Study On Transmission Characteristics Of Coupled Heat And Moisture Transfer Of Cast-in-place Concrete Wall With Thermal Insulation Free From Demolition Template

The cast-in-place concrete wall without dismantling the insulation template is a new wall technology that integrates insulation and structure,and is a new direction of development in the field of building energy conservation technology.It has been increasingly widely used in practical engineering.However,the current research on the coupled heat and moisture transfer characteristics in different climate regions is not yet complete,and it is urgent to carry out relevant research to provide a basis for energysaving structure optimization and moisture-proof design,and promote the promotion and application of non dismantling insulation formwork cast-in-place concrete walls.By combining theoretical analysis,experiments,and numerical simulation calculations,experimental tests were conducted on the heat and moisture transfer performance parameters of C40 concrete and polystyrene particle insulation mortar,which are the components of cast-in-place concrete walls without dismantling insulation templates.The heat and moisture coupling transfer law inside the walls was studied,and the heat and moisture coupling transfer characteristics inside the walls of three typical cities in cold regions,hot summer and cold winter regions,and hot summer and warm winter regions were obtained,The main research results are as follows:1)A coupled heat and moisture transfer model for cast-in-place concrete walls with non dismantling insulation templates was established,driven by temperature and relative humidity.The model includes heat and moisture transfer equations,and the required heat and moisture transfer performance parameters for numerical simulation calculation are determined as follows: dry density,thermal conductivity,moisture characteristic curve,moisture diffusion coefficient,and water vapor diffusion coefficient.2)We have developed a test plan for the heat and moisture transfer performance parameters of the components of the cast-in-place concrete wall with a non dismantling insulation template,and conducted experimental tests on the heat and moisture transfer performance parameters of the components of C40 concrete and polystyrene particle insulation mortar.The experimental tests obtained the heat and moisture transfer performance parameters of two wall materials,including dry density,porosity,thermal conductivity,moisture characteristic curve,moisture diffusion coefficient,and water vapor diffusion coefficient.The functional relationship between the equilibrium moisture content and the equilibrium relative humidity,as well as the functional relationship between the thermal conductivity coefficient and the equilibrium moisture content,were obtained The functional relationship between water diffusion coefficient and equilibrium moisture content,and the functional relationship between water vapor diffusion coefficient and equilibrium relative humidity,studied the heat and moisture coupling transfer law inside the wall.3)In the laboratory environment,the temperature and humidity distribution inside the cast-in-place concrete wall with non removable thermal insulation formwork was tested for 10 days.On the basis of the test,the heat and humidity coupling transfer law inside the wall was studied.The temperature and humidity inside the wall exhibit irregular periodic changes due to external influences.The measurement points near the wall boundary are more significantly affected by the external environment,and the waveform of the changes is similar to the external environment.The temperature and humidity fluctuations at the internal measurement points have varying degrees of attenuation delay characteristics;The maximum absolute error of temperature at different thickness positions is 2.17 ℃,the maximum relative error is 11.43%,the minimum relative error is 6.41%,and the maximum average relative error is 9.17%;The maximum absolute error of humidity is 0.0814,the maximum relative error is13.74%,the minimum relative error is 5.33%,and the maximum average relative error is 13.25%.Both have a high degree of coincidence.The relative errors of temperature and relative humidity are within the allowable range of the project.4)Taking Xuzhou,a cold region,Shanghai,a hot summer and cold winter region,and Guangzhou,a hot summer and warm winter region,as examples,numerical simulation calculations were conducted on the coupled heat and moisture transfer characteristics of cast-in-place concrete walls with non removable insulation templates in three regions.The simulation results show that the temperature and humidity changes on the inner and outer surfaces of the wall are basically consistent with the temperature and humidity changes in the indoor and outdoor environment.The fluctuation amplitude of the center of the wall is relatively small,and there is a lag in the peak and valley,reflecting the characteristics of attenuation and delay.There is no risk of condensation on the cast-in-place concrete walls with detachable insulation templates in three cities,but they all have varying degrees of mold formation.Necessary moistureproof measures should be taken in advance.There are 106 pictures,27 tables and 89 references.