Corrosion-induced Delamination Research Articles

The combined effect of stress and corrosion on mild steel

This paper reports confirmation of the effect of different levels of tensile stress caused by quasi-static loading on corrosion growth and the mechanical properties of corroded steel. Plastic stressed, elastic stressed and non-stressed specimens have been immersed into hydrochloride acid with acidity ranging from 0.00001 to 1 Molar. Corrosion behaviours of the test specimens are measured after 7, 14 and 28 days. The mechanical properties of steel are then measured at three grinding thicknesses (0, 0.5 mm, and 1.5 mm) at different stress and corrosion combined environments to determine the effect of stress and corrosion on mechanical properties of steel and the corrosion penetration depth. Results show that the applied stress, especially plastic stress, can accelerate corrosion and contribute to the growth of corrosion-induced delamination. The results demonstrate that there are higher degrees of degradation in mechanical properties and faster growth of corrosion penetration depth for plastic stressed steel than elastic stressed and non-stressed specimens over time. The relevant mechanisms are summarized in this paper. This paper attempts to explain of cause-effect relationships between the level of imposed stress, the level of corrosion and the mechanical properties of corroded steel.

Rational Condition Assessment of RC Bridge Decks Subjected to Corrosion-Induced Delamination

AbstractPrecise evaluation of the condition of RC bridge decks, particularly for corrosion-induced delaminations, is decisive for ensuring bridge performance and safety. Although infrared thermogra...

Retraction Note: Investigation of coating delamination on steels by surface topography and Volta potential difference

Corrosion-induced delamination of an epoxy coating on the AISI/SAE 1045 carbon steel was studied under a humid atmospheric condition (temperature of 25 °C, one standard atmospheric pressure, and relative humidity of 90 %) by the technique of scanning Kelvin probe force microscopy (SKPFM). Surface-polished 1045 samples were first cold coated with the epoxy and then subject to the atmospheric corrosion under the humid atmospheric condition. At specified time intervals, surface Volta potential of the samples was measured using the SKPFM over the dry surface of epoxy coating. The map of Volta potentials demonstrated high contrasts among three characteristic zones: intact steel-epoxy interface, delaminated interface, and interface with active corrosion, which based on a rigorous calibration procedure were then linked to the actual corrosion potential of the steel (measured using a potentiostat w.r.t. a saturated calomel electrode). The SKPFM was found to be able to provide a mean of direct and nondestructive detection of early active corrosion and coating delamination of steels at a submicroscopic resolution, which outperformed the conventional electrochemical techniques for such purposes.

Nondestructive Detection of Delamination in Concrete Slabs

The delamination of concrete slabs is the separation along a plane roughly parallel to, and generally near, the surface. Corrosion-induced delamination is a common problem in old concrete bridge decks. If undetected, delaminations could expand, reach the surface, and result in spalling. Early detection of delamination is necessary for planning timely repairs that prevent costly deck replacement projects. Most bridge owners rely on routine visual and traditional surveys of bridge deck conditions. These surveys are highly subjective and can locate only large shallow delaminated zones. Several nondestructive testing (NDT) techniques have recently been employed for bridge deck evaluation to obtain more objective and comprehensive assessment. The reliability of applicable methods needs to be established before a greater role for NDT in routine inspections can be encouraged. This paper presents a validation study aimed at evaluating the effectiveness of three NDT techniques, namely impact echo, ultrasound (US) echo, and US linear array, in detection of delamination. This study is unique because the subject test specimens were deteriorated bridge deck segments preserved from the demolition of a prestressed box girder bridge. The results of the tests conducted on one of the specimens are presented and discussed here: impact echo provided satisfactory overall assessment, but the individual results were often difficult to interpret; US echo detected deep delaminations but not shallow ones; and US linear array located the extent of deep delaminations and provided indications of shallow ones.

EMAT-Based Inspection of Concrete-Filled Steel Pipes for Internal Voids and Inclusions

Concrete-filled steel pipes have been used as piles for supporting civil and marine structures. These piles provide good bending resistance, and can be easily spliced for long depth installation. However, these piles are usually exposed in hostile environments such as seawater and deicing materials. Thus, the outside corrosion of the steel pipe can reduce the wall thickness and the corrosion-induced delamination of internal concrete can increase internal volume or pressure. In addition, the void that can possibly exist in the pipe reduces the bending resistance. To avoid structural failure due to this type of deterioration, appropriate inspection and repair techniques are to be developed. The acoustic method is attractive for this inspection since it is relatively simple and versatile. Especially, guided wave techniques have strong potentials for this inspection because of long-distance inspection capability. There are different transducer-coupling mechanisms available for the guided wave inspection techniques. Electro-magnetic acoustic transducers (EMATs) give relatively consistent results in comparison to piezoelectric transducers since they do not need any couplant. EMATs are used for transmitting and receiving cylindrical guided waves through concrete-filled steel pipes. It is shown that EMAT-generated cylindrical guided wave techniques have good potential for the interface inspection of concrete-filled steel pipes.

Underwater inspection of concrete-filled steel pipes using guided waves

Concrete-filled steel pipes have been widely used as piles for supporting marine and civil structures. They provide good bending resistance and can be easily spliced for long depth installations. In addition, they have high strength and ductility and are an economical solution for bridges. However, these piles are usually exposed in water, particularly seawater, and thus the outside corrosion of the steel pipe can reduce the wall thickness and the corrosion-induced delamination of internal concrete can increase internal volume or pressure. To avoid this type of deterioration, appropriate inspection and repair techniques are required. The acoustic method is an attractive method for the interface delamination detection since it is relatively simple and versatile. Guided wave techniques have particularly strong potential for this type of inspection and the feasibility of the guided wave techniques for detecting the interface inspection is investigated in this paper. A special coupling mechanism for transmitting the guided waves is introduced for the experimental study. An analytical study is also carried out to identify the cylindrical guided wave modes that are sensitive to the interface separation. This study shows the feasibility of using guided waves for underwater inspection of concrete-filled steel pipes.

“Barrier-Adhesion” Principle for Corrosion Protection

Abstract The “barrier-adhesion” principle for corrosion protection of aluminum alloys is presented. Corrosion that occurs in a coated aluminum alloy can be viewed as pertaining to one of the two following corrosion modes: corrosion that occurs at and in the vicinity of a damaged coating (damaged surface corrosion, such as that associated with scribed corrosion testing) and corrosion that occurs under an undamaged coating, which often appears as many small pits (pitting corrosion). The damaged surface corrosion has been found to be a consequence of corrosion-induced delamination of the coating, which enhances the propagation of corrosion from the damaged site. With a coating system that contains corrosion inhibitors, the corrosion at the damaged site is suppressed to prevent delamination. It was found that if a good barrier is adhered to the metal surface by the tenacious water-insensitive adhesion, the corrosion-induced delamination can be prevented without corrosion inhibitors in the primer. Pitting corr...

Corrosion protection of cold-rolled steel by low temperature plasma interface engineering: I. Enhancement of E-coat adhesion

An anode magnetron enhanced d.c. cathodic plasma treatment of a cold-rolled steel (CRS) plate and cathodic (plasma) polymerization were used to create interface engineered systems of cathodic E-coat/plasma polymer/plasma treated CRS. The adhesion of the E-coat and the corrosion protection characteristics of the systems were compared with the control, E-coat/Zn phosphate-chromate/alectro-galvanized steel (EGS). The adhesion of the E-coat to the plasma polymer coaled CRS was found to be excellent; the E-coat could not be removed by N-methyl pyrrolidone (60 °C) in 5 days, while the same E-coat applied on the control was removed in a few minutes. The plasma polymer of trimethylsilane (TMS) was found to yield excellent corrosion protection as used in the interface engineered systems, of which the corrosion (GM scab) test was found to be better than that for the control. The plasma pretreatment of the CRS surface prior to the cathodic polymerization of TMS was found to be a critically important factor. The corrosion-induced delamination of the first paint layer seems to play a key role in the corrosion of painted steel. It was demonstrated that good adhesion and durability of the entire interface system can produce a highly corrosion resistant painted CRS.

Solid-state chemistry as applied to cathodically driven or corrosion-induced delamination of organic coatings

Solid-state chemistry as applied to cathodically driven or corrosion-induced delamination of organic coatings