Study on the influence of internal curing mechanism on the macro and mesoscopic mechanical properties of recycled concrete materials
As a green ecological concrete,recycled concrete is widely used in ecological water conservancy pro-jects.In order to improve its mechanical properties and durability,this paper pretreated the recycled aggregate to dry,semi-saturated and saturated states by internal curing method,replaced ordinary concrete with 50％and 100％substitution rates,respectively,and set up ordinary concrete in dry state as a control group,analyzed the influence of water content on the macro and mesoscopic properties of recycled concrete under different substitu-tion rates,and analyzed the correlation of various parameters,and interpreted the mechanism of internal curing from the mesoscale by establishing a water absorption and desorption model of recycled aggregate.The results show that under the same substitution rate,the recycled concrete group with 50％moisture content has the bet-ter compressive strength after curing for 90 days.The porosity of R50P and R100P decreased by 14.2％and 10.3％respectively after 90 days of curing compared with that at 7 days,indicating that the recycled aggregate with 50％moisture content could improve the porosity and interface transition zone structure to a certain extent.The internal curing mechanism of aggregate water absorption and desorption is the main reason for the continu-ous growth of the strength of recycled concrete in the later stage.
recycled concreteinternal maintenancepore structureinterface transition areawater absorption,desorption model
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