基于内聚力模型的粉煤灰混凝土细观开裂研究

随着粉煤灰混凝土越来越广泛的使用,研究粉煤灰混凝土的细观开裂特性对于粉煤灰混凝土优化设计具有非要重要的意义。以内聚力模型为基础,通过数值试验的方法研究了不同粉煤灰掺量和不同孔隙率对混凝土细观力学参数和开裂的影响。研究结果表明:随着粉煤灰掺量的增加,掺量对砂浆界面单元的影响程度逐渐降低,对ITZ界面单元的影响逐渐增强;粉煤灰混凝土内部孔隙处会形成应力集中现象,微裂纹沿着孔隙发展,降低了混凝土的承载能力。在混凝土的生产设计中,应平衡结构承载能力和经济要求,对掺合料的种类和用量进行合理选择。

Research on meso-cracking of fly ash concrete based on cohesive zone model

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.