粗砂和细砂砂浆梁无尺寸效应断裂参数的确定
Determination of fracture parameters for coarse sand and fine sand mortar beams without size effect
关键词：
水泥砂浆；抗拉强度；断裂韧度；边界效应模型（BEM）；粗砂；细砂
Key words：
Cement mortar; Tensile strength; Fracture toughness; Boundary effect model(BEM); Coarse sand; Fine sand
刊期：
2025年第10期
DOI：
10.19761/j.1000-4637.2025.10.015.07
文章编号：
基金项目：
国家自然科学基金面上项目（52178259）；山东省自然科学基金项目（ZR2020KA001）。
作者：
陈厚彬，杨树桐*，虞 烜
单位：
中国海洋大学 工程学院，山东 青岛 266000
摘要
摘 要：基于边界效应模型（BEM）确定了无尺寸效应砂浆梁试件的抗拉强度和断裂韧度，通过三点弯曲切口梁断裂试验验证了不同梁高、缝高比、跨高比的粗砂、细砂砂浆梁试件的无尺寸效应，并引入了微观特征参数Cch和离散系数β、C来表示材料的不均匀性和不连续性。此外，还将基于BEM结果与基于传统弹性力学理论试验结果进行了比较。结果表明：基于BEM，只需测得试件的极限荷载，就可以得到无尺寸效应的抗拉强度和断裂韧度；Cch分别取粗砂砂浆的平均骨料粒径和细砂砂浆的平均孔径；基于正态分布分析，得到可靠度为95%的抗拉强度和断裂韧度的上下限；基于BEM所得的断裂参数较基于传统弹性力学理论得到的结果更准确，BEM可以有效解决断裂参数中存在的尺寸效应问题。
Abstract: The tensile strength and fracture toughness of no size effect mortar beam specimens were determined based on the boundary effect model (BEM). Three point bending incision beam fracture tests were conducted to verify the no size effect of coarse sand and fine sand mortar beam specimens with different beam heights, joint height ratios, and span heights. Microscopic characteristic parameters Cch and dispersion coefficients β and C were introduced to represent the inhomogeneity and discontinuity of materials. In addition, the BEM results were compared with the experimental results based on traditional elastomechanics theory. The results show that based on the BEM, the tensile strength and fracture toughness without size effect can be obtained by only measuring the ultimate load of the specimen. Cch is taken as the average aggregate particle size of coarse sand mortar and the average pore size of fine sand mortar, respectively. Based on the analysis of normal distribution, the upper and lower limits of the tensile strength and fracture toughness with the reliability of 95% are obtained. The fracture parameters based on the BEM are more accurate than the results based on the traditional elastomechanics theory, and BEM can effectively solve the problem of size effect in the fracture parameters.
结论
（1）本文利用梁高50 mm组试件的ft来预测其他梁高组试件的极限荷载，预测结果与试验结果吻合较好，说明基于BEM得到的结果无尺寸效应。
（2）本文明确了粗砂砂浆和细砂砂浆Cch的物理意义和取值，并验证了Cch取值的合理性，粗砂砂浆的Cch取平均骨料粒径，而细砂砂浆的Cch取平均孔隙直径。此外，还分别论证了C、β取值的合理性，通过离散系数cv来确定C和β的最佳取值。
（3）将传统弹性力学理论与基于BEM确定的KIC进行比较，传统弹性力学理论得到的KIC有尺寸效应，基于BEM得到的结果更准确。
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引用本文
陈厚彬,杨树桐,虞烜.粗砂和细砂砂浆梁无尺寸效应断裂参数的确定[J].混凝土与水泥制品,2025(10):15-20,26.
CHEN H B,YANG S T,YU X.Determination of fracture parameters for coarse sand and fine sand mortar beams without size effect[J].China Concrete and Cement Products,2025(10):15-20,26.
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