Study On The Material Properties And Rheological Properties Of Tuff Manufactured Sand Cement Concrete

With the development of infrastructure construction in China,the natural sand resources is less and less.It is a general trend to use manufactured sand instead of natural sand as fine aggregate of cement concrete.However,compared with natural sand,manufactured sand has the characteristics of irregular grain shape,unreasonable gradation,and high powder content.In addition,the parent rock of manufactured sand has a wide range of lithology,and the performance of manufactured sand concrete with different lithologies is different.These problems lead to the restriction in promotion of manufactured sand concrete.Therefore,this paper conducted systematic research on tuff manufactured sand concrete,and microscopic means were used to explore the influence of tuff stone powder on cement hydration.The workability,mechanical properties and durability of tuff mechanized sand concrete were systematically studied,and the influence mechanism of tuff mechanized sand concrete on rheological properties was revealedAt the same time,the relationship model between rheological properties and workability of tuff manufactured sand concrete was established,which provides a certain research foundation for the promotion in use of manufactured sand concrete.The main research contents are as follows:Firstly,the study on the material properties of tuff powder,granite powder and fly ash was carried out.Based on the pozzolan activity index method,the pozzolan activity of tuff stone powder was evaluated and compared with the activity of fly ash and granite powder.XRD,TGDTA,SEM and other microscopic methods were used to explored the mechanism of tuff stone powder in cement-based materials.Secondly,the tuff manufactured sand gradation,stone powder content,manufactured sand replacement rate,and water-reducing agent content was set as influencing factors and the concrete strength grade characteristics were taken into consideration.The VKelly test and Slump test were carried to explore the workability of tuff manufactured sand concrete.This paper reveals the mechanism of the mechanical properties of tuff manufactured sand concrete,and perfects the research on the durability of manufactured sand concrete.Finally,based on the Bingham model,the ICAR rheometer was used to explore the influence of the characteristics of tuff manufactured sand and the mixing ratio parameters on the rheological properties of tuff manufactured sand concrete,and the mechanism analysis was carried out.The gray correlation analysis method was used to complete the significant analysis of influencing factors on the rheological properties of tuff manufactured sand concrete,the range of rheological parameters with good concrete workability was put forward,and the twodimensional and three-dimensional model of the relation between manufactured sand concrete workability and rheological properties was established.