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似水泥材料断裂能的尺寸效应可通过局部断裂能沿试件韧带方向的分布得以合理解释。该文针对砂浆三点弯曲切口梁,通过解析方法建立了梁的极限荷载与裂缝尖端区域局部断裂能的关系,并进行了不同高度、不同缝高比的三点弯曲梁试验。通过极限荷载的理论与试验结果的对比,确定了不同初始裂缝尖端区域局部断裂能的大小,进而得到了局部断裂能沿试件韧带方向的分布。结果表明,与混凝土中局部断裂能的分布规律相似,砂浆局部断裂能分布受试件的前后边界及裂缝尖端位置的虚拟边界影响,呈三线性,即远离试件后边界和虚拟边界时,局部断裂能值几乎保持不变;靠近两个边界时,局部断裂能值不断降低。因此,局部断裂能分布的三线性模型不仅适用于混凝土,对砂浆等似水泥材料同样适用。
The size effect of fracture energy of cement-like material can be reasonably explained by the distribution of local fracture along the ligament of the specimen. In this paper, the relationship between the ultimate load of beam and the local fracture energy in the crack tip region is established by analytical method for three-point curved notched beams of mortar. Three-point bending beams with different heights and different seam-height ratios are tested. By comparing the theoretical and experimental results of ultimate load, the local rupture energy of different initial crack tip regions was determined, and the distribution of local rupture along the ligament of the specimen was obtained. The results show that the distribution of local fracture energy in concrete is similar to that in concrete. The distribution of local fracture energy in mortar is influenced by the virtual boundary of the front and back boundary and the crack tip position of the specimen, which is trilinear. That is to say, far away from the posterior boundary and the virtual boundary, The fracture energy value remains almost unchanged; when approaching the two boundaries, the local fracture energy value decreases continuously. Therefore, the tri-linear model of local fracture distribution can be applied not only to concrete, but also to cement-like materials such as mortar.