The effect of fibres on steel bar corrosion and flexural behaviour of corroded RC beams

Artikel i vetenskaplig tidskrift, 2018

This paper reports the results of an experimental programme aimed at investigating the influence of fibre reinforcement
on the corrosion process of conventional steel rebar embedded in cracked concrete and on the
flexural behaviour of reinforced concrete beams. Un- and pre-cracked reinforced concrete beams were subjected
to natural corrosion through cyclic exposure to a 10% chloride solution for a period of three years. Subsequently,
flexural tests were carried out under three-point bending configuration. Gravimetric measurements showed
higher corrosion levels for bars in plain concrete compared to fibre reinforced concrete, and visual inspection of
the bars revealed that fibres promoted a more distributed corrosion pattern. From detailed examination of the
bars through 3D laser scanning technique, the main parameter controlling the local corrosion level of individual
pits appears to be the local interfacial conditions; grater loads during pre-cracking and repeated load cycles
yielded greater cross-sectional losses. Moreover, there was a tendency for more localized corrosion in beams
with open cracks, indicating a possible impact of crack width on the extension of corrosion. The results from the
flexural tests showed a consistent increase of load capacity for fibre reinforced beams compared to their plain
concrete counterparts but only a marginal influence of the fibres on the rotation capacity. Furthermore, the
rotation capacity of the beams was found to decrease several times faster than the load capacity with increasing
loss of rebar cross-sectional area.