不同冻融介质作用下混凝土力学性能衰减模型

通过快速冻融试验,研究了三种不同冻融介质(水、3.5wt%NaCl、飞机除冰液)对混凝土质量损失、动弹模量以及力学性能的影响,比较了三种冻融介质对混凝土损伤程度的大小,分析了混凝土相对动弹性模量与相对剩余抗压强度和相对剩余抗折强度之间的关系,基于相对动弹性模量建立了相对剩余抗压强度和相对剩余抗折强度衰减方程。结果表明:3.5wt%NaCl溶液对混凝土的损伤度要远大于单纯水冻融循环对混凝土的损伤度,飞机除冰液对混凝土冻融损伤具有抑制作用;混凝土抗压、抗折强度以及相对动弹性模量随着冻融循环次数的增加而降低;三种冻融介质下混凝土抗压、抗折强度损失率大小关系为:3.5wt%NaCl水飞机除冰液;相对动弹性模量与相对剩余抗压强度、相对剩余抗折强度相关性好,可以通过测定混凝土相对动弹性模量来评估混凝土相对剩余强度。

Attenuation model of mechanical properties of concrete under different freezing and thawing

The influence of mass loss,dynamic elastic modulus and mechanical properties of concrete in different solutions (Water,3.5wt%NaCl,Aircraft Deicing fluid)were studied through accelerated cyclic freeze-thaw tests, whose damage degree to concrete was also compared.The relationship between relative dynamic elastic modulus and relative residual compressive strength/relative residual flexural strength was analyzed.Meanwhile,the attenuation equation was also established on account of relative dynamic elastic modulus.The study shows that the freeze-thaw damage to the concrete in 3.5wt%NaCl solution is much worse than in the water,but its damage can be restrained in the Aircraft Deicing fluid.With the increase of the freeze-thaw testing times,the compressive strength,flexural strength and relative dynamic elastic modulus of concrete decrease.The loss ratio of the compressive strength and the flexural strength in different solutions ranges in a descendant sequence is from 3.5wt%NaCl solution to water and then to Aircraft Deicing fluid.The relative residual strength can be evaluated by the relative dynamic elastic modulus due to its good relativity to the relative residual compressive strength and relative residual flexural strength.