Optimization Of Stabilized Earth Building Material And Analysis On The Thermal Performance Of Earth Wall

Earth material is suitable in rural area which has huge problem of resource and economic shortage as one kind of natural building materials.Its abundant source benefits from direct site-to-service application to reduce the costs.No specialized instrument and specific surroundings are required during the production.This study investigated the majorization of earth building material and improvement on thermal performance of earth wall by both stabilization of earth material and analysis on thermal performance of wall,in the case of Turpan,systematically.Based on the investigation on present situation,indoor environment and living comfort,this study putted forward the typical issues in traditional buildings in Turpan area.Earth building material was stabilized with cement or lime in order to improve the compressive strength and frost resistance of earth material.In addition,the effect of both apparent density and stabilizer content on the properties,i.e.compressive strength,frost resistance,thermal properties and hygroscopic properties,was analyzed.The cause of performance variation of physical properties,which supports the works about stabilization of earth material,was studied by a series of testing,for example structual testing,micromorpholpgy testing and pore structure.The comprehensive evaluation method on properties of earth building material was putted forward to solve the issue that the stabilized earth materials can not to be evaluated by single property.The thermal conductivity,specific heat capacity,equilibrium moisture content were selected as the single index,and the impact point of every single index was determined based on the process of both the heat flux and moisture flux inside the wall.COMSOL Multiphysics was used to calculate the control equation of both the heat flux and moisture flux in order to analyze the effect of single index on the insider surface temperature.The effect was considered as the weight of single index.The properties of the optimazed stabilized earth material were investigated and then compared with comparision samples in order to verify the correctness of the comprehensive evaluation method on stabilized earth material.The optimazed stabilized earth material was sellected as wall material.And the straw insulation was determined as the thermal insulated material.One computer software,Design Builder,was used to eveluate the effect of stabilized earth wall thickness and thermal insulation thickness on indoor hygrothermal environment.The results were indicated that the optimazed thickness of both stabilized earth wall and thermal insulation were determined considering the temperature range of 90 % local residentials acceptable.This study analyzed the variation of indoor hygrothermal environment between straw insulation earth house and fired brick house based on the optimazed thickness of both stabilized earth wall and straw insulation.The results presented that the straw insulation earth house possess better thermal performance in winter and summer than fired brick house.The sited testing of indoor enrironment in demonstration house of new earth residence in Turpan showed that a comfort living condition existed in the demonstration house with no heater and no air condition in both winter and summer.The straw insulation earth wall had a strong thermal performance to decay the effect of ourdoor climate on indoor environment.