Preparation And Properties Of Whole Coal Gangue Unsintered Permeable Brick

Shanxi is the largest coal province in China,such kind of coal resources help China step into high speed growth of development,at the same time,solid waste,coal gangue was been produced.At present,the utilization rate of coal gangue in Shanxi and even the whole country is relatively low,and most of them are treated by landfill.Therefore,the comprehensive utilization of coal gangue and improving the utilization rate of coal gangue become urgent problems to be solved.In recent years,the country has paid increasing attention to the environment we live in and has strengthened the protection and governance of the environment.A water-permeable material,permeable brick,contributes to establish an environmentally society.Firstly,inside of the permeable brick has abundant pores,which help rain and snow water quickly penetrate the ground,reduce the flood discharge pressure and avoid the phenomenon of“watching the sea in the rain”,when paved on the road surface.Secondly,the pores also provide sound absorption effects,which can reduce noise in the city sound pollution.Thirdly,the water permeability of the permeable bricks is also conducive to replenishing and conserving groundwater sources.In short,there is a positive effect on our environment using the permeable bricks.This subject mainly studies the preparation of permeable bricks by using coal gangue in the absence of sintering.Combined with the structural characteristics and purposes,the preparation process of permeable bricks is studied,the design method of mixture ratio is discussed,and various factors are analyzed.According to the influence of brick performance,the preparation method of improving the splitting tensile strength was obtained,and the prepared permeable bricks were studied for frost resistance and self-cleaning.The specific experimental research results are as follows:(1)The advantages and disadvantages of the mass method,the specific surface area method and the volume method in the mixture design method were compared and analyzed.The design method of the mixture ratio suitable for the experimental study in this paper which was determined by the volume method.(2)The effects of forming and curing methods on the performance of permeable bricks during the preparation of permeable bricks were studied.The optimum molding pressure was 4MPa and the holding time was 45s.The standard curing and autoclave curing were compared and analyzed.The effects of pre-feeding period,autoclave temperature and autoclave time on the strength of permeable bricks in autoclaved curing were studied.The pre-feeding period was 10h and the autoclaved temperature was 183°C.When the autoclave time is6h,the strength of the permeable brick is higher.(3)The effects of water-cement ratio,porosity,and aggregate size of coal gangue on the strength and permeability coefficient of permeable bricks were studied.The strength and permeability coefficient of permeable bricks were obtained when the water-cement ratio was 0.28 and the porosity was 18%.Preferably,as the particle size of the gangue aggregate becomes larger,the strength of the permeable brick becomes lower,and the water permeability coefficient becomes larger.The permeable coefficient of the permeable brick prepared under the preferred preparation conditions and the preferred water-cement ratio,porosity,and suitable aggregate particle size can meet the standard A-level standard,but the strength is low.In this test,two methods were adopted to improve the strength of the permeable bricks.One is to grade the aggregate and the other is to add the external admixture.When the aggregate gradation is 1.18--3.36mm(10%),2.36--4.75mm(36%),4.75--9.5mm(54%),and the content of the externally mixed fly ash is 15%,the permeable brick The splitting tensile strength is 3.75MPa and the water permeability coefficient is1.71×10~-22 cm/s.(4)The anti-freeze performance of permeable bricks was studied.The anti-freezing mechanism was analyzed.The variation of splitting tensile strength,quality and permeability coefficient of permeable bricks before and after freezing and thawing were analyzed.The porosity and permeability of permeable bricks and the effect of water content in the pores on freeze-thaw damage were explored.(5)The self-cleaning function of permeable bricks was studied.The effects of illumination time,amount of spray agent and clogging degree of permeable bricks on the self-cleaning ability of permeable bricks were studied.The three factors were analyzed by orthogonal test.The influence of performance recovery in order is that the amount of spray agent>the degree of blockage>the time of illumination.