Study On Proportion Optimization And Compression Law Simulation Of Pulverized Coal Ash Ceramsite Concrete

As a coal resource-based province,Shanxi Province is in the critical period of resource transformation and development.It is of great significance to carry out the sustainable development strategy and develop the comprehensive utilization of solid waste in Shanxi Province.Combined with the current situation of power industry in Shanxi Province,which is dominated by thermal power and has a large amount of fly ash as a by-product,the problems of excess capacity of fly ash in Shanxi Province and environmental pollution caused by landfill treatment are solved.Promoting the recovery and utilization of fly ash plays an important role in promoting the economy of Shanxi Province.Pulverized coal ash ceramsite is a light aggregate sintered from fly ash.Taking it as aggregate instead of stone in concrete can effectively solve the problem of comprehensive utilization of Shanxi Province electric power development.Although light aggregate appeared earlier and the utilization rate was higher in some cities,there are still some problems in its large-scale application in the field of architecture.For example,the density of light aggregate is much lower than that of stone or even water,which leads to the phenomenon of buoyancy of light aggregate in the process of mixing molding;The characteristics of porous inside lightweight aggregate make the mixing mode and the properties of interfacial transition zone of lightweight aggregate concrete different.The lower strength of the light aggregate and the regular shape also change the stress distribution of the concrete during compression.Based on the above problems,this thesis first of all to light aggregate porous change were analyzed to explore the way of mixing,through the literature research the multiple mixing methods influence on strength of fly ash lightweight aggregate concrete,and puts forward a new type of mixing method,based on the obtained light aggregate through CT scan of space than configuration;Secondly,on the basis of comprehensive test,the importance coefficient of cement and sand ratio to the compressive strength of lightweight aggregate concrete was obtained through correlation analysis,and the optimal mixture ratio of lightweight aggregate concrete with fly ash was obtained under fixed water-cement ratio.Finally,numerical simulation is carried out by particle flow simulation software PFC to obtain the stress distribution and failure mode of light aggregate concrete under different conditions,which provides theoretical guidance for subsequent advancement.The main work of this paper is divided into the following three aspects.(1)Based on the mesoscopic study of lightweight aggregate concrete and the strength law of the interface transition zone,a new mixing method,the pre-wet mixing method,is proposed.Compared with the traditional mixing method of light aggregate concrete,the strength,work-ability,dry apparent density and other factors of light aggregate concrete under different mixing schemes were obtained through experiments.By analyzing the above test data,the behavior changes rule of concrete interface transition zone caused by aggregate porosity is obtained,and a kind of mixing technology of fly ash light aggregate concrete is obtained.(2)Based on the research content mentioned above,the compressive strength of lightweight aggregate concrete with different sand ratio and cement dosage was obtained through comprehensive tests.On the basis of the test data,the importance coefficients were obtained through the grey correlation analysis method.By analyzing the change trend of the importance coefficients,the influence rule of the cement and sand content change on the strength of the pulverized coal ash ceramsite concrete at different ages was obtained.Based on this law,the mixture ratio of pulverized coal ash ceramsite concrete is optimized,and the optimal mixture ratio of fixed water-cement ratio of light aggregate concrete is obtained by adding fly ash and ore powder.(3)Based on the particle size of the aggregate profile of the ceramsite concrete section scanned by CT,the paper obtained its distribution law.Through particle flow numerical simulation analysis,the stress and strain curve of the pulverized coal ash ceramsite concrete was obtained.By comparing the changes of the curve and the specific situation of the corresponding model,the law of stress development and crack development in the process of pulverized coal ash ceramsite concrete is analyzed completely.Through the compression of different volume ratio and different particle size of pulverized coal ash ceramsite concrete model,the change rule of strength of pulverized coal ash ceramsite concrete under different conditions is explored,which provides guidance for industrial production of ceramsite and building use.