Crack formation and chloride induced corrosion in Reinforced Strain Hardening Cement-based Composite (R/SHCC)

This paper reports on corrosion of reinforcing steel bars in strain hardening cement-based composites (SHCC) under chloride attack. As part of a continued research project on durability of SHCC, the main focus here is on flexurally induced cracks in reinforced SHCC (R/SHCC) specimens with different cover depths. After unloading from the flexural test, these specimens are subjected to chloride attack, while monitoring steel corrosion. The R/SHCC specimens comprised series manufactured with two different types of sand, reinforced with single and double tensile steel bars with three different cover depths, in order to relate the crack patterns, cover depth and rebar corrosion. Crack widths of below 50 μm are found to allow chloride penetration to the rebar within hours. Corrosion potential and corrosion rate measurements, following a Coulostatic method, are reported. By removal of rebars from a number of specimens after more than a year of chloride exposure, corrosion damage is studied by visual observation, pitting depth measurements and tensile testing of the rebars. Chloride profiles are also determined through XRF in cracked and uncracked regions of the specimens. Relation of corrosion damage calculated from corrosion rate measurements, with observed corrosion damage is complicated by localised corrosion.