Abstract
Fracture of reinforcing rebar due to alkali silicate reaction (ASR) of concrete has been investigated by slow strain rate test (SSRT) using a V-notched specimen simulating preexistent crack. Cathodic hydrogen charging reduced the fracture strain and facture surface showed three regions of different fracture mode, quasi-cleavage, dimple and cleavage surface from outer side to center. Specimens without cathodic charging showed only dimple and cleavage fracture surface. It suggests that hydrogen entered into rebar caused quasi-cleavage surface. Cleavage surface observed at the center part in the both cases was a result of rapid deformation and fracture of the specimen occurred just before rupture. For the hydrogen charged specimen having a sharp slit as observed on rebar fractured in ASR concrete, distribution of the three fracture mode coincided with that observed on fractured rebar in ASR concrete and hydrogen embrittlement of rebar was suggested.
