冻融循环作用下混凝土构件受压性能损伤试验研究

EXPERIMENTAL RESEARCH ON COMPRESSIVE DAMAGE OF CONCRETE MEMBER UNDER FREEZE-THAW CYCLES

混凝土结构的冻融破坏是寒冷地区经常发生的自然灾害,冻融引起的混凝土结构的耐久性问题已不容忽视。在混凝土材料的抗冻耐久性研究的基础上,从构件层面上对冻融循环作用下混凝土强度等级C30、对称配筋的受压构件柱进行快速冻融试验,观察冻融作用后混凝土受压柱破坏的外观形态、质量损失与动弹性模量的变化,以及受损后的混凝土柱抗压性能的变化。试验结果表明：混凝土构件的冻融破坏与冻融循环次数有关,冻融循环作用次数越多,构件破坏越严重,其单轴受压承载力也随之降低,尤其是在冻融循环数达100次以后,构件性能劣化加剧。混凝土构件在轴向加载过程中,破坏形式呈混凝土压碎破坏。最后,建立了冻融循环作用后混凝土构件受压承载力的计算模型。

Freeze-thaw damage of concrete structures often happens in cold areas,the problems of structure durability caused by freeze-thaw cycles can not be ignored. On the basis of frost resistance durability research on concrete materials,the fast freeze-thaw experiments on the symmetrical reinforcement compressed column whose strength grade of concrete was C30 were conducted, the appearance,mass loss ratio and dynamic elasticity modulus of the compressive concrete column under freeze-thaw cycles were observed,as well as the compressive property of damaged concrete column. The experimental results showed that the damage degree was related to the times of freeze-thaw cycle,the more times,the more serious of the damage was,and its uniaxial compression bearing capacity was also reduced,especially after 100 times of freeze-thaw cycles,the degradation of the member performance was aggravated.In the process of the axial loading,the failure mode was concrete crushing,a compression bearing capacity calculation model of the concrete member under freeze-thaw cycles was established.