| GRC-PC composite wall panelis a new type of composite wallboard made of composite concrete structure(PC)and glass fiber reinforced cement(GRC).Among them,glass fiber mainly plays a reinforcing role in GRC materials,and it can undergo physical and chemical reactions with cement mortar,thereby enhancing the toughness of the material.Because GRC materials have the advantages of stable performance,simple manufacturing process,and low price,and also have environmental protection,resolvability and other characteristics,which meet the needs of China's current green development,it is widely favored in the assembled building market.At the same time,GRC materials not only have the advantages of high strength,abrasion resistance,fire resistance,water resistance,etc.,but also have strong plasticity,which can be used as the outer layer of the wallboard,making the overall structure have a good artistic texture decoration effect.GRC materials are increasingly used internationally,not only in various construction engineering fields,but also in marine,aerospace,nuclear energy,explosion-proof and other fields.However,certain problems have also been found in the application of GRC materials.For example,cracks in the shrinkage process of wall panels made of GRC materials have also caused some problems in the production of prefabricated buildings.Therefore,cracking caused by shrinkage of GRC-PC wall panels is still an important problem in engineering applications.This thesis is aimed at a new type of GRC one-piece decorative wall panel,which is different from the shrinkage characteristics of previous single materials.In the laboratory,different types of GRC-PC wall panels were poured and studied using static testing strain gauges and other instruments.The connection of PC and GRC boards,the thickness of GRC,and the temperature and humidity of the environment have been used to study the shrinkage properties of PC and GRC boards.The test objects mainly include a single pure GRC wall board,a single pure C30 concrete wall board,and different thicknesses.GRC composite wall panels(15mm,10mm),composite wall panels with different interface connection methods(naked,rough surface connection,steel mesh connection),and different temperature and humidity(indoor and outdoor),relying on the 13 th Five-Year National Key R & D project.The sub-project "Research on New-style Decoration Materials and Composite Thermal Insulation Exterior Wall Panels-Research on Key Technologies of Integrative Production and Installation",after research,the paper achieved the following results:(1)By comparing and monitoring the curve comparison analysis of pure GRC wall panels and pure concrete wall panels with composite panels,it can be seen that the surface strain and internal concrete strain of composite panels are significantly lower than those made of a single material;the crack resistance of composite wall panels The performance is obviously better than that of single-material wallboard.(2)The influence of the interface connection mode on the shrinkage performance of the new GRC-PC composite wall panel.When the interface is connected by a flat joint,the shrinkage strain of GRC materials will be reduced by 72% for outdoor;the shrinkage strain of concrete will be increased by 75%;for indoors,the shrinkage strain of GRC materials will be reduced by 23%;concrete The shrinkage strain is reduced by 19%.When the interfaces are connected by rough surfaces,the shrinkage strain of GRC materials will be reduced by 54% for outdoor,and the shrinkage strain of concrete will be doubled;for indoors,the shrinkage strain of GRC materials will be reduced by 72%;concrete The shrinkage strain is reduced by 22%.By comparing the data of the two types of connection methods,it can be seen that the effect of different connection methods on the shrinkage performance of concrete is greater than that of GRC materials.By comparing the concrete strain data of the two groups of connection methods,it can be known that the use of indoor flat joints at the interface can more effectively improve the shrinkage performance of the composite wall panel than the indoor rough surface connection.(3)The shrinkage test results of the GRC-PC board show that the shrinkage of GRC and concrete under indoor conditions is 23% and 19% smaller than that of the rough surface connection respectively;while the shrinkage ratio of GRC and concrete under rough conditions in indoor conditions is rougher The surface connection is 72% and 22% smaller respectively;the outdoor natural environment can reduce the free shrinkage of GRC material compared to pure GRC by 72% respectively;the shrinkage of concrete becomes 75% larger than the free shrinkage of pure concrete;points The interface is connected by a rough surface.For the natural environment in the outdoor natural environment,the shrinkage of the GRC material will be reduced by 54% compared to the free GRC free shrinkage,and the shrinkage of the concrete will be larger than the free shrinkage strain of pure concrete.Compared with the other three connections,the indoor flat joint can more effectively improve the shrinkage performance of the composite wall panel.(4)From the perspective of the impact of different environments on the shrinkage performance of the new GRC-PC composite wallboard,the shrinkage curve and the shrinkage curve under free shrinkage conditions are closer to each other,and the more difficult it is to crack,the crack resistance is better.The better the performance,by comparing the concrete strain data of the two sets of connection methods,it can be seen that the outdoor conditions are worse than the indoor environment.At this time,although the change in the strain value of the composite board is large,no GRC board cracking has occurred.The sudden and dramatic change in the strain value shows that the GRC-PC composite board used in this experiment can avoid cracking problems in practical engineering applications.(5)By using the "equivalent temperature difference method" in the ABAQUS finite element software,the shrinkage performance of the new GRC-PC composite wall panel is simulated,and then the time-strain curve monitored by the test and the time-strain curve simulated by the finite element analysis can be known : The time-strain curve simulated by the finite element method is basically consistent with the time-strain curve monitored by the test,and the two curves are basically consistent.Figure [52] table [18] reference [69]... |
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