Optimum Design Analysis Of Multi-row Self-insulating Concrete Composite Block Structure

The traditional concrete block masonry wall is easy to form obvious"hot bridge"in the use process,which causes great energy loss.With the comprehensive promotion and deepening of building energy conservation work in China,it promotes the research and application of new wall materials.This paper combines the scientific research project of Shaanxi Housing and Urban-Rural Construction Department,"Key Technologies and Applications of Passive Low Energy Consumption Architecture Design"?2015K-095?and the scientific and technological plan project of Shaanxi Science and Technology Department,"Research and Development and Application of Low Energy Consumption Green Building Wall Materials"?2016SF-414?,aiming at the comparison of 65%energy saving of self-insulating concrete block walls in GuanZhong area.High requirements,and meet the load-bearing and economic effects in one of the new concrete composite self-insulation block.According to the relevant specifications,the main specifications of concrete self-insulating hollow blocks are selected,which are Selection of main specifications:length×width×height=390mm×240mm×190mm.The structure of concrete self-insulating hollow blocks is optimized by finite element software ABAQUS.The optimized hollow block is made into ceramsite concrete self insulation hollow block,filled with foam concrete optimized by orthogonal test as the thermal insulation material.Through the finite element numerical simulation and experimental research,the multifunctional composite ceramsite self thermal insulation block is finally obtained.The main contents and conclusions of this paper are as follows:1.According to the number of holes,staggered degree and void ratio,12 kinds of hollow blocks with different internal structures are designed.Based on the finite element ABAQUS numerical simulation of heat transfer law of multi-row self-insulating hollow blocks,a general expression for measuring the average heat transfer coefficient of hollow blocks by the length of heat transfer path is derived.According to the analytic hierarchy process,quantitative analysis shows the percentage of thermal performance,mechanical properties and economic benefits that affect the overall performance of self-insulating hollow blocks.2.The averag heat transfer coefficients of 12 hollow blocks are obtained by numerical simulation of thermal performance of 12 kinds of hollow blocks.The maximum difference between the numerical simulation results and the numerical solution obtained according to the code is 6.9%,which verifies the feasibility of the finite element calculation model.Furthermore,the effects of different hole rows,staggered degree and void fraction on thermal performance are obtained,and the general formulaK_{X i}?28?f₁?x _j?×0.412?10?f₂?x _j?×0.588for evaluating heat transfer coefficient with respect to the length of heat transfer path and void fraction is obtained.The mechanical properties of 12 kinds of hollow blocks are obtained.,and the effects of the number of holes,staggered degree and void ratio on mechanical properties were obtained.Through weighted summation optimization,the hollow block with better comprehensive performance is obtained asC₃.The results show that the degree of staggering and the number of hole rows increase to a certain extent,and the degree of staggering and the number of hole rows continue to increase,which has less and less influence on the thermal and mechanical properties of blocks.3.The influence of different mix proportion?cement,fly ash,silica fume and admixture?on the thermal and mechanical properties of foam concrete is explored.The mixing ratio of foam concrete is optimized by orthogonal test,and the influence of various materials on the thermal and mechanical properties of foam concrete is quantitatively analyzed.The optimum ratio isA₅ B₅ C₂ D₄ E₄ F₅,water-cement ratio 41%,fly ash 20%,lithium carbonate 0.16%,polycarboxylic acid water reducer 0.075%,silica powder 4% and calcium carbonate 0.2%.The thermal conductivity and compressive strength of foam concrete are 0.0602W/?m×K?and5.2MParespectively.The stress-strain model of foam concrete under compression failure is obtained.4.The average heat transfer coefficient of ceramsite concrete composite block is obtained by finite element numerical simulation,and the compressive strength of ceramsite concrete composite block is obtained by experiment.The failure law and stress-strain curve characteristics of composite block are explored.At the same time,the optimized block C₃ has the best performance,meets the requirement of 65%energy saving,and obtains the composite self-insulation block with excellent heat preservation,load-bearing and economic benefits.