混合侵蚀与冻融环境下混凝土力学性能劣化试验

以质量分数为3%的NaCl和5%的Na2SO4混合溶液为侵蚀介质,采用快冻法,对设计强度等级为C30、水灰比分别为0.44、0.50、0.55的混凝土试件进行了0、50、100、150、200次冻融循环试验,测定了各组试件的质量损失、抗压强度、应力、应变等。试验结果表明,混凝土随着冻融循环次数的增多,其表观质量和力学性能均呈现出不同程度的下降趋势,且水灰比越大下降越快。建立了与冻融循环次数相关的力学性能劣化线性方程,为进一步开展混凝土结构在冻融和侵蚀离子共同作用下的劣化机理与计算模型的研究提供了依据。

Experiment of Mechanical Properties Deterioration of Concrete in Multi-aggressive and Freeze-thaw Environment

With mass fraction of 3% NaCl and 5Y0 Na2SO4 mixed solution as aggressive medium, by adopting quick freeze-thaw method, freeze-thaw tests of freeze-thaw cycles of being 0,50,100, 150 and 200 were carried out on concrete specimens. The design strength grade was C30 and the water cement ratio was 0. 44,0. 50,0. 55 respectively. The mass loss, compressive strength, strain and stress and so on were tested. The experimental results show that with the increase of times of freeze-thaw cycles, the apparent quality and mechanical properties decline in different velocities, which is higher when water cement ratio is higher. The mechanical properties deterioration linear equations related to freeze-thaw cycles were established. The result can offer reference for further research on deterioration mechanism and calculation model of reinforced concrete structures in multiple actions of freeze-thaw cycles and aggressive ions.