Study On The Characteristics Of Circulating Fluidized Bed Ash Used As Stiff Concrete Admixture

Circulating Fluidized Bed Coal Combustion is a highly efficient non-polluting combustion technology.the Circulating fluidized bed ashes(CFB ashes)is CFB boiler discharged.because of its high sulfur content,high water demand and hydration swelling characteristics,so it can not effectively large-scale use.Most of our country is currently open dumps,occupation of land resources,and even affect the further promotion of Circulating Fluidized Bed Coal Combustion Technology.Stiff concrete differs from normal concrete,the low water,low W/C and is in stiff state molding process.Because of these undesirable characteristics the ordinary cement concrete can not be efficiently utilized for CFB ashes,but the stiff concrete may reduce or weaken CFB ashes some undesirable characteristics,and CFB ashes activity can fulfill use in low-level stiff concrete.In this paper,relying on the project to complete the construction of Chuanxing Village rural road,and by the project to study the CFB ashes Unlike other admixture in practical use.This paper selects five CFB ashes to study,use the cementitious experiment,glue sand experiment and concrete experiments to test CFB ash admixture characteristics.Studies shown that:(1)effects of different dosage of CFB ashes on mortar properties,experimental study of the content from 10% to 50%,according to the result CFB ashes mixing amount 10% to 30% more reasonable dosage range.(2)by changing the grinding fineness of the CFB ashes,select surface area is 5120cm~2/g?6385cm~2/g?7934cm~2/g?8893cm~2/g,the four different fineness of CFB ashes,the analysis results obtained the finer the CFB ash can improve the early strength of cement mortars,but the high fineness of the late strength contribution is not obvious.(3)According to the Chongqing Municipal CFB ashes piled actual situation,comparative study of the differences between wet ashes and dry ashes,wet ashes found in the active substance has been largely water-reactive,to the late strength mortar contribution obvious,the need to use and dry ash treated differently.(4)CFB ashes hydration expansion characteristics can compensate for shrinkage based cementitious materials.(5)Based on the results of glue sand experiment,different content CFB ashes on stiff concrete performance analysis,optimal dosage draw a CFB ashes is about 20% to 30%.(6)The polycarboxylic series of water reducer and CFB ashes are compatibility,and performance in common use in stiff concrete can be a good improvement of stiffconcrete.By study the CFB ashes admixture for use in stiff concrete,for the completion of the demonstration project road laid the technical foundation.And by comparison with ordinary cement concrete,including the cost of construction,analysis of the CFB ashes is used in stiff concrete pavement,not only the use of a large amount of industrial solid waste,and also the economy is better than ordinary cement concrete.Providing technical reference for the future large-scale resource use CFB ashes.