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Ports and harbours generally consist of several facilities and major infrastructures including quays, oil-handling bases, piers, bridges, wharves, warehousing, pipelines, industrial facilities and stationary offshore structures. These infrastructures are constantly exposed to the corrosive influence of seawater. Under these conditions, mutually supplementary coatings and cathodic protection systems (Hartt, 2012; Zakowski, 2011) are not very effective, though, in many cases, they are used in the design and maintenance of such infrastructures and other facilities. The seawater environment provides a severe corrosive environment to which the protection technology should be adjusted, based on the corrosion risk (Al-Malahy and Hodgkiess, 2003; K. Zakowski et al., 2014). The harbour infrastructures are normally subjected to highly abrasive or aggressive environments, especially with the holds of bulk carrier ships.
Corrosion in the port and harbour areas presents a threat to the safety of the infrastructures and to their functionality. Corrosion may also change their elastic and dynamic properties, thereby affecting serviceability. Steels left unprotected in these environments quickly start corroding and may be severely damaged within only a few years (Melchers, 2009). Corrosion in the port and harbour areas may be accelerated through pollution which may result due to power stations and other industries present in these areas. Pollution can increase the corrosion of steel, reinforced concrete and other engineering materials which make up the infrastructure assets (Marcos et al. 2006).
Steel corrosion and the deterioration of protective coating of infrastructures in marine coastal environments have been studied worldwide and various types of studies have been performed. Many of these studies have focused on the corrosion degradation of steel piles. In Swedish harbours, for example, it was observed that the influence of salinity on the corrosion rate of the steel sheet piles is not clear. Their corrosion rate was found to vary between 0.01 and 0.35 mm/year at different locations (Wall and Wadsö, 2011). Similar studies were performed in other regions such as the Southern Baltic Sea, Mexico and Israel (Zakowski et al., 2014; Garcia et al., 2010). Microbial induced corrosion (MIC), which is the main type of corrosion encountered on piles and other port infrastructures has also been vastly studied. MIC leads to extremely high corrosion rates. They have been observed to increase to more than ten times the normally expected corrosion rates. This may exceed by far the much lower conventional design allowances of 0.1– 0.5 mm/year (Melchers and Jeffrey, 2013) attributed to the structures. It was also found that the discharge of municipal, industrial and agricultural effluents, which contains and produce toxic and highly corrosive components by biological and chemical decomposition, leads to corrosion which affects fixed and mobile infrastructures, including ships and ports and shipyard (Gracia et al, 2010; Wiener and Salas, 2005).
Apart from piles, other types of infrastructures have also been studied. In Kuwait, for example, seawater has been found to be the main factor causing marine corrosion. It is consumed for cooling and other purposes by industries such as oil refineries, petrochemical industries, water desalination plants and power generation stations because it is easily available and is cost effective. It has been found that corrosion prevention and treatment for such industries cost more than 20% of a typical industrial budget (M. Hajeeh, 2003). Nowadays, research is being carried out to use more effective corrosion prevention methods. Such methods consist of corrosion resistant coatings, novel coatings and corrosion resistant materials, for example use of thermal spray of inconel 718-Al2O3 composite coatings and use of titanium instead of more corrosion prone metals (Singh et. al., 2020; Vasudev et. al., 2021a; Vasudev et. al., 2021b; Vasudev et. al., 2021c)