免拆模板-混凝土复合墙体早龄期热湿耦合传递特性研究

Simulative study on coupled heat and moisture transfer in permanent formwork-concrete composite wall during the early age period

以免拆模板-混凝土复合墙体为研究对象,考虑早龄期混凝土水化反应的影响,以毛细压力和温度为驱动势,构建多层墙体一维瞬态热湿耦合传递模型,利用COMSOL Multiphysics模拟研究该复合墙体在早龄期的热湿传递过程。结果表明:水化反应对复合墙体早龄期热湿特性有重要影响,忽略水化反应会低估复合墙体的温度、高估其湿度。考虑水化反应时,复合墙体中混凝土在前期温升较大、湿度降幅较大。与忽略水化反应的情况相比,前期混凝土含湿量梯度更小、梯度范围更大。与忽略水化反应相比,免拆模板在水化反应早期温度、湿度波动较大。免拆模板具有一定保温隔热和湿缓冲能力。

This paper takes permanent formwork-concrete composite wall as research objects.In considering the influence of hydration reaction of early-age concrete,a one-dimensional transient hygrothermal model for multilayer wall structures which uses the temperature and capillary pressure as the driving potentials was established.Using COMSOL Multiphysics simulation to study the heat and moisture transfer process of the composite wall at early age.The results show that the hydration reaction has a significant impact on the early age heat and moisture characteristics of composite walls,ignoring the hydration reaction of early-age concrete will underestimate the internal temperature of permanent formwork-concrete composite wall and overestimate its humidity ratio.When considering the hydration reaction,the concrete in the composite wall has a significant temperature rise and humidity decrease in the early stage.Compared with ignoring the hydration reactions,the moisture content gradient of concrete in the early stage is smaller and the gradient range is larger.Compared with ignoring hydration reactions,permanent formwork exhibit significant temperature and humidity fluctuations in the early stages of hydration reactions.The permanent formwork has certain insulation and moisture buffering capabilities.