Study on Size Effect Law of Compressive Strength of Building Mortar under Uniaxial Compression

DOI：

 作者 单位 杨伟军，袁帅，杨春侠 （长沙理工大学 土木工程学院，湖南 长沙，410114）

为评估尺寸效应行为对砂浆准脆性材料力学性能的影响及完善砂浆尺寸效应理论，以物理模型试验方法及理论解析方法对砂浆尺寸效应行为进行了研究. 通过对12组几何相似的砂浆立方体试件及12组非几何相似的砂浆板式试件进行单轴抗压强度试验，研究砂浆尺寸效应行为及砂浆强度等级对尺寸效应的影响. 研究结果表明，砂浆抗压强度随着试件几何尺寸的增大而减小，尺寸效应随砂浆强度等级的提高而增强. 引入基于断裂力学能量释放理论尺寸效应律分析砂浆几何相似试件的尺寸效应行为，加入强度项修正Bazant尺寸效应律并以修正尺寸效应律分析砂浆非几何相似试件的尺寸效应行为，分别建立了砂浆抗压强度尺寸效应律计算式，其计算结果与试验结果吻合良好. 该研究成果可为砂浆材料工程应用提供指导，为砌体精细化细观模型的建立提供重要依据.

In order to evaluate the size effect on the mechanical properties of mortar and to improve the size effect theory of mortar, size effect behaviours of mortar were investigated by using test method and theoretical analysis method. Based on the uniaxial compression test on 12 groups of mortar cube specimen and 12 groups of motar plate specimen, the size effect behaviour of mortar specimen and the relationship between mortar strength grade and size effect of compressive strength were investigated. The results indicate that the mortar compressive strength decreases with the increase of the specimen size, while the degree of size effect is enhanced with the increase of mortar strength grade. The energy release based size effect law was introduced to study the size effect of mortar geometrically similar specimen. The size effect of the mortar specimen of non-geometric similarity was also analyzed by correcting the Bazant size effect law with adding intensity term. Finally, the mortar size effect laws which can predict the size effect behavior of geometrically similar specimen, as well as the non-geometrically similar specimen，are derived，respectively. The predicted results of the proposed size effect law match well with test data. The research results provide an important basis for the establishment of the fine microscopic model of masonry, and also provide guidance for the engineering application of mortar.