Preparation Of Non-fired Fly Ash Ceramsite And Research On Ceramsite Lightweight Aggregate Concrete

China is a big country of coal-fired power generation.Fly ash is industrial solid waste produced by coal-fired power plants.At present,China's fly ash emission ranks first in the world.This paper uses ? grade active fly ash as raw material to realize the conversion from fly ash to non-burning coal ash ceramsite and then to ceramsite lightweight aggregate concrete.The main work of this paper and the research results obtained are as follows.1.The activation effect of four basic activators,such as Na2CO3,Ca(OH)2,CaO and Na(OH),on the activity of ? grade fly ash was studied for the preparation of no-burn pulverized coal ash ceramsite.The results show that CaO can stimulate the activity of ?grade fly ash best.2.In this paper,using ? grade fly ash as raw material,with P.52.5 cement,quicklime,sodium silicate,desulfurization gypsum as admixtures,using steam curing to prepare non-burning coal ash ceramsite.Taking cylinder compressive strength,1h water absorption and bulk density as evaluation indexes of ceramsite properties,the main effects of admixtures on the properties of ceramsite were studied by single variable test.Orthogonal test was set to explore the interaction between admixtures and the influence degree of each factor on the properties of ceramsite,and mineral analysis and scanning electron microscopy were used to explain the mechanism of ceramsite strength.Combined with single variable and orthogonal test,the optimum ratio of new type of non-sintered coal ash ceramsite was given.The results show that the ceramsite meets the 900 grade artificial lightweight aggregate standard required by the national standard GB/T 17431.1-2010 for lightweight aggregate and its test method.3.Based on the summary of experience,this paper optimized the preparation process of non-burning type powdery coal ash ceramsite,and proposed new adding process of quick lime,adding process of water,nucleating process and curing process;The preparation process route of non-burning type powdered coal ash ceramsite was put forward,including quicklime pulping,wet material preparation,pelletization and platepelletization,sifting,natural curing,moisture curing and steam curing.This process has the advantages of high utilization rate of raw material,high initial strength of raw material ball,small crushing rate,high compressive strength of ceramsite cylinder,lower cost compared with the traditional sintering of coal ash ceramsite,and has a broad development prospect.4.In this paper,the lightweight aggregate concrete is prepared by using the self-made powdered coal ash ceramsite as coarse aggregate,and basalt fiber is used to improve the working performance of ceramsite concrete and enhance the mechanical properties of ceramsite concrete.The results show that the basalt fiber reinforced ceramsite concrete meets the LC45 grade lightweight aggregate concrete application technical standard required by JGJ/T 12-2019.