Preparation And Properties Of Humidity-controlling Building Materials With Water Resistance

Humidity-controlling materials are the materials that don't require any artificial energy or mechanical equipment to adjust the air relative humidity automatically relying on their own performance of absorption and desorption.The suitable indoor relative humidity for living is 40%⁶0%while the relative humidity will be fluctuating and go far beyond that in the middle and lower reaches of the Yangtze river,which has a serious impact on people's health and comfort.The building energy consumption will be increased relying on air conditioning dehumidification.Therefore,there is a great significance to prepare humidity-controlling materials with high strength,good water resistance and excellent humidity-controlling performance through low energy consumption and clean process.The natural pore structure of three inorganic mineral materials,diatomite,zeolite and sepiolite,is used in this paper.There is a modification of inorganic mineral admixture to prepare humidity-controlling materials with high strength and good water resistance based on inorganic minerals.Then the capability of humidity-controlling of the composite mineral materials is improved by the modification of sphagnum.The experiment on the effect of indoor temperature and humidity control is studied.Preliminary exploration is made for the preparation and application of humidity-controlling building materials with water resistance.The result shows that:1)The best content of inorganic modified admixture is 15%²5%.The compressive strength of the materials is greater than 5.5 MPa.The softening coefficient is greater than 0.56.The maximum equilibrium moisture content is more than 12.38%.The absorption rate is greater than 0.0350Kg/Kg·d.The desorption rate is greater than 0.0290Kg/Kg·d.The?-C₂S in the modified admixture can react with water to produce Ca?OH?₂ and C-S-H gels.In alkaline environment,Ca?OH?₂ and MgO reacted with SiO₂ and Al₂O₃ in diatomite,zeolite and sepiolite to produce compounds with strength and water resistance.2)The best content of sphagnum is 5%¹3%.The compressive strength of the materials is greater than 6.1 MPa.The softening coefficient is greater than 0.54.The maximum equilibrium moisture content is more than 14.70%.The absorption rate is greater than 0.0436Kg/Kg·d.The desorption rate is greater than0.0318Kg/Kg·d.The maximum equilibrium moisture content is increased by 17%to 65%.The maximum absorption and desorption rate is increased by 3%to 68%.Inorganic minerals are mixed with sphagnum and filled in the sphagnum fiber.Depended on the unique microporous structure of sphagnum,the equilibrium moisture content of the sphagnum based compound humidity-controlling materials are increased.It also provides a smooth channel for the entry and exit of water molecules,which improves absorption and desorption rate.3)Considering the average relative humidity indoor and relative humidity difference,the thickness of diatomite spraying should be 0.5mm¹mm.The indoor relative humidity can be maintained at 45%⁶0%and the fluctuation of indoor humidity is less than 10%.Diatomite humidity-controlling materials have good indoor temperature and humidity regulation effect,effectively relax the indoor relative humidity fluctuation.There is a good application value in regulating indoor relative humidity in the southern humid and hot area.