加气混凝土墙体的热桥效应及局部保温措施

加气混凝土砌块作为一种能满足寒冷地区65%节能要求的自保温墙体材料,在严寒地区应用时,局部易产生热桥效应,且热桥部位极易产生发霉、冻胀和墙体抹灰层空鼓等问题.本文针对加气混凝土砌块墙体中的外转角及丁字墙部位进行实测,确定了这些部位热桥的影响范围,并分别建立了传热计算模型对温度场进行模拟.同时根据模拟结果设计了热桥部位的局部保温形式,分析了局部保温层厚度和保温层位置对温度场的影响.结果证明,局部保温措施能够提高热桥部位温度,减弱甚至消除热桥的影响,有效抑制墙体内部冷凝及其引发的冻胀冻融现象.研究结果可为加气混凝土砌块自保温墙体在寒区的应用和推广提供理论依据.

Thermal Bridge Effect of Aerated Concrete Wall and Its Partial Insulation

As a self-insulating building material which can meet the 65 percent energy-efficiency requirements in cold regions of China, aerated concrete blocks often go moldy, suffer frost heaving, or cause plaster layer hollowing at thermal bridge parts in extremely cold regions due to the restrictions of environmental climate and construction technique. Outer-corner part and T-shaped part of aerated concrete walls are most influenced by thermal bridge effect. In this paper heat transfer calculation models for outer-corner wall and T-shaped wall were developed, and their temperature fields were simulated. According to the simulation results, insulation measures of the thermal-bridge position of self-heat-insulting walls were designed to weaken or even eliminate thermal bridge effect and to improve the temperature of thermal-bridge position. And the influences of the thickness and location of the local insulation layer on the temperature field were analyzed. Consequently, the condensation inside self-thermal-insulating wall and frost heaving caused by condensation and low temperature were reduced, avoiding damage to the wall body from condensation. The research results can provide theoretical basis for the application and extension of self-thermal-insulating wall in extremely cold regions.