Study On The System Of Cast In Place External Thermal Insulation Wall With Rib Lath Stay-in-Place Mould

Formed particles concrete is made from polystyrene foaming particles,cement,water and foaming agent as the main component,inorganic and organic composite materials prepared by a certain ratio.It has many advantages,such as Seamless whole cast,thermal insulation,sound insulation,fire protection,anti cracking,anti freeze durability.The fomed particles concrete is widely used in the field of roof insulation,and has achieved good economic and social benefits.In order to widen the application field of the new material with independent intellectual property rights,in this paper,the external thermal insulation wall cast in place with rib lath stay-in-place mould was presented.The heat insulation wall is fixed on the outer surface of the outer wall with a rib lath as a saty-in-place mould,formed particles concrete as a heat insulation material is poured into the saty-in-place mould,one time casting,the whole forming.So far the study on the physical and mechanical properties of the formed particles concrete and bonding properties,the casting and the lateral pressure of stay-in-place mould system,etc.are few relevant results appear,so this paper carried out relevant research in these areas.The main research contents and conclusions include the following aspects:(1)The physical and mechanical properties of the foamed particles concrete were studied,and the optimum mix proportion was determined.The orthogonal experiments plan of four factors and five levels has been designed.In this plan,the flow value,cube strength and thermal conductivity of foamed particles concrete are used as evaluating indicators,the substitution of fly ash,content of polystyrene particles,water cement ratio and degree of wet density are used as influence factors.The Experimental research on physical and mechanical properties of formed particles concrete is carried out systematically.Without considering the interaction of the various factors,the relationship of each influencing factor on each evaluating indicator is obtained.According to the above,a more reasonable mix proportion of foamed particles concrete is obtained.(2)Two section constitutive equations were proposed for the application of foamed particles concrete materials.The complete stress-strain curve of the formed particles concretewith different mixing ratios were obtained by experiments.The failure mechanism of the foamed particles concrete,and the influence of loading rate,content of polystyrene particles and wet density on the complete stress-strain curve of formed particles concrete were researched and analyzed.According to the complete stress-strain curve,the conclusion is drawn that the formed particles concrete has the typical elastic-plastic characteristics.Based on this,a two segment phenomenological constitutive equation was proposed,which was based on the content of polystyrene particles and the grade of wet density as the influencing factors.The stress-strain curves of the formed particle concrete were well consistent with the experimental results.(3)The bonding performance between the foam concrete and the wall material was studied.Three kinds of main wall materials,such as concrete,cement mortar and ceramic hollow block,were selected as matrix material.The experimental research on the bonding properties of bonding surface between the matrix material and the formed particles concrete with three kinds of wet density(250kg/m3,300kg/m3,350kg/m3)were carried out.Two types of shear failure and two types of tensile failure of bonding surface were obtained.The influence of matrix structure layer material type and the wet density grade on the shear properties and tensile properties of bonding surface were studied.And the conclusion has been obtained that the adhesive bonding performance between the formed particles concrete and concrete and mortar is excellent.The formed particles concrete can be directly bonded with concrete and mortar,no need to add a daub binder between the formed particle concrete and the matrix structure layer.(4)The experimental study on the lateral pressure of the foamed particles concrete in the stay-in-place mould system of the rib lath was carried out.Two different types of rib lath stay-in-place mould system with different connection types were designed.The experimental measured value of lateral pressure of rib lath stay-in-place mould system,the maximum deformation value and the maximum deformation position have been obtained respectively,which have two type of connections.The construction method of rib lath stay-in-place mould was introduced,and the problems of slurry leakage and deformation during casting process are discussed and researched.And finally come to the conclusion that this construction method is feasible.(5)According to the measured values of the lateral pressure test and the water pressure formula,a formula for calculating the lateral pressure of the external thermal insulation wall of stay-in-place mould is presented.According to this formula,using the finite element analysis software ANSYS,the mechanical response in the lateral pressure of the stay-in-place moud system of rib lath has been studied.The results show that this formula can be used to predict the lateral pressure of the stay-in-place mould system of the rib lath.