Study On Forming Mould And Process Parameters For Building Block From Rice Straw And Clay

Pressing the straw with clay into farm building blocks is one of the effective ways to utilize waste agricultural resources,which is economical,and socially benefitial.Pressing device were developed in this study and equipped on WDW-200microcomouter controled electronic universal testing machine to compress building block with mixture of rice straw,clay,and water and the effect of straw content,straw length,pressure and other factors on energy consumption and physical and mechanical properties of the blocks were studied.The main conclusion are as follows:(1)An experimental pressing device was developed for compressing mixture of straw clay and water into farm building wall block and stress analysis of key component was carried out with ANSYS and the structure parameters were determined.(2)Single factor and quaternary quadratic regression orthogonal rotation combination ecperimental study on pressing of building wall block of low ratio of straw to clay were conducted factors of moisture content,straw content,straw length and,pressure and indicators of compressive strength,bending strength,recovery rates and energy consumption.The optimal range of each factor and the optimized combination of factors for each indicator were obtained.The optimal parameters combination of factors for each indicator were obtained.The optimal parameters combination for all indicators was obtained through MATLAB analysis as moisture content of 20%,straw content is 1.6%,straw length of90 mm,and pressure of 2.43 MPa,Three replication of verification tests of the optimized parameters were conducted and the results were similar to theoretiacal values.(3)The ternary quadratic regression orthogonal combination experiment of pressi ng building wall block of high ratio of straw to clay was carried out,with factors of straw content,straw length,pressure and indicatiors of compressive strength,bending st rength,recovery rate and power consumption.The mathematical models between factor parameters and indicators were established and the optimal parameters for each indi cator were obtained.The optimal parameters combination for all indicators was obtain ed through MATLAB analysis as straw content of 28%,straw length of 90 mm,and pressure of 8 MPa.Three replication of verification tests of the optimized parameters were carried out and the test results were similar theoretical values.(4)Regression orthogonal experiment on thermal performance of building straw block of high ratio of straw to clay was performed with factors of straw content,straw length and pressure in five levels was indicator of coefficient of thermal conductively.It was concluded that the optimal parameters combination for the coefficient of thermal conductivity were straw content of 40%,straw lengh of 130 mm and pressure of 8.89 MPa.Three replication of Verification tests of the optimized parameters were carried out and the average coefficicent of thermal conductivity is 0.1358 W/(m~2.K),less than0.23 W/(m~2.K),it is a kind of thermal insulation material and it is similar to theoretical value.The results of the study may provide theoretical foundation for the pressing,equipment and application of rice straw building wall blocks.