碳化及硫酸盐侵蚀对混凝土强度性能的影响研究

为研究碳化与硫酸盐侵蚀共同作用下混凝土的强度特性及其演变规律,分别通过单一硫酸盐干湿循环试验、单一碳化试验以及碳化与硫酸盐干湿循环的交替试验,分析其对混凝土强度特性的影响机理。试验结果表明:水灰比越小,单一硫酸盐侵蚀以及碳化与硫酸盐侵蚀交替作用后混凝土的抗压强度及劈裂抗拉强度降低幅度越小;随着碳化时间的延长,混凝土的抗压强度及劈裂抗拉强度呈现先快后慢的增长趋势,且水灰比越大,增长幅度越大;碳化与硫酸盐侵蚀共同作用下,二者对混凝土强度的影响特征并非各自影响效应的简单叠加,而是相互影响、相互促进。因此,在碳化和硫酸盐侵蚀作用同时存在的环境中,混凝土的水灰比不应太大。

Study of the influence on the concrete strength properties of carbonation and sulfate corrosion

In order to study the strength characteristics and evolution law of concrete under the combined action of carbonization and sulfate attack, the influence mechanism of the strength characteristics of concrete is analyzed by means of single sulfate wetting-drying test, single carbonization test and carbonization and sulfate wetting-drying alternate test. The test results showed that: the smaller the water cement ratio is, the less the compressive strength and splitting tensile strength of the concrete are when the single sulfate attack and the interaction of carbonization and sulfate corrosion have taken place.With the increase of carbonization time, the compressive strength and splitting tensile strength of concrete begin to increase at first and then slowly, and the larger the water cement ratio is, the greater the growth rate is.Under the combined action of carbonization and sulfate attack, the influence of the two on the strength of concrete is not a simple superposition of their respective effects, but they affect each other and promote each other. Therefore, in the environment where carbonation and sulfate attack exist simultaneously, the water cement ratio of the concrete should not be too large.