论文部分内容阅读
荷载与环境因素的耦合作用影响着混凝土内物质传输过程和混凝土结构的服役寿命。为实现短期持续加载和混凝土内水分传输的耦合作用,基于改进的混凝土吸水实时测量装置,对中空圆柱体混凝土试件持续受压加载32 h的同时,按规定时间间隔记录水平观测管内水柱长度的变化,测得混凝土累积吸水量曲线,开展了短期持压荷载作用下低应力水平(0~50%)对混凝土毛细吸水性能影响分析,并根据试验结果建立了相对吸水率与体应变关系。基于扩展Darcy定律的非饱和流体理论(UFT model),采用指数和幂函数两种形式的水力扩散系数,开展了不同应力水平下混凝土中水分分布的预测分析。结果表明:短期持压荷载对混凝土的毛细吸水性能影响显著;在0~50%应力水平范围内,随着应力水平的提高,混凝土的累积吸水量和初始吸水速度先减小后增大,而后期吸水率和水分侵入深度单调增加;根据UFT模型计算的水分渗透深度预测值与实际观测值吻合较好。
The coupling between load and environmental factors affects the material transfer process in concrete and the service life of concrete structures. In order to realize the coupling effect of short-term continuous loading and concrete moisture transfer, based on the improved concrete water absorption real-time measurement device, the hollow cylindrical concrete specimens were subjected to continuous pressure loading for 32 h. At the same time, The curve of cumulative water absorption of concrete was measured and the effect of low stress level (0 ~ 50%) on the capillary water absorption of concrete under short-term pressure load was analyzed. The relationship between relative water absorption and volume strain was established based on the experimental results. Based on the extended Darcy’s law of unsaturated fluid theory (UFT model), exponential and power function of the two forms of the coefficient of hydraulic diffusion, carried out under different stress levels in the distribution of moisture in the concrete to predict the analysis. The results show that the short-term tensile load has a significant effect on the capillary water absorption of concrete. Within the range of 0-50% stress, the cumulative water absorption and initial water absorption of concrete decrease first and then increase with the increase of stress level The water absorption rate and water intrusion depth increased monotonically in the later stage. The prediction value of water penetration depth calculated by UFT model was in good agreement with the actual observation value.