The Research On Attenuation Characteristics Of Moisture Content In New Building Palisade Structure

Building envelope materials used are porous media, within which contains morepores and its internal easily have wet air, liquid water and solid ice. Environment insidethe building transfer constantly wet and heat through the building envelope and theexternal environment, so in addition to the outdoor environment, the heat and moistureconditions of building envelope had a very important impact on the indoor environmentand building energy consumption. The research on the factors of affecting on theenvelope the structure transferring heat and moisture had more and more at home andabroad.Recently, the research on Heat and Moisture transfer within the building envelopeat home and abroad mostly for the quasi-steady-state, which was built in a certain time,and less research on the moisture transfer and change inside the newly constructedbuilding envelope. As the newly constructed buildings have high moisture content built,in the early decay of the building envelope moisture content within a certain time afterthe completion of building have a significant impact on the insulation performance ofthe building envelope materials, indoor environment, the wet accumulation of theinternal structure, cooling and heating load of the building. So it is very important forthe study of the decay of the moisture content after the completion of new buildings.In this paper, based on the division of the climate zone, we select the sintered claybrick wall, aerated concrete walls and reinforced concrete EPS wall in the three regionsin Xi’an, Changsha, Guangzhou as the research object, through the establishment of thewall heat and moisture transfer model, which simplify think of the heat and moisturetransfer of the wall was the one-dimensional passing. The attenuation of the wall moisture content from new wall built to wet stable was simulated by heat and moisturetransfer calculation software--CHAMPS. By calculating we mainly obtained the changerate of the moisture content in the new wall, the distribution of the internal moisturecontent, change time of the moisture content and stable moisture content. Meanwhile,we analysed the factors of impacting the new wall moisture content from the initialmoisture content, the thickness of the wall, the indoor wet environment and the wallstructure type.According to the numerical calculation result, we found that sintered clay brickwall after4.66years,2.15years,2.05and aerated concrete wall after2.43,2.08,2.22,achieved wet stable in Xi’an, Changsha, Guangzhou. Reinforced concrete EPS wall after10.98,8.02achieved wet stability in Xi’an and Changsha. Results analysis showed thatreinforced concrete EPS wall in the same area three wall wet stable time was the longest.For new wall, the initial moisture content only impacted on the moisture contentchanges within the predetermined time. The greater the initial moisture content, themore obvious attenuation. The decay time of moisture content in new wall increasedwith the thickness of the wall increasing within a certain range, wherein the wetstabilization time of sintered clay brick wall was significantly increased with thethickness increasing, while the wet stable time of the aerated concrete wall increasedlinearly with the thickness increasing.The stable moisture content in the reinforcedconcrete EPS wall was significantly affected by the indoor relative humidity.