水胶比因素影响下水工混凝土湿胀变形试验与模型研究

Experiment and Model Study on the Wet Expansion Deformation of Hydraulic Concrete Considering Water to Cement and Ash Ratios

水工混凝土因其工作环境经常或周期性地受到水的作用,导致混凝土含水量增加从而产生湿胀变形.为研究水胶比与水工混凝土湿胀变形特性的关系,本文根据典型混凝土坝工程不同部位混凝土配合比,设计并开展了不同水胶比的水工混凝土湿胀试验研究.首先通过内埋应变计监测获得试验过程中试件的变形,再建立实测变形的统计模型,反演得到混凝土的热膨胀系数,最后基于浸水后的实测变形分离出湿胀变形分量,并探讨建立考虑水胶比因素的混凝土湿胀变形模型.结果表明:(1)随着水胶比增大,湿胀变形稳定值依次降低,与计算得到的线湿胀系数变化规律一致;(2)本文所提出的湿胀变形组合指数公式与分离出的湿胀变形实测结果拟合效果良好.

Hydraulic concrete is often or periodically subjected to water due to its working environment,and the concrete moisture content is increased to cause wet expansion deformation. To study how the water to cement and fly ash ratios affect wet expansion deformation of hydraulic concrete,four ratios(0.33,0.41,0.50,0.60) are designed based on the mix proportions in different parts of typical concrete projects. Firstly,the samples ’deformation during the test is monitored by embedded strain gauge. Then,statistical model of the measured deformation is established to invert the thermal expansion coefficient of the concrete.Finally,the wet expansion deformation is separated based on the measured deformation after the samples have been submerged in water,and the wet expansion deformation model is established considering the ratios. The results show that:(1) with the increase of the ratios,the stable value of wet expansion decreases,and the calculated linear wet expansion coefficient becomes smaller;(2) the combination index formula of wet expansion fits well with the experimental results.