Study On Moisture Absorption Characteristics Of Porous Floor

With the improvement of people’s requirements for building environment comfort,it is particularly important to control the temperature and humidity parameters of building environment in a reasonable range.However,there is still a gap between the existing technology of building environment temperature and humidity control and the achievement of this goal.In view of the common floor condensation problem in the transition season and "back to Nantian",this paper takes the existing sintered ceramic permeable brick,concrete permeable brick and sand-based permeable brick on the market as the research object,selects five kinds of porous floor produced by different manufacturers for the evaporation strength test,the whole immersion test,the single-sided immersion test and the moisture absorption test under constant temperature and humidity to study the absorption of porous floor Dehumidification performance.The coupling model of heat and moisture transfer in porous media is established by COMSOL software.By studying the heat and moisture transfer in porous floor under different working conditions,the mechanism of heat and moisture transfer in porous floor which is difficult to measure in the experimental partis supplemented.The related characteristics of moisture absorption in porous floor are studied,and the feasibility of application in foyer in high humidity area in South China is discussed,which is of great significance for building energy conservation.The main research work and conclusions are as follows:(1)The porosity and water retention of five different materials were tested.The porosity of porous floor is 5.2%-15.9%,and the water retention is more than 0.7G / [cm] ^ 2.However,the unilateral water retention is not related to the porosity,which is mainly related to the material composition of porous floor.(2)The experimental results show that the evaporation strength of porous structure has a negative correlation with the water content of the maximum saturated mass.The larger the evaporation strength is,the smaller the water content of the mass when the moisture absorption reaches saturation.The maximum water content of ceramic permeable brick a sintered by ceramsite is 14.78%,which is 3.5 times of that made by concrete,and the moisture absorption rate is 2.99 kg /(m ^ 2 < s ^ 0.5),It is 2.9 times more than that of concrete,which indicates that the moisture absorption property of ceramsite is the best.(3)Compared with water absorption experiment and moisture absorption experiment,the results show that the moisture absorption rate of porous floor is less than the water absorption rate,and it takes a long time toreach the moisture absorption balance.Concrete specimen B can continue to absorb moisture for 48 hours in 95% high humidity environment,but still can not reach the balance,which shows that the moisture absorption capacity of concrete and quartz sand is strong,but the water retention capacity is weak.By changing the material ratio,the moisture absorption rate of porous floor is lower than that of water absorption rate To increase the moisture absorption and water retention performance of porous floor.(4)The results show that the thermal conductivity,the vapor diffusion coefficient and the vapor permeability coefficient all increase with the increase of the external temperature,but the vapor diffusion coefficient increases with the increase of the humidity,and the rate of increase slows down.The temperature can promote the expansion of the humidity to a certain extent Under the condition of different relative humidity,the change of humidity gradually increases with the increase of external humidity.The higher the humidity is,the greater the speed of humidity diffusion at the initial time is.Under the condition of 95% humidity,the speed of humidity diffusion increases linearly.Different materials have obvious influence on the heat and humidity transfer.The greater the thermal conductivity of materials,the faster the temperature transfer,the faster the humidity transfer.Quartz sand materials The heat and moisture transfer is much faster than that of concrete.The above research results show that porous permeable brick has goodmoisture absorption and desorption performance.On this basis,can we reduce organic compounds in the design of material ratio,and inhibit the growth of mold by adding additives such as zinc oxide and titanium dioxide.For how to develop better moisture absorption materials,we can increase its aesthetic performance and moisture absorption performance by coating a layer of nano coating on the surface of porous floor It has important guiding significance.