Study On Wet Physical Properties Of Adobe Building Materials

Unfired earth is a common building material of traditional dwellings in many countries.For thousands of years,people have not only built a lot of residential buildings,but also created one after another well-known miracles in the history of architecture.Nowadays,the voice of building an eco-saving,environment-friendly society and seeking the balance between man and nature is constantly increasing.Because of a series of advantages such as energy-saving,environmental protection,comfortable environment and low cost,native buildings have received renewed attention and have a place in the construction market with modern elements.Studying the heat and mass transfer mechanism and wet physical properties of soil envelope structure is of great significance for evaluating the thermal performance,heat and moisture storage capacity of adobe building materials,establishing heat and mass transfer model of adobe envelope structure,optimizing indoor thermal and humid environment of adobe buildings,and reducing heating energy consumption of adobe buildings.On the basis of previous studies,this paper constructs and improves the heat and moisture transfer process of raw soil envelope structure,establishes a one-dimensional heat and mass transfer model of raw soil envelope structure,which provides necessary theoretical preparation for subsequent simulation and analysis of the heat and moisture transfer process of raw soil structure materials.At the same time,a series of experiments were designed to test some basic physical parameters of Yunnan red clay,Yunnan yellow clay and Beijing sand,and the methods of calculating other physical parameters were studied and selected.Subsequently,the wet balance curves of Yunnan red clay,Yunnan loess and Beijing sand were tested.In order to describe the wet balance curve of raw soil materials more accurately,this paper summarizes 8 classical model formulas and uses different models to simulate and analyze the test results.Through the analysis of the simulation results,their applicability is compared from the statistical point of view,and the model suitable for describing the equilibrium moisture curve of raw soil material is selected for subsequent calculation.Based on the equilibrium moisture curve obtained from the experiment,the relationship between the moisture content of raw soil wall and the relative moisture of air in the pore is established.On this basis,the heat transfer and moisture transfer model inside and outside the wall and the mass transfer and heat transfer model between the inner and outer surface of the wall and the indoor and outdoor air are supplemented and improved.Finally,taking Yunnan red clay as an example,the heat and moisture transfer process of unfied soil envelope is simulated.