摘要
This article presents freeze-thaw(F/T)resistance of concrete containing recycled concrete aggregate(RCA).RCA percentages of 15%,30%,45%,and 60%were replaced by natural aggregate.Air entraining admixture(AEA)with three different ratios(0.06%,0.13%,and 0.20%)were used and three different maximum aggregate particle sizes(dmax=16 mm,22.4 mm and 31.5 mm)were selected.F/T resistances of the concretes were determined through the measurement of scaling on the surfaces of the samples placed in 3%NaCl solution in pursuance of TS CEN/TS 12390-9.It was observed that the compressive strength of the concretes decreased by 20%on average compared to the control samples with the increase in the amount of RCA.However,it was determined from the experiments that the use of RCA increases the F/T resistances of the concretes as it provides extra voids in the concrete and decreases capillary permeability.Within the limits of this study,d_(max)=22.4 mm,RCA=45%and AEA=0.13%are recommended as the optimum values for F/T resistance of the concrete.It is also recommended to use RCA in pavement applications including roadways,highways,parking facilities,and other non-structural concrete elements subjected to severe winter conditions.
