Study On The Utilization Of Construction Waste Soil In A New-type Stabilized Compressed Earth Thermal Insulated Hollow Brick

With the progress of urbanization construction,the amount of waste soil generated during the construction has increased at a geometric rate.At present,the treatment method for construction waste soil is mainly landfill,supplemented by resource utilization,resulting in a large amount of land be occupied,which caused a severe damage to the ecological environment.The utilization technologies of construction waste soil in new-type stabilized compressed earth thermal insulated hollow brick is set construction waste soil as the main material,through innovative material modification and brick structural design optimization,then combined with modern manufacturing technology to produce innovative energy-saving wall materials.It can provide an important reference for the recycling of construction waste soil and the reduction of energy consumption of buildings.It has important theoretical and practical significance for responding to the country’s call for"protecting the ecological environment and retaining green mountains and green water",to improving the living environment and achieving sustainable social development.Combining experimental research,numerical simulation and theoretical analysis,the main research contents and conclusions of the study are as follows:(1)Through the characteristics analyzation of construction waste soil,it was found that the mineral and chemical composition,particle distribution,plasticity,pH and organic content of construction waste soil would have a greater impact on the selection of brick making technology and product quality.In consideration of energy conservation,environmental protection and manufacture cost,use the neutral or weak alkaline construction waste soil and the cement as the main materials was recommended to produce new-type stabilized compressed earth thermal insulated hollow brick,then the non-sintered semi-dry hydraulic static pressing was used for the forming process of the brick.(2)Through single-factor experimental research,the results showed that the forming pressure,the mixture moisture,the amount of cement and fine stones in the modification of construction waste soil would greatly affect its compressive strength and apparent density.In consideration of material properties and cost control,the ranges of the influencing factors such as forming pressure,mixture moisture,cement and fine stone content had optimal values.According to the analysis of the experimental results,it can be known that the optimal ranges of the above four influencing factors in the construction waste soil modification scheme used in this paper were the forming pressure 15MPa～25MPa,the mixture moisture 10.5%～12.5%,the cement content 8%～12%,and the fine stone content 3%～6%.(3)Through the optimization study of construction waste soil modification based on response surface method,the results show the affect level of the forming pressure,mixture moisture,cement and fine stone content on the apparent density,compressive strength,thermal conductivity,softening coefficient were not the same,and the control factors will have different degrees of interaction on the indicators.The regression model equations of the modified construction waste soil established by the test data combined with the response surface method were experimentally verified to be suitable for the optimization of construction waste soil modification schemes.The error of the indicators’predictive values in this paper was only 6.07%.(4)Through numerical simulation tests of single bricks under different uniaxial axial compression and numerical simulations of steady-state heat transfer for bricks with different structural design.Their differences of the characteristics in compressive strength,strength-to-weight ratio,Mises stress distribution,damage and fracture shape estimation,equivalent thermal resistance,equivalent thermal conductivity of a single brick,wall heat transfer coefficient,thermal resistance weight ratio,heat flow path and heat flow density differences and concerns were analyzed and compared.Considering the mechanical properties,thermal properties,and mold manufacturing costs and other factors,the optimal solution was selected as the brick structure of the new-type stabilized compressed earth thermal insulated hollow brick.(5)The trial production and technical performance test of the new-type stabilized compressed earth thermal insulated hollow brick after material modification and structural design optimization show that the new-type brick has good appearance quality,and its technical performance indicators can meet the technical specifications:The dimensional deviation was not more than 1mm,the apparent density was1192.4kg/m3,the compressive strength was 5.94MPa,the variation coefficient of the compressive strength was 0.02,the water absorption was 7.92%,the relative moisture content was 24.2%,the carbonization coefficient and softening coefficient were 0.87and 0.86,the heat transfer coefficient of the masonry was 1.473W/(m~2?K),and the internal exposure index and external exposure index in the radionuclide limit test were0.3 and 0.5.(6)Through research on production process flow,factory planning layout,equipment selection,product quality control methods and standards,etc.,to ensure the quality of batch products of the new-type stabilized compressed earth thermal insulated hollow brick.Research and analysis on the consistency of masonry or plastering mortar and masonry method,put forward the main points of construction quality control technology,and provide reference for market promotion and application.In summary,the resource utilization technology of construction waste soil in a new-type stabilized compressed earth thermal insulated hollow brick is feasible,and has certain development prospects and application value.