Properties of recycled aggregate concrete with different water control methods

The paper studies the properties of Recycled Aggregate Concrete (RAC) with four different water control methods: the control group, pre-wetting with the same total water amount group, pre-wetting with the same mixing water amount group and adding extra mixing water group. Macro properties of concrete materials, i.e., compressive strength, drying shrinkage and chloride penetrability, and micro properties of Interfacial Transition Zone (ITZ), i.e., length and elastic modulus, are tested. The results show that RAC with a pre-wetting process has lower compressive strength and a higher Cl− diffusion coefficient, but a smaller shrinkage value compared to RAC with the same total water amount and no pre-wetting process. Adding extra mixing water process weakens the properties of RAC. The comprehensive elastic modulus is defined as an integrated interface parameter, and it has a good correlation with the macro properties like compressive strength and diffusion coefficient of Cl− of RAC.