Neutron diffraction studies on strain evaluation of rebar in reinforced concrete

Suzuki, Hiroshi  ; Kanematsu, Manabu*; Kusunoki, Koichi*

It is typical method to measure the strains on a rebar in a reinforced concrete using strain gauges glued on the rebar. The waterproof treatment and wiring of the strain gauges, however, would affect the accuracy of the strain evaluation of the rebar in the reinforced concrete. In this study, neutron diffraction technique, which is nondestructive and noncontact technique, was applied to the strain evaluation of the rebar in reinforced concrete in order to solve above problems. It was confirmed that the absorption coefficient of concrete is smaller than that of steels, and that the effect of absorption of concrete on the accuracy of strain measurement is low. We measured strain distribution of the rebar in reinforced concrete, and the size of anchorage zone was evaluated. It was confirmed that the size of anchorage zone evaluated using neutron diffraction was smaller than that evaluated using strain gauges.