Seismic Performance Test And Calculation Theory For Recycled Aggregate Thermal Insulation Concrete (RATIC) Shear Wall

With the improving of national requirements for building energyefficiency, green building gradually become focus of social concern anddeveloping trend in future. For deriving a variety of advantages in the whole lifecycle, it has become the hot topic of green building material research that theself-heat insulation system representing by thermal insulation concrete structure.Due to the rapid development of construction business increased the demand forbuilding materials, the consumption of resource and the damage to environment,the recycling of increasing construction waste has become the key issue ofmodern construction which urgent to be solved, recycling recycled aggregatesfrom construction waste has begun to spread abroad and promote in China.Especially the recycled aggregate thermal insulation concrete (RATIC) whichhaving the characteristics of green concrete makes the best use of recycledcoarse aggregate and has good insulation performance, the thermal conductivitycoefficient can fall below0.35W/(m K).it is the development trend of newconcrete material in China for next decade. There were many related research on the structure mechanics characteristic and seismic capacity about recycledconcrete or light aggregate concrete with the characteristics of insulation andbearing, but the research on seismic performance of RATIC structure is a blank.By using recycled coarse aggregate instead of natural aggregate and mixing withlight aggregate for thermal insulation performance in RATIC, the research onbearing and seismic safety of RATIC is particularly critical. This paper includesthe following content.(1)The distribution rule of compressive strength and the whole stress-straincurve had been studied by using hydraulic servo testing machine in this paper,the data of stress and strain was acquired by static resistance strain gauge.Results show that the cube compressive strength of RATIC accords with normaldistribution. The influence of recycled coarse aggregate to cube compressivestrength distribution of RATIC is far greater than that of glazed hollow bead.The cube compressive strength of RATIC in this study is35MPa and elasticmodulus is2.13×104N/mm4.(2)The microstructure and crack distribution of RATIC under loads at thedifferent level were observed by using scanning electron microscopy (SEM), theformation process and influence factor of micro cracks were used to explainmicro performance of RATIC. Results show that due to the recycled aggregateswere crushed by huge rolling force, the invisible damages were hidden ininternal and interface recycled aggregate and they become the weakest areas ofthe whole RATIC system. The number and size of the hole in interfacial area were greatly reduced by adding nano-scale and micro-scale admixture, theinterfacial zone of glazed hollow bead is not the most vulnerable area of RATIC.(3)The good bonding performance is necessary to ensure RATIC can worktogether with reinforcement. In this paper,36specimens were analyzedthroughpull-out test, Results show that due to low elastic modulus of RATIC, thegripping force between reinforcement and RATIC in the early stage is slightlylower than that of normal concrete. The bonding strength between deformedreinforcement and RATIC was slightly larger than that of normal concrete, thepeak slippage was small, its bond strength are greatly influenced by the strengthof cement slurry; When the diameter of deformed reinforcement is too larger, theinternal fracture along the aggregate was appeared in the fracture surface ofRATIC.(4)In this paper, the pseudo-static test of ten shear wall specimens withdifferent parameters have been conducted, the parameter variables include:concrete material, shear-span ratio, axial compression ratio and reinforcementratio, this paper studied the effects of every design parameters on the seismicperformance of RATIC shear wall under low cyclic loading. Results show thatthe load bearing capacities of GSW in every phase are slightly increasing andthe peak displacement is also significantly higher than that of SW.The ductilityperformance of GSW improves along with the increase of its shear span ratio.With the increase of axial compression ratio, the bearing capacity increasesslowly gradually while the loss of ductility is greater. With the increase the reinforcement ratio of concealed column, the main pressure stress in the pressurezone of GSW increases more obviously. Under the same load, the RATIC havelarger plastic deformation ability and the internal reinforcement stress is moreeven.(5)The nonlinear analysis was completed by using the ANSYS finiteelement software, the analysis results are in good agreement with test results,and it provides an effective method for the analysis of RATIC shear walls withextended parameters.(6)Combining with mechanics analysis theory on shear wall at home andabroad, this paper has summarized the quantitative calculation and evaluationmethods about bearing capacity and displacement of RATIC shear wall on thebasis of test results. The deformation ability of RATIC shear wall structure is thekey characteristic and it should be concerned in nonlinear phase. This paperhave analyzed the calculation methods about the sectional curvature, sectionaldisplacement angle and horizontal displacement of RATIC shear wall in eachstage, the formulas for calculating have been checked and adjusted. This paperputs forward to the restoring force curve model of RATIC shear wall with highshear span ratio which depends on bending deformation, and provides partialcalculation formula on the elastic-plastic displacement and bending-sheardisplacement of shear walls, the calculated results are in good agreement withthe test results.