Keywords:Non Destructive Inspection, Mobile Electron Linear Accelerator, Bridge Inspection, Moisture Inspection, Neutron Source
Breakage of iron reinforcing rods in reinforced concrete structures leads to a decrease in the yield strength of the structure, which is a major factor in reducing its remaining life. Detection of moisture inside the concrete is an urgent task because the major cause of corrosion of reinforcing bars is the invasion of oxide ions and chloride ions by the liquid water reaching the rebar. In this research, a backscatter neutron moisture detection system combining a compact linac X - ray source with beryllium and helium 3 detectors as a method of moisture detection inside concrete was developed, and its ability of moisture detection was confirmed by prior experiments. In this research, the authors aim to acquire moisture distribution data inside concrete which was difficult to acquire by the existing nondestructive inspection method. The authors conducted the moisture detection and moisture content evaluation experiment using concrete samples of several water cement ratio and water content ratio as a basic study.