Effect Of Ceramsite On Concrete Performance Of Shear Wall In Hot Summer And Warm Winter Zone

As a lateral force resistance component to resist the horizontal load effectively,reinforced concrete shear walls are widely used in the structural system of high rise buildings.In hot summer and warm winter zone.Based on the requirements of building energy conservation standards,design,checking and testing of the shear wall system must be carried out for heat insulation and preservation,external insulation is a common thermal insulation technology for shear wall.However,the safety issues caused by difference in performance and service life between the main structural material of reinforced concrete shear walls and lightweight low-strength external insulation materials are worrying.There are many typhoons in the southeastern Fujian of hot summer and warm winter zone,so the lightweight and low-strength external insulation materials are more vulnerable to damage.In this paper,we replace ordinary coarse aggregate in shear wall concrete with appropriate proportions and the same volume ceramist,which not only ensures the concrete strength to meet the design requirements of shear wall,but also reduces the thermal conductivity of concrete,so it can reduce the heat transfer coefficient of reinforced concrete shear wall significantly,and reduce requirements of external thermal insulation materials in shear wall system to some extent,and provide space for increasing strength and durability of external insulation materials.The detailed contents and results are follows:(1)Experimental research on the influence of the replacement rate and density of ceramsite on the compressive strength and thermal conductivity of concrete.Results illustrate that:Considering the concrete cubic compressive strength and thermal conductivity synthetically,we determine to use 700density grade ceramsite to replace 60%coarse aggregate as the concrete mix ratio;when the replacement rate of ceramsite is 60%,the thermal conductivity of ceramsite concrete with a density rank of 700 is 0.6745W/m·K,and the strength level is C35.(2)Test on wall heat transfer coefficient.Results illustrate that when 700grade ceramsite is replaced by 60%coarse aggregate of the same volume,the heat transfer coefficient of reinforced concrete shear wall decreases from 3.16W/(m~2·K)to 1.92 W/(m~2·K)with a decrease rate of 39.2%.(3)Experimental research on the influence of the replacement rate of 700grade ceramsite on axial compression strength and stress-strain curve.Results illustrate that under vertical load,the ceramsite becomes weak interface of concrete damage,the replacement rate of ceramsite has a direct effect on the failure mode of concrete;As the increase of ceramsite replacement rate,the apparent density of concrete have a linear decrease,elastic modulus of concrete decrease and Poisson's ratios increase;the calculation formulas of constitutive equation and elastic modulus of ceramsite concrete under different replacement rate is obtained by fitting.(4)Using ABAQUS finite element software to research the effect of 700grade ceramsite replacement rate on the main mechanical properties of shear walls,results show that the bearing capacity of shear wall is reducedas the increase of ceramsite replacement rate,and there is no significant reduction in ultimate load and failure load;the yield ratio of shear wall gradually decreaseas the increase of ceramsite replacement rate,which indicates that the addition of ceramsite increases the safety reserve capacity of shear wall.When the ceramsite replacement rate is 60%,the inelastic displacement of shear wall is maximum.After reaching the failure load,shear wall bearing capacity is not lost,and it has good ductility.