关键词: 开裂特性, 内聚力模型, 多孔结构, 细观尺度, 粉煤灰混凝土

Abstract: With more and more extensive use of fly ash concrete, it is of great importance to study the meso-cracking characteristics of fly ash concrete for optimal design of fly ash concrete. Based on the cohesive zone model, this paper studied the effect of different proportional fly ash and different porosity on the meso-mechanical parameters and cracking of concrete through numerical tests. The results show that with the increase of the content, the influence of the content on the interface elements of mortar is gradually reduced, and the influence on the interface elements of ITZ is gradually increased; the stress concentration phenomenon will form at the internal pores of the fly ash. Cracks develop along the pores and reduce the bearing capacity of the concrete. In the design of concrete, the structure load support capability and economic advantages should be balanced and the admixtures should be selected reasonably.

Key words: cracking characteristic, fly ash concrete, cohesive zone model, mesoscale