Study On Preparation And Properties Of Fly Ash Brich From A Coal Gangue Power Plant

Due to the large-scale production of clay bricks,many clay deposits have been on the verge of exhaustion,and land resources are facing a serious threat.Fly Ash is produced by coal-fired power plant.As one of the large amount of industrial solid waste residue,it has become an urgent problem to deal with a large amount of fly ash.The accumulation of fly ash not only takes up a lot of land,but also does harm to soil and environment.With the concept of “Green Building Materials”,the idea of introducing fly ash into the field of building materials has been put forward.Fly Ash brick is a kind of green product which is specially used for recycling waste,environmental protection and energy saving.It is a substitute for traditional clay brick,and has the advantages of being lighter,stronger and cheaper than clay brick,not only in line with the concept of green clay can also reduce the excessive use of resources and reduce production costs and protect the ecological environment.At present,the study of fly ash brick in coal-fired power plant is mostly focused on the study of fly ash brick in coal-fired power plant.This paper is devoted to improving the utilization ratio of coal ash in gangue power plant,starting from exploring the optimum proportion of coal ash brick in gangue power plant,the effects of raw material composition,ratio,preparation technology,water content and water absorption on the strength of fly ash brick and the strength of fly ash brick after freeze-thaw were studied.The aim is to optimize the fly ash brick which is suitable to be popularized in the severe cold area.The results show that:(1)the strength of fly ash specimen increases with the increase of the content of cement,stone powder and water-solid ratio,but a critical value will appear when the content increases to a certain range,and the strength will decrease when the aggregate,water-solid ratio exceeds the critical value,in the way of preparation and maintenance,the strength of pressed fly Ash Specimen is obviously higher than that of vibrated fly ash specimen.The strength increases continuously with the increase of static stop time,but the strength increase is not obvious after the static stop time exceeds 18 hours,there is a critical value in the influence of constant temperature time on fly ash test block.The strength will decrease if the temperature is lower than or higher than 6h.(2)when fly Ash: cement: stone dust = 70% : 20% : 10%,the fly ash brick has the highest flexural and compressive strength.(3)with the increase of fly ash content,water content,water absorption and freeze-thaw times,the strength of fly ash brick will decrease gradually.Through XRD and SEM analysis,it is found that the C-S-H diffraction peak of hydration product of fly ash brick with high strength is abundant,the internal structure is also relatively tight.This study can provide a theoretical basis for popularizing the use of fly ash brick in coal gangue power plant in industrialization and a new direction for finding green and low cost building materials.