High‐cycle fatigue behaviour of reinforcing steel under the effect of ongoing corrosion

Abstract

High-cycle fatigue behaviour of reinforcing steel under the effect of ongoing corrosionThis paper presents the results of the corrosion fatigue behaviour of profiled reinforcing steel bars. Cyclically loaded rebar was simultaneously exposed to different corrosive environments -moderate to severe corrosive environments simulating XC or XD/XS exposure. Corrosion was configured naturally without any external polarization. Rebar was exposed to the corrosive solutions either directly or, when embedded in concrete, indirectly. In this latter case, corrosive agents penetrated towards the steel surface through an open crack. Low frequency was applied to enable extended corrosion periods. The potential drop method was utilized to detect and quantify the crack initiation and crack growth of the rebar. Using this method it was possible to determine the ratios between the number of cycles to crack initiation and the cycles to failure. Based on this method, the N ini /N F ratios were almost always between 0.8 and 0.9 -values that are similar to ratios determined for rebar tested in air (reference). This indicates that the fatigue life of rebar in carbonated concrete or concrete containing chloride is strongly dependent on crack initiation and less on crack growth. The S-N curves derived from the corrosion fatigue tests deviate significantly from the curve that was measured during the reference fatigue tests (tests in air). The S-N curves of rebar tested under corrosion fatigue load were linear, with a slope that was much steeper than the slope of the reference rebar tested in air.

An Approach to Predict Geometrically and Thermo-Mechanically Induced Stress Concentrations in Ribbed Reinforcing Bars

“…Several studies addressing the relationship between rib geometry, stresses at the rebar surface induced by service loads and the rebar fatigue performance have been conducted [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. The rib volume and the foot radius of the transverse rib were identified to have the main impact on the rebar fatigue performance.…”

Untersuchungen zur Prüfmethodik bei Dauerschwingversuchen von Betonstahl

“…Des Weiteren sorgt die Korrosion von Betonstahl in Beton für eine Aufrauung des Stahls und damit für eine Vielzahl an Mikrokerben, die zu einem verfrühten Versagen bei kombinierter Einwirkung mit Dauerschwingen führen können. Dies zeigten Untersuchungen an in Lösung [11] sowie einbetoniert [12, 13] geschwungenen Betonstahlproben.…”

Fatigue reliability evaluation of aging prestressed concrete bridge accounting for stochastic traffic loading and resistance degradation

“…Garbatov et al (2014) conducted fatigue strength experiments on corroded rebars and found a direct relationship between the initial corrosion surface roughness and the pit depth. Gehlen et al (2016) demonstrated that the slope of the S-N curve was steeper in a corrosion fatigue environment for rebar. Lan et al (2018) proposed a Weibull model of the C-S-N (Corrosion S-N) relationship for steel rebar, which was subsequently utilized to evaluate the influence of corrosion on the fatigue life.…”