轴向及偏心压力作用下混凝土抗冻性试验分析

Experimental analysis on frost resistance of concrete under axial and eccentric compression

针对在轴心受压和偏心受压状态下C25混凝土的抗冻性问题,设计了0.4、0.5和0.6三种压应力水平的轴心受压试件及一种偏心受压试件,测算了其预应力损失,通过标准快速冻融循环试验来对比分析抗冻性能.结果表明:所有试件的破坏均达到了相对动弹性模量的限值,而质量损失不明显;轴心受压试件随着应力水平的提高,冻融循环前期抗冻性能逐步增强,但后期损伤速度急剧加快;偏心受压试件与轴心受压试件抗冻性能衰减规律相似,但破坏前受压侧边缘逐步发展了两条主裂缝,导致其抗冻性能快速下降.

Aiming at the frost resistance of C25 concrete under axial and eccentric compression,three axial compression specimens with stress levels of 0.4,0.5 and 0.6 and one eccentric compression specimen were designed,and their prestress loss was measured.Through the standard freeze-thaw cycle tests,the frost resistance was compared and analyzed.The results show that the failure of all specimens reaches the limit of relative dynamic elastic modulus,while the mass loss is not obvious.With the increase of stress level,the frost resistance of axial compression specimen is gradually enhanced in earlier freeze-thaw cycles,but the damage sharply accelerates in later cycles.The attenuation rules of frost resistance for eccentric and axial compression specimens are similar,but two main cracks gradually develop at the pressure edge before failure,leading to rapid decline of frost resistance.