Study On Weatherability Of Sandwich Insulation Wallboard From WSPC System

With the rapid development of the the construction industry and the improvement of energy-saving requirements,exterior wall thermal insulation system has been widely used in practical engineering.Also,the durability has become the important factor affecting the service life and the effect of energy saving of the wall.The sandwich thermal insulation wallboard developed by Hebei Academy of building research for the special shaped column frame system(WSPC)was studied.In this paper,the weather resistance of the wall was studied by the combination of test and software simulation.The main contents are as follows:1.Experimental study on weather resistance of sandwich insulation panel with WSPC system:the temperature and stress of each functional layer of the wall was monitored and analyzed,and the wall appearance was checked and recorded to study the weather resistance and stress deformation characteristics of the wallboard.The experimental results show that obvious leakage cracks,pulverization,hollowing,spalling and other changes were not appeared in the test process,and no tile loss and damage situation.It shows that it can be tested by weather resistance test and the weather resistance is good.The strain variation of wallboard under different positions and cycles was studied,which shows that due to the pull and tie effect of truss steel bars and the influence of peripheral confinement,the concrete on the exterior wall is blocked in normal thermal expansion and cold contraction,so the "thermal expansion" is blocked to produce compression stress and the tensile stress is produced when "cold contraction" occurs.2.Study on deterioration law of adhesive strength of decorative wall of WSPC sandwich insulation wall in weathering test:The tensile bond strength was tested during different stages in the experimental process to analyze the deterioration law.The test results show that after the test the bond strength between concrete and brick wall with an average of 0.86 Mpa,the adhesive strength of the decorative brick decreases by 8.1% after the hot rain cycle,and decreases by 5.1% after the thermal cooling cycle,and decreases by 12.1%after the freeze-thaw cycle,with the disconnection is mainly based on concrete.So the bond strength reduction is not very large.In comparison,the freeze-thaw cycle has the greatest impact,followed by the thermal rain cycle,the smallest is the hot and cold circulation.The main reason is that the temperature and moisture stress caused by water entry and thefreeze-thaw cycle between the interfaces lead to a certain bond strength loss.3.Simulation of temperature effect under the condition of weather resistance test and actual environment were done by the finite element analysis software ABAQUS.The results show that the constraint of the truss steel and bolt have obvious restraint effect on its deformation,which shows that the free expansion at high temperature is blocked and the contraction in the low temperature stage is in tension state.And the stress and deformation of concrete are mutually inhibited.There is a great risk of cracking in the middle of the wall and around the entrance and lower part.Research shows that the numerical simulation of the nonlinear surface temperature effect using the finite element method is put forward to evaluate the reliability of results,according to the analysis for the typical building exterior wall insulation and wall temperature effect simulation and deterioration.4.Temperature field and temperature stress model under the influence of external environment and solar radiation in different seasons in Shijiazhuang were established by the finite element analysis software ABAQUS.The influencing factors of wall temperature field and the distribution law of wall temperature stress were analyzed.The results show that the temperature distribution of wallboard is influenced notablely by solar radiation.The wall deformation in summer is more obvious than winter,and the possibility of cracking is greater.The research provides a basis for the optimization of WSPC system of the new type sandwich wall insulation.