Freeze and thaw effect on the stiffness properties of recycled concrete aggregate used in the road embankment

Abstract

Stiffness properties affecting the road performance of recycled concrete aggregates (RCA) should be determined before using them in the road subbase and base course. On the other hand, the freeze and thaw (F-T) negatively affects the long-term performance of the road. In this study, the F-T effect on the stiffness properties of RCA obtained from the Istanbul urban transformation project was experimentally investigated. For this purpose, a series of resilient modulus and permanent deformation tests were performed on samples prepared with RCA after 1, 3, 5, 10 and 20 numbers of F-T cycles. The experiment results showed that the resilient modulus increases up to 5 F-T cycle and tends to decrease after this threshold value, that the change in plastic deformation values after F-T cycles is in the order of 0.02%, that the material exhibits plastic creep behavior. It has been determined that 100% RCA instead of natural aggregate can be used in the subbase and base by considering the relevant specifications. In addition, a model that takes into account the freeze-thaw effect and to be used in the estimation of resilient modulus for practical purposes is proposed.