Abstract
The neutron radiography as well as X-ray radiography is one of the non-destructive evaluation methods. The difference in the permeability of the neutron ray between the hydrogen and the other element in concrete is effective to understand the moisture distribution of concrete by using the neutron radiography. The neutron radiography is usually taken by the spherical lens in the camera, and it makes the picture distortion by the inflection of light. In addition, the neutron ray is scattered, and it disturbs the result of neutron strength. This means there are some points in the neutron radiography to be improved in order to obtain the high accuracy.
Recently, in the field of reinforced concrete structures, some cracks and stress-loss of concrete structures have been reported. One of the reasons is the lack of mechanism about the volume change caused by shrinkage and creep of concrete. In order to solve the volume change of concrete, the study of moisture movement, in other words, the continual measurement of the moisture distribution in concrete is effective.
The objective of this paper is to improve the neutron radiography by considering the effect of scatterd neutron ray and the distortion of pictures. The distortion was corrected by the neutron radiography of the slit specimen made by the aluminum and the paraffin setting with the identical interval. The scattered rays were modified by the convolution of the pictures. By applying the proposed method to the plate made by mortar, the moisture distribution changing by the age was visualized clearly, and the water movement from the coarse aggregate to the mortar was estimated.
