紫外线辐射及冻融循环双因素下面板混凝土力学性能研究

为了建立考虑紫外线辐射作用的混凝土冻融循环损伤模型,有必要弄清紫外线辐射与冻融循环相结合条件下对面板混凝土力学性能的影响。为此进行了紫外线辐射试验、冻融循环试验和混凝土抗弯强度试验,并对混凝土试件表面状况、质量损失率和抗弯强度进行了对比分析。试验结果表明:在一定冻融循环次数下,水灰比越大,质量损失率越大。相较于未经紫外线照射的对照组,经过紫外线照射的试件在经过一定循环次数的冻融后,其质量损失率更大。紫外线辐射对低强混凝土的质量损失率影响主要是在冻融循环的早期表现出来,而对高强混凝土则是在冻融循环的晚期表现出来。紫外线辐射对经受冻融循环后的混凝土抗弯性能没有明显的影响,在其他条件相同的情况下,水灰比越低,抗弯强度越高。

Study on mechanical properties of facing concrete under dual-factor of ultraviolet radiation and freeze-thaw cycle

In order to establish the freeze-thaw cycle damage model of concrete under consideration of the effect of ultraviolet radiation，it is necessary to know the influence from the combination of ultraviolet radiation and freeze-thaw cycle on the mechanical properties of facing concrete. Therefore，the ultraviolet radiation experiment，freeze-thaw cycle experiment and concrete flexural strength experiment are carried out，and then the comparative analyses are made on the surface condition，mass loss rate and flexural strength of concrete specimens. The experiment result shows that under a certain number of freeze-thaw cycles，the larger the water-cement ratio is，the greater the mass loss rate is to be. Compared with the control group without the ultraviolet irradiation， the mass loss rates of the specimens through ultraviolet irradiation after certain freeze-thaw cycles are more greater. The effect of ultraviolet irradiation on the mass loss rate of low-strength concrete mainly exhibits in the early stage of the freeze-thaw cycle， while it is exhibited in the later stage of the freeze-thaw cycle for the high-strength concrete. There is no significant effect from ultraviolet irradiation on the flexural performance of the concrete after freeze-thaw cycle，for which the lower the water-cement ratio is，the flexural strength is to be higher under the other same conditions.