Experimental Study On Bending Resistance Of Modified GLC Siliceous Lightweight Wallboard

With the development of building industrialization in our country,the development and application of prefabricated buildings gradually become mature,various innovative researches on prefabricated buildings emerge in an endless stream.The prefabricated wallboards are also a major research hotspot,especially the composite wallboards synthesized by traditional walls and new materials become a major development trend.The modified GLC silicon lightweight wallboard studied in this paper is a new type of composite wallboard that replaces the alkaliresistant glass fiber net in the ordinary GLC silicon lightweight wallboard with the steel wire net or changes the construction mode.It has the characteristics of high initial stiffness and good crack resistance.The composite wallboard will produce initial cracks due to the force in the process of transportation turbulence and lifting,and will be affected by bending due to external forces such as wind load in the use of high-rise buildings.Therefore,it has important significance to provide theoretical basis for the study of the flexural performance of modified GLC silicon lightweight wallboard in actual engineering.14 pieces of siliceous lightweight wallboard specimens are designed in this thesis,which are used to be studied on the flexural performance.The 14 pieces of silicon lightweight wallboard are divided into 7 groups,also each group has the same parameters and experimental method.Thereinto,five groups are modified GLC silicon lightweight wallboard,two groups are common silicon lightweight wallboard as controlled trials.By analyzing the failure modes,the crack development of composite wallboard with different reinforcement materials,different composite methods,the distance between reinforcement materials and the axis under uniform load,also according to the test results,the cracking capacity and ultimate bearing capacity of composite wallboards with different reinforcement materials and different composite methods are analyzed.The flexural cracking bearing capacity formula and ultimate bearing capacity formula of modified GLC silicon lightweight wallboard are given.The experimental results show:（1）Under the uniform distributed load,the failure mode of modified GLC silicon lightweight wallboard and ordinary GLC single-layer core silicon lightweight wallboard is bending failure.The development of cracks is basically the same,which indicates that steel wire mesh instead of alkali-resistant glass fiber mesh has similar flexural resistance.（2）After replacing alkali-resistant glass fiber mesh with steel wire mesh,the cracking load of composite wallboard is significantly improved,which indicates that the replacement of reinforcement material enhances the initial stiffness of specimen and can effectively inhibit the development of cracks.（3）Through the comparison between different ways of composite specimens,it shows that under the circumstance of same reinforced material,multi-layer composite wallboard has more obvious increase of cracking load than single layer composite wallboard,especially when multilayer core material of modified GLC silicon lightweight wallboard rises more apparently.In order to illustrate the application of multi-layer composite way changed the form of the cross section of composite wallboard,which makes the moment of inertia of the composite wallboard increase.Thus,the cracking load is increased.（4）Through the comparison of the specimens with different distances between the reinforcing material and the axis,it is found that under the circumstance of the same reinforcing material and composite mode,only changing the distance between the reinforcing material and the axis has no obvious influence on the stiffness and cracking capacity.（5）By comparing the ultimate bearing capacity of each specimen,it is found that the effect of modified GLC silicon lightweight wallboard on improving ultimate bearing capacity is not obvious under the same composite mode,which indicates that there is almost no difference between the ultimate tension provided by steel wire mesh or alkali-resistant glass fiber mesh,which has a significant effect on improving the cracking capacity.（6）Through the comparison of specimens with different composite modes,it is found that the ultimate load of multilayer composite wallboard is not significantly increased compared with that of single-layer composite wallboard under the circumstance of the same reinforcement material,whicih indicates that the composite wallboard mainly relies on the outermost material to provide tensile force when it fails,while the reinforcement material of the inner layer provides less tensile force.（7）The failure mode of the specimen is mainly bending failure.In the early stage of loading,cracks are not developed,and the specimen is in the elastic stage.At this time,the combination of mortar and foamed cement core material is good,and the two parts can work well together.With the increasing of load,transverse cracks appear in the middle tensile zone of the bottom span first.At this time,the specimen enters the elastic-plastic stage,and the mid-span deflection changes more and more obviously.When the specimen finally destroyed,the cracks in the bottom and side of the wallboard were mainly distributed in the range of 1/4～3/4,and the cracks were mainly under bending tension.（8）According to the theoretical analysis and test results,the calculation formula of flexural capacity and ultimate flexural capacity of modified GLC silicon lightweight wallboard are given.The theoretical results are in good agreement with the experimental results,which provides theoretical basis for the design of modified GLC silicon lightweight wallboard.（9）From the analysis of the overall flexural performance,the modified GLC silicon lightweight wallboard is superior to the ordinary GLC silicon lightweight wallboard.Therefore,the application of the modified GLC silicon lightweighth wallboard in practical engineering applications can obtain better results.