Heat and Mass Transfer in the Walls Subjected to Fire

抄録

The physical process of heat and mass transfer in concrete walls was described by a model. The model consist of heat conduction in the skeleton, mass (air, water vapor and adsorbed water) transfer in the pore. The desorption of the adsorbed water and the decomposition of the water of crystallization were included explicitly. The model was applied to two practical problems. The first application was to investigate the variation of insulation performance of flat wall by the change in initial water content. The range of variation was quantified and compared with the variation caused by mix design. From the calculated results, a methodology was proposed to carry out the mix design of concrete for arbitrate required insulation performance taking into account of the variation caused by uncertainty in initial water content. The second application was to define the optimum cross sectional shapes of composite floor of profiled steel sheet and concrete. The model was extensively used to analyze the dependence of the insulation performance upon the cross sectional shape. Simple but useful concept of "thermally optimum" was proposed to assure sufficient insulation performance.