On the role of deterioration of structures in their performance; With a focus on mining industry equipment and structures

Some examples of materials performance of civil materials such as steel and concrete in mining industry are considered. These examples are about structural steels (either as support for the structure or the equipment) and concrete structures. Also, it is mentioned that in mine sites that contain sulphide minerals, the formation of acid mine drainage (AMD) may also contribute to decreasing the integrity of civil and supportive structures. Using these examples, an effort has been made to emphasise that in order to extend the service life of structures in very aggressive environments such as those encountered in mining industry, a sound knowledge of deterioration and corrosion-enhancing factors in addition to standardised application of measures against deterioration (such as painting) can be very applicative. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

On the impact of algae on accelerating the biodeterioration/biocorrosion of reinforced concrete: A mechanistic review

In this paper, the complexities involved in both microbiologically influenced corrosion and deterioration of reinforced concrete structures by algae are explained. In this regards, the five possible corrosion/deterioration mechanisms that may be expected are addressed and described. These mechanisms are as follows: Absorption of some chemicals necessary for the algae from within the cement paste of the concrete: this mechanism can finally result in drying out the concrete and developing cracks as a result of formation of internal cavities and voids. Biofilm formation and increasing the likelihood of attracting more micro-/macroorganisms that can either deteriorate the concrete itself or the reinforcement steel inside, or both. An example as such can be development of an environment favorable for the acid-producing sulphur oxidizing bacteria that through generating very acidic conditions are capable of doing harm to both metallic and non-metallic phases of the reinforced concrete. Development of electrochemical cells such as differential aeration cells due to the photosynthetic driven oxygen production and consumption features of algae. In this way, it is likely that spots of varying oxygen partial pressures will be created, tus facilitating the corrosion of the steel inside. Production of acids that can be detrimental to the mechanical integrity of both concrete and steel reinforcement. Production of alkaline conditions that upon varying and fluctuating due to the chemistry of the system, can protect the concrete but do damage to the steel phase via mechanisms such as caustic embrittlement. The aim of this review paper is to gather all possible mechanisms that may be involved in explaining the contribution of algae to the bio-corrosion/bio-deterioration of reinforced concrete

Biofuels-related materials deterioration in biorefineries, transportation and internal combustion engines: A technical review

Biofuels, like any high-affinity chemical mixtures; can cause tribological effects at interfaces with metallics (ferrous-nonferrous) and non-metallics due to medium assisted activation of corrosion by unsaturated components. The damages; corrosion and tribological effects on surfaces (abrasive wears and edge/cosmetic corrosion), also include contamination and biofuels replacement due to quality decrease. The most common phenomena include the oxidation of biodiesel which increases its affinity towards metallic counterparts, i.e. automotive parts or processing apparatus, via formation of peroxide compounds by oleic acid, linoleic acid, and linolenic acids. This corrosion receptive medium causes pitting; due to high water content and high electronegativity of dissolved oxygen, and galvanic corrosion; due to high electrical conductivity. The main factors for higher aggressive corrosivity of biofuels can be summarized as high electrical conductivity, polarity, solubility, and hygroscopicity. This paper closely reviews the materials deterioration in contact with biofuels and possible corrosions

Corrosion of a drilling pipe steel in an environment containing sulphate-reducing bacteria

In this study, the microbiologically influenced corrosion caused by sulphate-reducing bacteria (SRB) has been studied. The material tested was a drilling pipe steel designated as N-80. Weight loss studies and potential measurements were carried out in two types of culturing solutions, with and without SRB inoculated. From weight loss studies, corrosion rate in SRB inoculated solution has been found to be roughly six fold greater than that in the medium without SRB. Also under the investigated conditions, the effective concentration of biocide necessary to control corrosion of N-80 steel in the presence of SRB, has been found to be at least 500 ppm. (C) 1997 Elsevier Science Ltd