Development Of Inorganic Cementitious Material And Its Application In Bamboo Structure

Bamboo structure has a long history and has unique advantages in green,low carbon and sustainable aspects.Bamboo is a sustainable and environmentally friendly renewable building material with fast growth rate of 3 to 5 years.However,in the field of engineering bamboo adhesives,the main organic adhesives used at present are urea-formaldehyde,phenolic resin and so on.The bond between organic adhesive and bamboo is good,but in the process of production and use,it will cause environmental pollution,and the fire resistance and durability are poor.This thesis conducted the research of magnesium oxysulfate(MOS)inorganic cementitious material,inorganic glue bamboo,inorganic glue composite bamboo,bending resistance test and fire resistance test of bamboo beam members.The feasibility of using inorganic cementitious for bamboo construction is preliminarily verified.Firstly,MOS inorganic cementitious materials with excellent mechanical properties,water resistance,shrinkage and drying properties and microscopic properties can be prepared by suitable modification technology.Secondly,MOS inorganic cementitious material was used as adhesive to prepare inorganic laminated bamboo and inorganic composite bamboo.A suitable MOS inorganic cementitious material can be used to prepare laminated bamboo with high bond shear strength and bending strength.When the laminated bamboo is bent and destroyed,the crack extends along the rubber layer to the bamboo matrix,which can realize the ideal failure form of the rubber layer and the bamboo material broken.Different mix design of inorganic cementitious material,pretreatment method of bamboo bundle,forming technology of composite bamboo material,curing condition of composite bamboo will affect the mechanical properties,combustion properties and failure morphology of composite bamboo,but the adhesion and cooperative work between bamboo and inorganic cementitious material are good.Finally,based on the probability model of normal distribution,the design values of compressive strength and tensile strength of composite bamboo beams are calculated,and the feasibility of composite bamboo beams as structural members is preliminarily explored.In the initial stage of static load test,the composite bamboo beams are basically in elastic state,the mid-span deflection increases with the increase of load,with the increase of load,the bamboo bars on both sides of the beam bottom are broken,the fracture part extends to the middle,and there is no characteristic of peeling and cracking along the rubber layer.When the failure occurs,the mid-span deflection of the beam is large and the failure form is ideal ductile failure;Under the action of fire,inorganic glue will release water,and the released water will help to reduce the overall heating rate of composite bamboo,improve the fire resistance of composite bamboo,the farther the temperature is from the upper and lower edge of composite bamboo beam,the higher the bearing capacity and good ductility of MOS inorganic cementitious composite bamboo beam.