模拟酸雨环境下混凝土抗拉性能试验研究

为揭示酸雨环境下混凝土抗拉性能的变化规律,在实验室配置了pH1.0硝酸硫酸混合溶液来模拟酸雨环境,采用完全浸泡的加速腐蚀试验方法对40个哑铃形混凝土试件进行不同程度的腐蚀,完成了受侵蚀不同程度的混凝土单轴拉伸试验.结果表明:在腐蚀初期,混凝土的抗拉强度、弹性模量和峰值应变逐渐递增;随腐蚀时间的延长,抗拉强度和弹性模量逐渐降低,但峰值应变仍继续增长;在相同环境下,混凝土抗压强度对腐蚀环境的敏感性较抗拉强度的敏感性大.基于试验结果,提出了酸雨环境下混凝土单轴抗拉应力-应变曲线上升段统一数学表达式.

Experimental Study on Tensile Mechanical Properties of Concrete

The aim of this paper is to investigate the uniaxial tensile property of concrete exposed to the acid rain environment. Acid solution with pH value of 1.0 was prepared by the mixture of sulfate and nitric acid solution in the laboratory. Fourty dumbbell shaped concrete specimens were immersed in the simulated acid solution completely. After being exposed to the simulated acid mixture for a certain period, uniaxial tensile test were performed on the concrete specimens. It is shown that elastic modulus, tensile strength and peak strain have a slight increase at the initial corrosion stage, and with the extension of corrosion process, elastic modulus and tensile strength decrease gradually, while the peak strain still increases. It is found that the compressive strength is more sensitive to aggressive environment than the tensile strength. Based on the experimental results, an equation was established to describe the ascending part of the stress strain curve of the concrete exposed to acid rain environment.