能的影响.结果表明:在不同初始缝高比的条件下,起裂断裂韧度的值变化较小,可认为是材料的固有参数;失稳断裂韧度随初始缝高比的增大而增大,但也逐渐趋于平缓;起裂断裂韧度与失稳断裂韧度的比值随着初始缝高比的增加维持在0.38左右;相同尺寸下,初始缝长越小,裂缝亚临界扩展量越大,试件韧性越好.