Quantification of water penetration into concrete through cracks to rebars by neutron radiography
ABSTRACT: Improving the durability of concrete structures is one of the ways to contribute to the sustainable development of society, and it has also become a crucial issue from an environmental viewpoint. It is well known that moisture behavior in reinforced concrete is linked to such phenomena as cement hydration, volume change and cracking caused by drying shrinkage, rebar corrosion, and water leakage that affect the durability of concrete. In this research, neutron radiography (NRG) was applied to visualization and quantification of water penetration into concrete through cracks. It is clearly confirmed that NRG can make visible the water behavior in/near horizontal/vertical cracks and can quantify the rate of diffusion and concentration distribution of moisture with high spatial and time resolution. And experimental research was conducted to demonstrate water supply from a crack to a rebar, and water behavior around the rebar was visualized and verified using unsteady diffusion model based on microstructures. And also the hydraulic diffusivity coefficient was obtained by NRG.