Stress distribution measurement along rebar embedded in concrete using neutron diffraction

Suzuki, Hiroshi  ; Kusunoki, Koichi*; Harjo, S.   

In modern society, architectural and civil engineering structures such as reinforced concrete buildings require high seismic performance to minimize the "megarisk" exposed from urban earthquake hazards. In the reinforced concrete structures, the bond resistance between rebar and concrete is one important parameter for discussing its performance and it has been typically evaluated by measuring the strain distribution along the embedded rebar. However, it is difficult to evaluate the bond resistance accurately by strain gauges due to deterioration of bonding around the strain gauges. Here we present an in-situ strain and stress measurements for the rebar in the reinforced concrete using time-of-flight neutron diffraction as a novel alternative technique to typical strain gauges. It was demonstrated in this study that the three-dimensional deformation behavior of the embedded rebar in normal-strength concrete, cured in air, can be accurately measured under pull-out loading using time-of-flight neutron diffraction.