Effect Of Vitrified Microsphere And Pore Type On Physical Properties Of Ceramsite Concrete Hollow Block

Using vitrified beads and ceramsite instead of coarse and fine aggregates to make light hollow blocks can effectively save resources and energy,reduce the density of hollow blocks,reduce self-weight,and improve the wall thermal insulation performance.A large number of preliminary tests show that water-binder ratio,air content,glass bead content,fine aggregate content,ceramsite pretreatment method and ceramsite content are the key factors affecting the thermal conductivity of concrete,and the glass bead content can significantly affect the physical properties of hollow blocks.Therefore,this paper first studies the influence of water cement ratio,air content,glass bead content,fine aggregate content,ceramsite pretreatment method and ceramsite content on thermal conductivity of ceramsite concrete,and determines the basic mix ratio of ceramsite concrete with smaller thermal conductivity.On this basis,different amount of glass beads are added to study the effect of glass bead on the physical properties of hollow block,and determine the glass-filled block.Finally,ANSYS software is used to simulate and analyze the thermal performance of hollow block,and then optimize the performance of concrete to prepare a kind of lightweight aggregate concrete hollow block which can improve the effect of heat preservation and energy saving.Firstly,the effects of water-binder ratio,air content,vitrified microsphere content,fine aggregate content,ceramsite pretreatment method and ceramsite content on thermal conductivity of concrete are studied.Through the preparation of concrete thermal conductivity board,the macro performance test method was used to test the thermal conductivity of concrete by water-binder ratio,air content,vitrified beads content,fine aggregate content,ceramsite pretreatment method and ceramsite content.The results show that the thermal conductivity of concrete is inversely proportional to water-binder ratio,air content,vitrified beads content and ceramsite content.With the increase of sand content,the thermal conductivity of concrete first increases and then decreases,showing a non-linear relationship.The thermal conductivity of concrete made of ceramsite after 24 hours of pre-wetting is the smallest.Secondly,the effect of glass beads on the physical properties of hollow block is studied.By changing the content of glass beads in concrete,the appearance quality,size,bulk density,moisture content,water absorption,relative moisture content,drying shrinkage,softening coefficient,frost resistance and compressive strength of the hollow block were tested.The results show that with the increase of vitrified beads content,the water content,water absorption,relative water content and drying shrinkage of hollow block increase gradually,the density and softening coefficient of block decrease gradually,the frost resistance decreases gradually,and the compressive strength decreases continuously.With the increase of curing time,the 7d compressive strength of hollow block can reach 75%of 28d compressive strength.%-85%,which indicates that the compressive strength increases rapidly in the early stage and slowly in the later stage.Finally,based on the optimum proportion of hollow block in the previous test,the theoretical calculation of heat transfer coefficient K and thermal inertia index D of hollow block is carried out.Three kinds of hollow block masonry walls are simulated by using ANSYS simulation software under the condition of steady-state thermal analysis.At the same time,a comparative analysis is made on the two kinds of horizontal gray joints of hollow blocks which are not covering the whole surface of hollow blocks and covering the whole surface of hollow blocks.The results show that the heat transfer coefficient K of masonry wall is 0.97 and the thermal inertia index D is 3.02,which all meet the requirements of the code.When the hollow block is of the same size and the same base material,the thermal insulation performance of the hollow block with three rows of holes is better than that of the hollow block with one row of holes;when the air separation ribs in the hollow block are different,the calcium silicate plate with small thermal conductivity is used as the separation rib,and the thermal insulation performance of the hollow block is better.If the hollow block wall constructed with ordinary mixed mortar is not covered by the whole hollow block surface,its heat transfer coefficient can be reduced by 2%compared with that covered by the whole hollow block surface.