恒定气候环境下表面裂缝对混凝土内部湿度响应的影响

为了研究开裂混凝土内部微环境与外部环境的湿度响应关系,通过人工模拟恒定气候环境,开展了不同裂缝工况下混凝土内部湿度响应试验,并考虑了不同水灰比和不同粉煤灰掺量的影响; 提出了考虑表面裂缝影响的混凝土等效湿气扩散系数计算公式,建立了恒定气候环境下带表面裂缝混凝土内部湿度响应预测模型,并验证了模型的可行性。结果表明:有裂缝混凝土内部湿度响应速率高于无裂缝混凝土,在裂缝工况下,混凝土湿度响应速率随裂缝宽度的增加变化不明显,随裂缝深度的增加呈线性增大; 有裂缝混凝土内部湿度响应速率随水灰比的增大而增大,无粉煤灰的普通混凝土试件内部湿度响应速率依次大于30%和15%粉煤灰掺量(质量分数)试件; 裂缝在不同水灰比及不同粉煤灰掺量下对混凝土内部湿度响应的影响程度有所不同。

Influence of Surface Cracks on Humidity Response of Concrete Under Constant Climatic Environment

In order to study the humidity response relationship between the internal micro-environment and the external environment of cracked concrete, the internal humidity response tests of concrete under different crack conditions were carried out by artificially simulating the constant climatic environment, and the effects of different water cement ratios and fly ash contents were also considered. Finally, a formula for calculating the equivalent moisture diffusion coefficient of concrete considering the effect of surface crack was proposed, and the prediction model of internal humidity response of concrete with surface crack under the constant climatic environment was established, then the feasibility of the model was verified. The results show that the internal humidity response rate of cracked concrete is higher than that of non-cracked concrete. Under the crack conditions, the humidity response rate of concrete does not change significantly with the increase of crack width, but increases linearly with the increase of crack depth. The humidity response rate of cracked concrete increases with the increase of the water-cement ratio, and the humidity response rate of concrete without fly ash is the fastest, followed by the concrete with the fly ash content of 30% and 15%. Moreover, there are differences in the significance of the effect of cracks on the internal humidity response of concrete with different water-cement ratios and fly ash contents.