Ion-transport characteristics of new-old concrete composite system

New-old concrete composite system usually exists in concrete repairing structure. In the present work, series of experiments were carried out to investigate permeability and ion diffusion properties of new-old concrete composite by measuring 6-hour coulomb charge and chloride diffusivity. The interrelation among transport properties of new-old composites, new, and old concretes was also discussed. Results indicate that the permeability and chloride diffusivity of new-old concrete composite system closely interrelate to the corresponding new concrete and old concrete. The interfacial transition zone between new concrete and old concrete greatly influences the transport property of new-old concrete system. Compared with the corresponding new concrete and old concrete lower permeability and diffusivity values for the new-old concrete composites can be achieved by choosing suitable new concrete. It is possible to design the tailor-made new-old concrete composite system for repair given the transport property.