Study on the effect of recycled sand quality and replacement ratio on additional water consumption and mechanical properties of concrete
[Objective]Additional water is added to the recycled concrete to compensate for the water absorption of recycled ag-gregates,and its amount has an important influence on the properties of recycled concrete.In order to explore the influence of the quality and replacement ratio of recycled sand on the value of additional water consumption and basic mechanical properties of re-cycled concrete.[Methods]By adjusting the additional water consumption to make the fresh concrete have similar working per-formance,the additional water consumption and mechanical properties of recycled concrete prepared by replacing natural sand with 30％,50％and 70％mass fractions of class Ⅰ,class Ⅱ and class Ⅲ are compared and studied.[Results]The result show that the additional water consumption increases linearly with the increase of the replacement rate of recycled sand,the additional water consumption and the additional water consumption compensation coefficient increase with the decrease of the quality of recy-cled sand,and the additional water consumption factors of class Ⅰ,class Ⅱ and class Ⅲ recycled sand are 0.62,0.84 and 0.96,respectively.With the decrease of the quality of recycled sand or the increase of the replacement ratio,the recycled concrete com-pressive strength,flexural strength and modulus of elasticity keep decreasing,and the quality of recycled sand and replacement ratio have the greatest effect on flexural strength.Reducing the quality of recycled sand or increasing the replacement ratio of recycled sand generally reduces the flexural-compression ratio of concrete,that is,the brittleness increases.[Conclusion]It can be consid-ered that the additional water consumption compensation coefficient of recycled concrete should be adjusted according to the quality of recycled sand:low-quality recycled sand should take a higher additional water consumption compensation coefficient value,and high-quality recycled sand can appropriately reduce the additional water consumption compensation coefficient;The incorporation of recycled sand increases the brittleness of recycled concrete,and when recycled concrete is used as a stressed component mainly bending resistance,it is necessary to reduce the replacement rate of recycled sand or use high-quality recycled sand.
quality of recycled sandconcreteadditional water consumptionmechanical propertiesstrength
万方数据
维普
