Study On Hygro-thermal Characteristics And Application Of Novel Cement-cork Mortars

Rational utilization of renewable industrial wastes is an important way to reduce the consumption of building materials.Wood industry waste cork particles is a kind of renewable and sustainable lightweight aggregate,which shows low density,low thermal conductivity,good sound absorption and water resistance,and is cheap and easy to obtain.Therefore,this article guarantees the cement mortar compressive strength standard foundation,through the cork particle replaces the sand in the cement mortar to improve its heat wet performance,and carries on the analysis to the new cork cement mortar on the application of the building wall,provides the basis for the new cork cement mortar’s popularization and application.In this paper,cork mortar specimens(M0～M50)were prepared by replacing the volume of sand in cement mortar with volume ratios of 0%,10%,20%,30%,40% and50% of cork particles.The fluidity,compressive strength and microstructure characterization of the new cork cement mortar were obtained through experimental tests.The effects of temperature and wet composition on the thermophysical parameters of cork cement mortar(thermal conductivity,specific heat capacity,heat storage coefficient,thermal diffusion coefficient)were obtained by using transient test method.In the process of moisture balance,the isothermal moisture absorption curve of cork cement mortar was also obtained.The liquid water diffusion coefficient and water vapor permeability coefficient of cork cement mortar were obtained by partial immersion method and desiccant method respectively.Finally,the heat and moisture transfer characteristics and the influence on energy consumption of cement mortar with different cork content applied to the building wall were obtained by numerical calculation.The specific conclusions are as follows:(1)The compressive strength of cork cement mortar decreases with the increase of cork particles,compared with the mortar with no cork content,the compressive strength of the mortar with 50% cork content decreases by about 66.2%,but the minimum compressive strength is 7.72 MPa,which still meets the standard requirements of masonry mortar and plastering mortar.With the increase of cork content,the fluidity of mortar mixture has no obvious change,and the consistency of M0 ～ M50 fluctuates around 35 mm.(2)When the cork content increases from 0% to 50%,the thermal conductivity of cement mortar decreases by about 52.5%.When the temperature increases from20℃ to 70℃,the thermal conductivity of M50 increases the most(7.5%),and the thermal diffusivity of M30 decreases the most(16.6%).With the increase of wet composition,the thermal conductivity,specific heat,heat storage coefficient and thermal diffusion coefficient of M0 to M50 increase in the range of 57.8% ～ 60.7%,14.1% ～ 26.7%,39.9% ～ 46.2% and 20.3 ～ 48.7%,respectively.(3)Compared with the mortar without cork content,the water absorption coefficient and liquid water diffusion coefficient of the mortar with 50% cork content decreased by about 76.5% and 87.9%,respectively.Compared with M10,the decrease rate of water vapor permeability coefficient of M20 is about 71.3%,compared with M20,the growth rate of water vapor permeability coefficient of M50 is about 88.9%.(4)After the application of cork cement mortar to buildings,the heat and moisture transfer performance of walls and building energy consumption will be reduced.Compared with M0,the total heat flow of M50 decreased by about 38.2% and the total wet flow decreased by about 90.4%,and the maximum change rate of the total daily energy consumption from M0 to M50 is 40%.Through the above analysis,the new type of cork cement mortar heat coupling transmission calculation provide detailed thermal physical parameters,obtained the new thermal physical parameters of cork cement mortar respectively by the rule of variation of temperature and moisture content,the new cork cement mortar is obtained by numerical simulation is applied to the building wall insulation after wet insulation performance,hope for the popularization and application of new cork cement mortar provides the basis of thermal parameters and theoretical support.