水胶比及骨料粒径对大坝混凝土断裂性能影响的研究

Study on Effect of Water-binder Ratio and Aggregate Size on Fracture Performance of Dam Concrete

文中结合某大坝工程所用混凝土配合比,分别制作5组共20个混凝土试件进行三点弯曲梁断裂试验,分析了混凝土断裂参数在不同水胶比、不同骨料粒径条件下的差异。结果表明,大坝混凝土失稳韧度随所掺加粗骨料粒径的提升而增加,同时其特征长度、断裂能、起裂韧度等性能均表现出前期增长、后期降低的发展趋势;断裂能、失稳韧度和起裂韧度等参数随水胶比增加而降低,混凝土抵抗失稳破坏、开裂、裂缝生成及发展的能力随水胶比增加而降低。

In this paper,based on the concrete mix ratio used in a dam engineering practice,5 groups of 20 concrete specimens were made respectively for three-point bending beam fracture experiment,and the differences of concrete fracture parameters under different water-binder ratio and different aggregate size were analyzed.The results show that the instability toughness of dam concrete increases with the increase of coarse aggregate particle size,and its characteristic length,fracture energy and crack initiation toughness all increase in the early stage and decrease in the later stage.The parameters of fracture energy,instability toughness and crack initiation toughness decrease with the increase of water-binder ratio.The ability of concrete to resist instability failure,cracking,crack formation and development decreases with the increase of water-binder ratio.