Effect of Cracking on Corrosion of Steel in Concrete

Abstract

It is generally recognized that cracks provide easy access to ingress of chlorides in concrete and hence, the initiation of corrosion of steel in cracked concrete occurs at early stage. However, wide variety of results on the effect of crack widths on corrosion of steel in concrete are reported in many studies. Apart from crack width, the crack depths, cracking frequency and healing of cracks also influence the corrosion of steel in concrete. This paper presents a comprehensive review and summarised the results on the effect of cracking on corrosion of steel in concrete. The effect of crack widths on the diffusion of chlorides ions and carbon-dioxide is also discussed in this paper. Among all available results, a correlation between the corrosion current and the crack widths up to 0.3 mm can be established, however, no distinct trends are observed beyond that crack width. Conflicting results on the effect of crack widths on chloride ion diffusion are also reported. The longitudinal crack causes more severe corrosion of steel in concrete than transverse cracks of same width. Cracked concrete containing supplementary cementitious materials exhibited superior corrosion resistance than cracked ordinary Portland cement concrete of same width of transverse as well as longitudinal cracks. The same is also true in the case of lower water-binder ratios of cracked concrete. The increase in crack depth increased the chloride diffusion; however, the corrosion test shows an opposite trend. Conflicting results on the effect of crack frequency on corrosion of steel are also reported.

Effect of Mill-Rejected Granular Cement Grains on Healing Concrete Cracks

“…Crack formation in concrete could affect the strength, durability, serviceability, and aesthetics of a concrete structure. If concrete cracks are not treated properly, they may lead to a complete failure of the structure [4][5][6] by allowing the ingression of chemical solutions detrimental to concrete. Some of the common chemical attacks on concrete are delayed ettringite formation due to the ingression of excess sulfate, corrosion of reinforcement due to the ingression of chloride ions, and an alkali-silicate reaction.…”

Longitudinal restraining devices for the evaluation of structural behaviour of cement‐based materials: The past, present and prospective trends

“…These volumetric changes are, almost inevitably, restrained to a certain degree in structural applications, generating tensile stresses, which if they exceed the tensile strength of concrete at a time instant, will cause cracking. Such cracking, referred to hardening‐induced or early age cracking, may be detrimental for the durability of the concrete or affect the serviceability of a concrete structure 2–5 …”

Corrosion testing on steel reinforced XD3 concrete samples prepared with a green inhibitor and two different superplasticizers

“…Cracking of the concrete cover is a critical limit state and this is often modeled as a two‐stage process that consists of (a) an initiation phase, defined as the time taken for corrosion to commence and (b) propagation phase, where the accumulation of corrosion products induces expansive stresses and damage . Until recently, most research has focused on the time up to corrosion initiation, while the propagation phase leading to failure remains poorly understood as it is stated in a recent report of Wong et al…”