Research On Development And Performance Of Recycled Material Permeable Brick

In recent years,with the rapid development of our country’s urbanization process and the construction of a new socialist countryside,a large number of old buildings and structures have been demolished,resulting in a continuous increase in construction waste and solid construction waste.The environment has caused a bad influence.In fact,a lot of construction waste can be properly treated and reused,which not only protects the ecological environment,but also realizes the reuse of construction waste and saves natural resources.At present,how to effectively treat construction waste and make it reusable has become an urgent problem to be solved.On the other hand,a sponge city means that a city can,like a sponge,exhibit good "elasticity" in adapting to environmental changes and responding to natural disasters.The focus of sponge city construction is the construction of urban pavements and roads.Urban pavements and roads should have good water permeability and air permeability,as well as certain mechanical strength and durability.The permeable bricks made of recycled materials in this research meet the construction requirements of sponge cities.Their preparation and application are of great significance for solving environmental pollution problems caused by construction waste,urban waterlogging in rainy seasons,and urban heat island effects.They are of great significance to the future urban development of our country.The improvement of human settlements has a long-term impact.In this study,the waste clay bricks after the demolition of the building were crushed,sieved,washed,air-dried,slurried and other treatment processes were used to obtain recycled brick aggregates,which were used as the main component materials to prepare recycled material permeable bricks.This research focuses on the preparation of recycled brick aggregates,the design of recycled material permeable brick mix proportions,the production of permeable bricks,the preparation and maintenance of permeable bricks,and the mechanical properties,water permeability,and frost resistance of recycled material permeable bricks.Regarding the design of the mix ratio of recycled material permeable bricks,recycled material permeable bricks are composed of permeable concrete with a uniform void structure.This is also the difference between it and other ordinary concretes.The mechanical strength of ordinary concrete is mainly considered when designing the mix ratio.In the mix design of recycled material permeable concrete,both mechanical properties and water permeability need to be considered at the same time.Therefore,this study uses the saturated aggregate volume method for mix design.Regarding the preparation and curing process of recycled material permeable bricks,considering the special porous structure of recycled material permeable bricks that are different from ordinary concrete test blocks,and the aggregates mainly rely on surface cement mortar bonding to transfer force,traditional mechanical vibration methods are adopted.The compaction of the test block will cause the loss of cement mortar along the surface of the aggregate,resulting in sedimentation,which will seriously affect the mechanical properties,water permeability and frost resistance of the permeable brick after molding.The test mixture is put into the mold in batches secondary filler,each layer is manually inserted and compacted to form a compact molding process.The results show that the use of this molding process results in a permeable brick with the surface of the aggregate uniformly wrapped by the cementitious paste and with a metallic luster on the surface;the void ratio between the aggregates of the recycled material permeable brick.The ordinary concrete test block is larger and the cement mortar is less,which leads to the lower early strength of the permeable brick.The maintenance and demoulding method of the ordinary concrete test block will cause the aggregate of the permeable brick corners to fall off or the integrity.For loose damage,this test adopts the method of permeable bricks after being compacted and molded,and sent to the standard curing room together with the mold for curing until 48 h demoulding,and after demolding,they are sent to the standard curing room for curing to 28 d age.In terms of mechanical performance test and water permeability of recycled material permeable bricks,the controlled variable method is used to test the compressive strength and flexural strength of recycled material permeable brick test blocks with different water binder ratio,target porosity,sand brick bone rate,and recycled brick aggregate content.Strength and water permeability test,analyze the influence of various influencing factors on compressive strength,flexural strength,and water permeability,and the optimal mix ratio range that takes the balance of mechanical properties and water permeability into account: water binder ratio is0.3～0.32,target porosity is 22% ～24%,sand brick bone rate is 30%～35%,the content of recycled brick aggregate is 1104.9 kg/m~3.Regarding the frost resistance of recycled material permeable bricks,the same mixing ratio test block as the mechanics and water permeability test was used to test the frost resistance.The quick freezing method was used to test the mass loss of different mixing ratio test blocks under different freeze-thaw cycles,so as to measure the freeze-thaw damage of permeable bricks,the optimal mix ratio range in terms of frost resistance:water binder ratio is 0.34,target porosity is20%～22%,sand brick bone rate is 35%,the content of recycled brick aggregate is 1074.9kg/m~3.