Nondestructive testing of absorbed water content in 5-cm-thick concrete by neutron imaging

Since the permeation of water into concrete or the presence of water affects the deterioration of a structure, and the permeation of water affects the durability of the structure, it is important to develop a non-destructive method to quantify the movement of water inside the concrete. The authors performed imaging to acquire a transmission image by irradiating concrete with neutron rays generated by operating a small accelerator, and evaluated the relationship between the water absorption (weighing value) of the concrete and the water content shown by the transmission image. As a result, they clarified that there is a high correlation between neutron transmittance and water absorption, and proposed a method that can quantitatively evaluate, in a non-destructive manner, the permeation of water into a concrete 5 cm in thickness. (A.O.)