Quick water movement around concrete cracks under unsaturated conditions

• From experiment, water movement in a crack decelerates dramatically in minutes.
• From experiment, water movement around a crack is expressed in the quadratic root of time.
• Water content profiles do not show the popularly known one at the early phase.
• Water movements in cracks are similar to water movements into concretes in this study.

The purpose of this research is to detect the water penetration, especially around concrete cracks, under unsaturated conditions at an early time by neutron radiography. The previous known theories of water movement in concrete are verified by the experimental results, both in cracks and around cracks. The results show that water movement in a crack decelerates dramatically in minutes. They also indicate that water movement in some kinds of concrete cracks should be treated in the same way as water absorption into concrete, which described diffusion dominated inflow only after a few minutes.