Correlation between concrete cracks and corrosion characteristics of steel reinforcement in pre-cracked plain and fibre-reinforced concrete beams

Abstract

This paper presents results on corrosion characteristics of 66 rebars extracted from un-and precracked plain concrete and fibre-reinforced concrete (FRC) beams suffering from corrosion for more than 3 years. The influences of fibre reinforcement, flexural cracks, corrosion-induced cracks and loading condition on the maximum local corrosion level (defined as the maximum cross-sectional area loss percentage) and pit morphology were examined. With 3D-scanning, the corrosion characteristics were analysed, and pit types were classified based on the maximum local corrosion level and geometric parameters of pits. Corrosion pits were observed near some flexural cracks, while the bars at other cracks were free from corrosion. Most rebars in FRC had less maximum local corrosion level than those in plain concrete under the same loading condition and maximum flexural crack width. However, the maximum local corrosion level was not dependent on the maximum flexural crack width (0.1 and 0.4 mm). Longitudinal cracks (corrosion-induced cracks) aggravated the total steel loss and changed the pit morphology by promoting the pit length development. However, longitudinal cracks did not always form, even with severe pitting corrosion. A hypothesis about the time-dependent interplay between transverse and longitudinal cracks and corrosion development was proposed. Further studies on predicting the pitting corrosion evolution and experimental work on specimens exposed for longer periods are needed to understand and quantify the long-term durability of concrete structures reinforced with both conventional reinforcing bars and fibres.

Time‐dependent cyclic behavior of reinforced concrete bridge columns under chlorides‐induced corrosion and rebars buckling

“…Corrosion scenario cases are labeled as follows: number of pits on the longitudinal rebars in‐between the transverse reinforcement/p/pitting factor—ratio between pit length and longitudinal rebar diameter in percent—ratio between loss of reinforcing steel bar cross‐section area under generalized corrosion and that due to pitting corrosion in percent. It is pointed out that pit length values in Table 1 are assumed as given numerical data for the parametric study, and they are consistent with reported experimental evidences 31,65 …”

“…It is pointed out that pit length values ℓ p in Table 1 are assumed as given numerical data for the parametric study, and they are consistent with reported experimental evidences. 31,65 The parametric analyses campaign has been planned as follows. The comparison among the cases 0p, 1p6-50-0, 1p6-150-0, and 1p8-100-0 is meant at investigating what is the difference if none or one pit in-between the transverse reinforcement spacing is assumed, taking also into account the influence of pitting factor and pit length.…”

Comparison of the service life, life-cycle costs and assessment of hybrid and traditional reinforced concrete through a case study of bridge edge beams in Sweden

“…However, structures subjected to decades of corrosion usually exhibit a mixed morphology of general and pitting corrosion. This may be because the chloride content in the region that is free of transverse cracks also reaches a threshold value to initiate corrosion, or because the earlier-corroded region near the transverse cracks spreads the corroded sites along the rebar length with the propagation of longitudinal corrosion-induced cracks, as discussed in a recent study by the authors (E. Chen, Berrocal, L€ ofgren, & Lundgren, 2020). It is a challenging task to model the evolution of the corrosion morphology and interactions between the cracks (transverse and longitudinal) and the corrosion process.…”

An Optimized Neuro-Bee Algorithm Approach to Predict the FRP-Concrete Bond Strength of RC Beams

“…This issue is particularly serious in some developed countries, where RC infrastructure components have been in use for decades [5,6]. Reinforcing steel corrosion may create cracks in the surrounding concrete owing to the expansion pressure generated during the production of corrosion products, in addition to the loss of effective cross-sectional area of the reinforcing steel [7,8]. The concrete cover may potentially spall as a result of the expansion pressure.…”