Influence of specimen dimensions and reinforcement corrosion on bond performance of steel bars in concrete

Abstract

To study the deterioration of bond performance between concrete and corroded steel bars with designed corrosion levels of 0%, 0.5%, 1.0%, 2.0%, 5.0%, 8.0%, and 10.0%, pull-out tests were performed on cube specimens with the dimensions of 10 D × 10 D × 10 D, where D is the diameter of longitudinal rebars ( D = 14, 20, and 25 mm, respectively). The experimental results indicated that with the specimen dimensions increased, the expansive cracks induced by corrosion products appeared earlier and the maximum expansive cracking width was larger at the same corrosion levels. The bond strength and the initial bond stiffness first increased and then dramatically decreased as the concrete deterioration and reinforcement corrosion levels increased for each specimen dimension, whereas the specimens with the larger diameter ( D = 25 mm) were more sensitive to the corrosion than those with the smaller diameter ( D = 14, 20 mm). The free-end slip and the energy dissipation for each specimen dimensions, which decreased slowly with increasing corrosion levels before the corrosion-induced cracks and then weakened rapidly when the corrosion-induced cracks appeared, was almost independent of the influence on corrosion levels after the corrosion-induced cracks appeared. Based on the experimental results, a simplified expression for the calculation of residual bond stress and an empirical model of the bond–slip constitutive equation that considers the influence of reinforcement corrosion were proposed, which can be used in finite element analysis of corroded reinforced concrete.

Bonding of Steel Bars in Concrete with the Addition of Carbon Nanotubes: A Systematic Review of the Literature

“…The author chose to use specimens with the same dimensions usually employed in compressive strength tests. At this point, it is noteworthy that there are studies in the literature evaluating the specimen characteristics' influence on the pull-out test and pointing to different experimental results when using varied geometries (cubic, prismatic, or cylindrical) [65,66].…”

Macro-strain based deflection and neutral axis position monitoring of reinforced concrete beams during corrosion

“…This phenomenon keeps on increasing with the higher levels of corrosion. Many researchers studied the load-carrying capacity (Coronelli and Gambarova, 2004; Rinaldi et al, 2010), ductility (Mangat and Elgarf, 1999), shear performance (Wang et al, 2011), and bond and anchorage (Zhang et al, 2020) of corroded RC beams. The majority of the works done have focused on corrosion damage under no sustained load (Shen et al, 2019).…”

Bond position function between deformed steel bars and early-age cementitious grout

“…Several studies have been performed on the material properties of cementitious grout, accompanied by the wide application of these grouts in engineering (Krishnamoorthy et al, 2002;Liu and Song, 2006;Sahmaran et al, 2008). When strengthening concrete structures with cementitious grout, however, efficient durable bonding between the steel bars and the cementitious grout is a prerequisite for monolithic action of these two different building materials (Zhang et al, 2020;Park and Paulay, 1975;Xu et al, 1994) . The research on the bond performance between reinforcement and cementitious grout can provide theoretical support for the study of bearing capacity of reinforcedconcrete members strengthened with cementitious grout, and plays a critical role in the effective application of cementitious grout in the reinforcement of existing concrete structures.…”