We have developed portable 950 keV/3.95 MeV X-ray/neutron sources and applied them to inspection of PC concrete thicker than 200 mm within reasonable measuring time of seconds - minutes. T-girder-, Box- and slab- bridges are considered. Now we are to start X-ray transmission inspection for highway PC bridge (box) by using 3.95 MeV X-ray sources in Japan in 2020. By obtaining X-ray transmission images of no-grout-filling in PC sheath and thinning of PC wires, we plan to carry out numerical structural analysis to evaluate the degradation of strength. Finally, we are going to propose a technical guideline of nondestructive evaluation (NDE) of PC bridges by taking account of both X-ray inspection and structural analysis. Further, we are trying to detect rainwater detection in PC sheath, and asphalt and floor slab by the 3.95 MeV neutron source. This is expected to be an early degradation inspection. We have done preliminary experiments on X-ray transmission imaging of PC wires and on-grout-filling in the same height PCs in 450–750 mm thick concretes. Moreover, neutron back scattering detection of water in PC sheath is also explained.
Part of the book: Computational Optimization Techniques and Applications