Mechanical properties of fly ash recycled concrete at different replacement ratio of recycled coarse aggregate
In order to discussthe influence of fly ash onmechanical property of recycled concreteat different replacement ratio of recycled coarse aggregate(RC A),and the relationship between flexural strength of recycled concrete and replacement ratio of RCA and water-binder ratio.16 groups of proportion were designed and 96 specimens were made based on the same strength RC30.The experimental studies for the compressive strength and flexural strength of recycled aggregate concrete(RAC)were conducted.The results indicate that the com-pressive strength is different with the increase of fly ash content,when replacement ratio of RCA is different.When the replacement ratio of RCA is 0、30％and 40％,the compressive strength decreases with the increase of fly ash content.When the replacement ratio of RCA is 50％,the compressive strength reduces first and then increases with the increase of fly ash content.The compressive strength of natural ag-gregate concrete(NAC)decreases sharply,while the compressive strength of recycled aggregate concrete decreases slightly,when the fly ash content exceeds 20％.Large amount of fly ash in recycled concrete may have greater application space.The deformation and failure characteristics of recycled concrete were analyzed by observing the failure section of the flexural strength specimen.The incorporation of fly ash improves the flexural strength of natural aggregate concrete,and the strength is the highest when the content is 20％.When the re-placement ratio of RCA is 30％,the flexural tensile strength decreases with the change of fly ash content,but the decline is very small.When the replacement ratio of RCA is 40％and 50％,it decreases first and then increases and then decreases.The flexural compression ra-tio of NAC increases with the increase of the fly ash content.The variation trend of flexural compression ratio with the fly ash is agreed with flexural tensile strength,while the variation amplitude is slightly small.The effect of fly ash on the flexural strength of recycled con-crete is bigger than the compressive strength.When the replacement ratio of RCA is 30％and the fly ash content is 10％,it is the preferable content.A prediction formula for the flexural tensile strength of recycled concrete is proposed.
replacement ratio of recycled coarse aggregatefly ashcompressive strengthflexural tensile strengthflexural compres-sion ratio
万方数据
维普
