Bond of naturally corroded, plain reinforcing bars in concrete

Abstract

In the past, reinforced concrete structures were built utilising plain reinforcement bars. Currently, this construction method is seldom considered by codes and research; however, many heritage structures are still standing and in need of proper assessment. In particular, there is a lack of knowledge on the effect of corrosion on the bond between concrete and plain reinforcement bars. To address this gap, pullout tests were performed on reinforced concrete specimens sourced from a decommissioned bridge originally constructed in 1935. The specimens were naturally corroded, as the use of accelerated corrosion techniques in structural tests is still debated.A total of 156 pullout tests were conducted on specimens with varying thicknesses. The pullout force, active and passive slip, and corrosion levels were measured. The effect of corrosion on the bond strength, and the amount of visible damage owing to the presence of corrosion products, were influenced by the casting position of the reinforcing bars. The presence of stirrups influenced the postpeak behaviour, increased the residual bond strength, and helped maintain the bond strength in the presence of cracks and spalling damage. Additionally, current code provisions were found to provide conservative values for the peak bond stress of plain reinforcing bars.

Impact of Corrosion on the Bond Strength between Concrete and Rebar: A Systematic Review

“…The most prominent and realistic conditions are obtained when using naturally deteriorated specimens to investigate the influence of corrosion. The authors [ 16 , 17 , 18 , 19 ] studied the effect of corrosion on the end anchorage by performing a four-point bending test on decommissioned edge beams from Stallbacka (Sweden). However, testing specimens from a decommissioned structure can be challenging because the influential factors are likely uncontrollable.…”

“…On the other hand, researchers investigated the bond deterioration of corroded specimens extracted from decommissioned RC bridges [ 16 , 17 , 18 , 19 ]. Tahershamsi et al [ 17 ] examined the bond degradation due to corrosion-induced crack widths of 32-year-old naturally corroded RC girders.…”

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

“…Previous investigations on real decommissioned edge beams taken from two bridges in Sweden (Robuschi, Sumearll, Fernandez, & Lundgren, 2020;Tahershamsi, Fernandez, Lundgren, & Zandi, 2017) have reported extensive cover cracking and spalling due to corrosion. Based on this, the corrosion propagation time in the present study was mainly predicted using a corrosion-induced cracking model.…”

Effect of pre-existing longitudinal and transverse corrosion cracks on the flexural behaviour of corroded RC beams

“…The regression coefficients ranged between 0.74 [26] and 0.97 [27]. Furthermore, many studies were dedicated to investigating the effect of corrosion on the bond between the concrete and the steel [21,[28][29][30][31][32] and its effect on the structural behaviour of corroded beams in bending. Bond deterioration and cover cracking affect the stress transfer between the steel and the concrete, which in turn is manifested by increased deflections, fewer and wider bending cracks for corroded beams failing in flexure [17,26].…”