Application Of Fly Ash Concrete In Raft Foundation Of A High-rise Building

In the study of concrete,the performance of fly ash concrete is recognized,mainly using fly ash to improve the performance of concrete mixture,and fly ash is the most important by-product in the power generation production of thermal power plant.Based on the actual project,fly ash is used as a substitute for partial silicon cement,and the mix ratio of fly ash concrete is reoptimized.The purpose is to provide technical support for the application of fly ash concrete in the raft foundation of high building.The raw materials and performance indexes used in the test of fly ash concrete are studied.The fly ash can obviously improve the workability of concrete mixture,the amount of fly ash is increased,the slump loss is reduced,and the hydration heat of concrete is reduced,so that the hydration heat of concrete is reduced.The fly ash concrete is made from the local second grade fly ash in Lanzhou,and the mix ratio of fly ash concrete is designed by orthogonal method.The influence degree of 3 factors,water to glue ratio,fly ash and sand rate,on the compressive strength of concrete in 60 d age is analyzed by the concept of extreme,variance and relative difference of extreme difference in mathematical statistics.The experiment on the performance of fly ash concrete mixture ratio is carried out,and the construction technology in the raft foundation of high rise building is studied,and the effective use of fly ash to solve the problem of fly ash hoarding is provided.The results show that(1)water binder ratio is a significant factor affecting the compressive strength of fly ash,and the compressive strength of concrete decreases with the increase of water glue ratio,and the optimum water binder ratio is 0.43.(2)in the later period of the compressive strength of fly ash concrete,the effect of fly ash content is more significant.With the increase of fly ash content,the compressive strength of concrete gradually decreases,and the optimum content of fly ash is 30%.(3)the sand rate is not a significant factor affecting the compressive strength of the fly ash concrete.In a certain range,the compressive strength of concrete increases first and then decreases with the increase of sand ratio,and the optimum sand rate is 43%.(4)the concrete with water cement ratio of 0.43,fly ash content of 30% and sand ratio of 43% in the construction of raft foundation of high-rise building,the compressive strength,ease,permeability,carbonization resistance and freezing thawing performance of concrete are good,which fully meet the practical needs of the project.(5)in the construction of raft foundation of high-rise buildings,according to the construction technology of raft foundation concrete construction,the quality of fly ash concrete is guaranteed,the total cost of raw materials of fly ash concrete will be reduced.