基于双G准则的掺粉煤灰砼断裂性能研究

Research on Fracture Characteristic of Fly Ash Concrete Based on Dual-G Criterion

采用双G准则研究了掺粉煤灰混凝土的临界能量释放率,采用不同龄期、不同缝高比的掺粉煤灰混凝土梁做三点弯曲试验.试验表明,浇筑之后7d内,随着龄期的增长,临界能量释放率增长;7d后,临界能量释放率几乎不变化,并且不同缝高比对混凝土临界能量释放率影响不大.由此可以得出掺粉煤灰混凝土的断裂参数,并可作为材料的性能指标.

This research focuses on the critical energy release rate of fly ash concrete on the basis of the dual-G criterion. The fracture properties of fly ash concrete at different ages were tested by using threepoint bending beams with different initial crack-depth ratios. The experiment results have indicated that the critical energy release rate grows with time before 7 days. While after 7 days, the critical energy release rate is almost unchanged. And the initial crack-depth ratio has no clear influence on the critical energy release rate. It can be concluded from this research that, for fly ash concrete, fracture parameter can be taken as the indexes in charactering the cracking resistance properties of concrete.