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Reinforcing steel bars in concrete structures exposed to tropical marine atmospheres experience very high corrosion rates due to several environmental factors. The aim of this research was mainly to elucidate if zinc‐coated rebars may delay the onset of corrosion and/or extend the service life of infrastructure in the tropics, as the approach is promising in other atmospheres.

Hot‐dip zinc‐coated and plain steel rebars were embedded in concrete cylinders made with local aggregates and having four different water‐to‐cement ratios. Samples were exposed during 24 months at the marine breeze in a coastal site in the Gulf of Mexico. The corrosion behaviour of zinc‐coated and uncoated rebars was monitored by means of corrosion potential and linear polarization resistance techniques. Also, carbonation penetration and the chloride ingress were measured and correlated with the corrosion behaviour.

Only under the worst case conditions (concrete with 0.7 w/c ratio) did galvanized steel experience corrosion initiation. It was shown to resist higher chloride levels than uncoated steel and extended the onset of corrosion.

The effectiveness of the zinc‐coated bar for corrosion control is controversial and its use mainly is supported by accelerated tests or application in cold or subtropical environments. This research showed the corrosion behaviour in an extremely corrosive tropical zone.

The purpose of this paper is to compare the effect of rust inhibitors and surface strengthening materials on the service life of RC structures in tropical marine environments and ultimately to provide basis and recommendations for the durability design of reinforced concrete (RC) structures.

Slag concrete specimens mixed with four kinds of rust inhibitors and coated with four kinds of surface strengthening materials were corroded by seawater exposure for 365 days, and the key parameters of chloride ion diffusion were obtained by testing. Then a new service life prediction model, based on the modified model for chloride ion diffusion and reliability theory, was applied to analyze the effect of rust inhibitors and surface strengthening materials on the service life of RC structures in tropical marine environments.

Rust inhibitors and surface strengthening materials can effectively extend the service life of RC structures through different effects on chloride ion diffusion behavior. The effects of rust inhibitors and surface strengthening materials on the service life extension of RC structures adhered to the following trend: silane material > cement-based permeable crystalline waterproof material > hydrophobic plug compound > spray polyurea elastomer > water-based permeable crystalline waterproof material > calcium nitrite > preservative > amino-alcohol composite.

Using a new method for predicting the service life of RC structures, the attenuation law of the service life of RC structures under the action of rust inhibitors and surface strengthening materials in tropical marine environments is obtained.

This chapter provided systematic and comprehensive analysis on trawl fisheries management and conservation measures in the Straits of Malacca. Detailed analysis is conducted on Malaysian fishery management framework particularly domestic country's trawl fishery status, legal structure, input-control strategies, ecosystem protection plan, pollution, law enforcement, and complementary measures that designed to reduce and prevent overfishing in the exclusive economic zone (EEZ) of Malacca Straits. Gaps and challenges found in existing trawl fisheries literature are presented followed by recommendations for improvement in the management and conservation of trawl fisheries.

To evaluate the performance of two cathodic protection (CP) systems applied to steel reinforced concrete structures manufactured with calcareous aggregates and exposed to the tropical‐humid marine environment at the Yucatán peninsula in Mexico.

Rectangular concrete beams were manufactured using a water/cement ratio = 0.65, with and without the addition of NaCl in the mixing water. Specimens subjected to CP, eight to impressed current cathodic protection (ICCP) and eight to sacrificial anode cathodic protection (SACP) were partially immersed in natural seawater during 360 days. The half cell potential (HCP) and the current consumption were recorded during the total exposure time.

The measured HCP values of the steel rebar in the beams subjected to SACP did not attain protection potential levels. However, the galvanic couple Zn‐steel provided enough current for the protection of the steel. Visual inspection of concrete cores extracted from the beams indicated that corrosion products were not present at the steel‐concrete boundary. On the other hand, the ICCP applied to eight concrete beams provided excellent corrosion protection to the steel rebar.

This work revealed that the SACP system (thermally sprayed zinc) works well in high relative humidity environments and can be successfully used to protect steel reinforced concrete structures manufactured with calcareous aggregates which are endemic of the region and commonly used for infrastructure construction in the Yucatán peninsula.

This study aims to study the effect of Sn on the corrosion behavior of weathering steel (WS) in a simulated tropical marine atmosphere.

Indoor alternate immersion tests, electrochemical measurements and real-time current-monitoring technology based on the galvanic corrosion principle were used and the scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy and electron probe microanalyzer were used to analyze the morphology and component of the rust layer.

The results indicated that Sn has a positive influence on the corrosion process. Sn participated in the composition of the rust layer in the form of SnO₂ and is enriched in the inner rust layer. SnO₂ participated in the coprecipitation process with iron oxides and oxyhydroxides, which promoted further transformation of γ-FeOOH to α-FeOOH. As a result, the rust layer of Sn-containing steel was continuous, compact and effectively blocked the invasion of aggressive Cl⁻. Therefore, the additive of Sn enhanced the corrosion resistance of WS in a simulated tropical marine atmosphere.

The corrosion behaviors of WS were researched by the real-time current-monitoring technology which was rarely used.

The galvanic corrosion interactions of zinc and SS.304 have been studied in a tropical marine environment over a period of 427 days, under different area ratios. The galvanic interaction of zinc and SS.304 are highlighted in terms of the corrosion rate of zinc or SS.304 resulting from galvanic coupling, and the susceptibility of zinc to pitting due to galvanic corrosion. The galvanic potential and galvanic current of the system are monitored. The corrosion products at the interface of the bimetallic contacts are analysed with XRD technique and the pitting/grooving on zinc resulting from galvanic corrosion is measured using a high resolution microscope. The weathering parameters and environmental pollutants are monitored to give an insight into the possible means of favouring the galvanic interactions. The results of the study are discussed in the light of the above factors towards predicting a mechanism for the galvanic interactions of zinc and SS.304.

Diving has become a popular tourism activity for professionals and novices. Coral reefs or other types of natural sources are still the most preferred diving sites. However, they are under threat for many reasons, for example, climate change, intensive human activities or commercial use. Many countries have promoted artificial reefs to protect coral reefs and create new attractions for tourists. These new underwater atmospheres have changed diving and diving experiences. Wrecks, vessels, monuments, hotels, sunken cities or other types of artificial reef forms invite divers to discover and explore the human-driven underwater environment with novelty seeking, photographic opportunities and mysterious surroundings. This atmospheric turn has brought many advantages to communities, stakeholders and nations with socio-economic benefits, advantages in sustainability management and destination image. This chapter examines the range of underwater atmospheres in different structures and countries and explores their potential benefits.

This paper aims to investigate the corrosion behaviour of carbon steel in the Mauritian atmosphere over a three-year period. Atmospheric corrosion is a serious problem in Mauritius.

Carbon steel samples were exposed outdoors at various sites. Mass loss analysis was performed to determine the corrosion behaviour of the metal over the exposure period. Scanning electron microscopy and Raman tests were performed to investigate the formation of the corrosion products on the carbon steel surface.

It was found that the corrosion loss at two of the sites considered did not vary clearly according to the bilogarithmic law. Time of wetness was found to be a main factor affecting atmospheric corrosion in Mauritius. The corrosivity of the atmosphere was found to lie between categories C3 and C4, according to ISO 9223.

The results can be of essential help to the construction industry, especially as steel buildings are becoming very common in Mauritius. Moreover, as Mauritius is a tropical island, the results obtained can be useful in other tropical islands.

The complexity of atmospheric corrosion, further compounded by the effects of climate change, makes existing models inappropriate for corrosion prediction. The commonly used kinetic model and dose-response functions are restricted in their capacity to represent the non-linear behaviour of corrosion phenomena. The application of artificial intelligence (AI)-driven machine learning algorithms to corrosion data can better represent the corrosion mechanism by considering the dynamic behaviour due to changing climatic conditions. Effective use of materials, coating systems and maintenance strategies can then be made with such a corrosivity model. Accurate corrosion prediction will help to improve climate change resilience of the social, economic and energy infrastructure in line with the UN Sustainable Development Goals (SDGs) 7 (Affordable and Clean Energy), 9 (Industry, Innovation and Infrastructure) and 13 (Climate Action). This chapter discusses atmospheric corrosion prediction in relation to the SDGs and the influence of AI in overcoming the challenges.

This paper aims to reduce the cost, limit the time and increase raw material source availability, coral aggregate seawater concrete (CASC) composed of coral, coral sand, seawater and cement can be widely used for the construction of ports, levees, airports and roads to achieve practical engineering values. However, the naturally porous coral structure and abundant Cl⁻ in the seawater and coral lead to extremely severe reinforcement corrosion for CASC. It is well known that Cl⁻ is the main cause of reinforcement corrosion in the marine environment. Therefore, it is necessary to research the reinforcement corrosion of CASC in the marine environment.

In this study, linear polarization resistance was adopted to test the linear polarization curves of reinforcement in CASC with different exposure times. E_corr, R_p, I_corr and V_corr were calculated according to the weak electrochemical polarization theory and Stern–Geary formula. The effects of concrete cover thickness, exposure time, reinforcement types and inhibitor on reinforcement corrosion in CASC were analysed. The reinforcement corrosion degradation rule was determined, which provided theoretical support for the durability improvement, security assessment, service life prediction and service quality control of CASC structures in marine islands and reef engineering.

The corrosion resistance was enhanced with increased concrete cover thickness, and the concrete cover thickness for organic new coated steel should be at least 5.5 cm to reduce the reinforcement corrosion risks in CASC structures. The corrosion resistance of different types of reinforcements followed the rule: 2205 duplex stainless steel > 316 stainless steel > organic new coated steel > zinc-chromium coated steel > common steel. In the early exposure stage, the anti-corrosion effectiveness of the calcium nitrate inhibitor (CN) was superior to that for the amino alcohol inhibitor (AA). With the extension of exposure time, the decreasing rate of anticorrosion effectiveness of CN was higher than that of AA.

Reinforcement corrosion of CASC in a marine environment was studied. Concrete cover thickness, exposure time, reinforcement type and inhibitor influenced the reinforcement corrosion were investigated. New technique of reinforcement anti-corrosion in marine engineering was proposed. Possible applications of CASC in marine engineering structures were suggested.