Study On The Durability Of The Yellow River Super Fine Sand Concrete

The special fine sand resources in the coastal area of the Yellow River are rich,and incorporation of some Yellow River extra fine sand as the fine aggregate concrete has been widely used in Zhengzhou and its surrounding areas.There is no uniform standard for the Yellow River Super fine sand in concrete content,the present study is relatively small about the influence of Yellow River Super fine sand on the mechanical properties and durability of concrete.The durability of concrete is very important,which directly affects the safety and reliability of the concrete structure.This paper will carry out the research on the durability of the Yellow River super fine sand concrete,and analyze the influence of the Yellow River super fine sand on the durability of concrete,and provide theoretical basis for the application of the Yellow River super fine sand in the concrete.This paper based on the Yellow River Super sand and the mechanism sand in different proportions of concrete,research the influence of Yellow River Super fine sand for aggregate gradation,mechanical properties of concrete,concrete microstructure and durability of concrete.This paper selects influence the durability of concrete carbonation,freeze-thaw,chloride ion penetration of three main factors,design the durability test plan and method,through the test studied Yellow River Super fine sand concrete carbonation,frost resistance and resistance to chloride ion permeability,revealed their mechanism of action.The main research contents are as follows:(1)The scanning electron microscope test of the Yellow River Super fine sand concrete was carried out,the influence of different the Yellow River Super fine sand content on the microstructure of concrete was analyzed,and the development law of the microstructure characteristics of concrete was studied.The results show that: the microstructure of the concrete is the most compact,the aggregate and the cement paste interface are the best,and the crack and porosity are the least,when the Yellow River Super fine sand replacement mechanism sand was 15%.(2)The carbonation test of the Yellow River Super fine sand concrete was carried out,the effect of different the Yellow River Super fine sand content on the carbonation of concrete was analyzed,and the neutral rule of concrete under carbonation was studied.The results show that: the carbonation rate of concrete was the slowest when the Yellow River Super fine sand replacement mechanism sand was 15%.(3)The fast freeze-thaw test of the Yellow River Super fine sand concrete was carried out,the effect of different the Yellow River Super fine sand content on the freezing and thawing was analyzed,and the freeze-thaw of concrete mass loss,dynamic elastic modulus variation was studied.The results show that: the frost resistance of concrete was best when the Yellow River Super fine sand replacement mechanism sand was 30%.(4)The resistance to chloride ion penetration test of the Yellow River Super fine sand concrete was carried out,the effect of different the Yellow River Super fine sand content on the chloride ion penetration of concrete was analyzed,and the chloride ion erosion under the action of concrete chloride ion diffusion was studied.The results show that: the chloride ion erosion rate of the concrete was the slowest when the Yellow River Super fine sand replacement mechanism sand was 15%.