Study On The Application Of Tuff Machine-made Sand And Powder In Commerical Concrete

For the past few years,China’s investment in infrastructure and realty has always maintained a steady growth rate,which drives the sustained and rapid development of the commercial concrete industry.As an important part of the concrete raw materials,the quality of manufactured sand is closely related to the quality of concrete.River sand was mainly used for construction sand previously,but with the strengthening of people’s resource protection awareness and relevant national environmental protection measures,natural sand can no longer meet the demand for the large construction market.The development trend of the concrete industry is that manufactured sand as fine aggregate will instead of natural sand.However,the quality of manufactured sand will be different due to the characteristics of parent rock,the choice of crushing machinery and the technical level of manufacturers.Therefore,in order to guide the engineering application in local area,it is necessary to carry out targeted test research for the popularization and application of manufactured sand.This paper study on the workability of mixture,mechanical property,durability of tuff manufactured sand concrete under different mixing,then analyzes the most valuable manufactured sand ratio both comprehensive cost and technology.In order to optimize the performance of manufactured sand concrete,through the influence of tuff powder on the performance of cement,then optimal amount of tuff powder was obtained.The test results indicated that:(1)With the increase of the amount of admixture of the tuff manufactured sand,the performance of workability on the concrete is overall reduced,which shows the weakened fluidity and the slight water refreshing phenomenon under the large mixing amount.Under the same proportions of concrete mixture,the compressive strength of tuff manufactured sand concrete is slightly lower than that of natural sand concrete,and the strength of concrete using all manufactured sand grows rapidly in the later stage,and gradually narrowing the gap with natural sand concrete.The standard curing period of 90 d is 94% of the compressive strength of natural sand concrete at 90 d.(2)Analysis of concrete durability,the effect of manufactured sand mixing on frost resistance is not obvious,all the tuff manufactured sand concrete can reach above F225,when chlorine erosion and freezing and thaw cycle,concrete mixed with limestone manufactured sand reached the first damage standard,but all mixing can meet the requirements of the minimum F50 antifreeze concrete.In the dry and wet cycle test of the composite salt solution,with the increase of sand mixing of the tuff mechanism,The value of Ff is increases first and then decreases,and the concrete is most seriously eroded when the mix is40%.Comprehensive two aspects of cost and quality two aspects,100% mixed with tuff manufactured sand concrete meets the requirements of the research.(3)The study of the influence of tuff powder on cement performance shows that with the increase of stone powder mixing,the standard consistency water consumption increases,the condensation time increases and the flow value of cement sand is> 20%,the volume stability test is 30% at 20%.(4)The mixing control of tuff powder within 10% can significantly improve the ease of mechanical sand concrete mix and provide better quality assurance for the application of tuff manufactured sandstone concrete in commercial concrete;With the increase of stone powder mixing,the compressive strength of manufactured sand concrete increases first and then decreases,amount of admixture of tuff powder is 5% which reached the peak,and when mixed amount control within 10% has good freezing resistance,and mixing amount control at about 5% is more conducive to improving the erosion ability of composite salt solution(5%Mg SO4 with 3%Na Cl)of mechanical sand concrete.