Optimization Of C50 Mechanism Sand Self Compacting Concrete's Mixture Ratio In Jian En Highway Project

With the increasingly large-scale,complex and high-rise building of concrete engineering,self compacting concrete has been widely applied for its excellent performance.At the same time,with the rapid development of China's infrastructure and more attention to environmental protection,the replacement of natural sand by mechanism sand has become a trend in the concrete industry.Whether the self compacting concrete made of mechanism sand can meet both the workability and the required strength is also needed for further research.In view of the lack of natural sand resources in Enshi area,this paper first studies the situation of mechanism sand and other raw materials of concrete.Then,taking the C50 mechanism sand self compacting concrete as the research object,the paper studied the self compacting concrete working with the volume ratio of plasma bone,water glue ratio,fly ash content,sand rate and stone powder content in the mix proportion design.The effects of sexual and mechanical properties.The main results are as follows:(1)in a certain range,the ratio of water to glue and the increase of fly ash content will help to improve the working performance of the mechanism sand self compacting concrete,but it is not good for the mechanical properties of the concrete.The pulp volume ratio has a little influence on its workability and compressive strength in the range of 0.48~0.58.When the sand rate is 0.5,the working performance and compressive strength of the machine-made sand self compacting concrete are all the best.(2)when the content of stone powder is not more than 7%,the slump,extensibility and compressive strength are not significant.When the stone powder content reaches 12%and 17%,the slump phase decreases 12.5% and 22.9% when the slump phase is 7%,and the extension degree decreases by 20.3% and 27.8%,and the 28 d compression strength decreases 14.4% and 16.6% respectively.The 7d and 28 d compressive strength of self compacting concrete can be increased by appropriate stone powder instead of fly ash,especially the early compressive strength.When the substitution rate is 25%,the compressive strength is the most significant,and the strength of 7D and 28 d increases by19.7% and 6.3%,respectively.(3)through the engineering application of C50 mechanism sand self compacting concrete,the results show that the workability and strength of the concrete meet the designrequirements,and the molding effect is good and the cost is reduced.