Optimization Of Proportion Earth Modified Wall Material And Analysis On The Thermal And Humidity Properties

The soil material is regarded as a green building material with renewable,low cost,local materials and simple preparation process.In this paper,the soil material was taken from Jinfeng district of Yinchuan city,Ningxia,and the modification of soil material and the evaluation of thermal and wet comprehensive properties were studied systematically.In view of the defects existing in the compressive strength of soil materials,this paper firstly analyzes the influence of mineral composition,particle size distribution and water content on the compressive strength of soil materials,and tests the compressive strength value of soil materials under different water content through experiments.The results show that when the moisture content is 13%,the compressive strength of soil material reaches the maximum value of 1.61 MPa.Using cement,lime and fly ash as modifiers,soil modified wall materials were prepared through orthogonal experimental design.Range analysis was used to analyze the variation rule and influence of the modifier content on the thermal and wet properties of soil modified wall materials.Then,due to a single index is not comprehensive in evaluating the thermal and humidity comprehensive performance of soil modified wall materials,this paper calculates the weight of three single evaluation indexes,namely thermal conductivity coefficient,specific heat capacity and isothermal equilibrium moisture content,based on the governing equation of heat and mass transfer of the wall.Among them,COMSOL Multiphysics was used to solve the governing equation of heat and mass migration.The influence of each single evaluation index on the inner surface temperature of the wall was taken as its weight value to obtain the mathematical model for the comprehensive evaluation of heat and humidity performance of soil modified wall materials,so as to determine the optimal mix ratio is cement content of 7%,lime content 8%,fly ash content 10% and moisture content is10%.Soil was optimized by using infrared spectroscopy and electron microscope scanning test modified wall structural composition and microstructure of materials,through the thorough analysis,soil is expounded from the aspects of the mechanism of modified wall materials thermal and moisture properties boost,the results show that because of the carbonization reaction of lime and cement,fly ash produced by the hydration reaction of gel product in raw soil material form compact overall structure,the structure of pore not only reduce the modification coefficient of thermal conductivity of wall materials,thesoil also increased the moisture absorption properties of the material.