Durability of marine concrete in libya field study on five seaports abdalla o. They are subject to corrosive agents which can corrode the reinforcing steel causing spalling, rusting, and shortening the service life of the structure. The prediction of deterioration in marine concrete structures is a major challenge that will still require much research input. Gilani 2 abstract the construction practice of marine concrete structures is of a great concern, considering the severe.
Rock, sand, concrete, and steel are some of the conventional materials used in marine applications. Damage to concrete structures with gypsumcontaminated aggregate occurs frequently. Deterioration of reinforced concrete in the marine. In marine environments, disintegration of concrete and corrosion of steel are the two main forms of deterioration. The following summary discusses potential causes of concrete deterioration and the factors that influence them. Self healing matrix formed by the bacteria excreates calcium components to heal concrete.
In order to delay the ingress of chlorides, such structures require the use of thick, dense concrete covers and strict crack width limitations. A wide range of marine concrete structure types has been presented in this chapter, covering the range of techniques that have been commonly used since the start of port and coastal construction in south africa and abroad. Feb 01, 2002 case studies of concrete deterioration in a marine environment in portugal case studies of concrete deterioration in a marine environment in portugal costa, antonio. Marine concrete structures have to withstand the extreme environmental pressure. While this is a positive change, often the quality and the rationale behind the testing are. Deterioration of concrete structures under marine conditions and their inspection and repair authors. While this is a positive change, often the quality and the rationale behind the testing are not sufficiently well defined. Properly designed concrete structures are both strong and durable. Oct 16, 2014 the present case sudy is about the upcoming marine structures and methods to deal with the deterioration of structures with the help of bacterial injection in concrete. Deterioration of concrete in marine structure ijir. Magnesium, sulfate, and chloride ions, and dissolved co2 present in sea water, act as agents of destruction for all the hydration. Climate resilient concrete structures in marine environment of bangladesh page 2 the views in this document are those of the authors and they do not necessarily reflect the views of the research for community access partnership recap, or cardno emerging markets uk ltd. Strategy for protection of marine concrete structures. Case studies of concrete deterioration in a marine environment in portugal article pdf available in cement and concrete composites 241.
Concrete exposed to seawater effects and preventions. Therefore, in this study, the effects of using different quantities of gypsumcontaminated aggregate on the expansion and compressive strength of concrete were investigated over a period of one year. A typical example is the prediction of combined transport and deterioration mechanisms in both cracked and uncracked concretes. Corrosion and deterioration of many concrete structures can be attributed to construction quality and design parameters. Chapter 5 environmental deterioration of concrete wit press. Pdf case studies of concrete deterioration in a marine. For example, this strategy may apply to structures of longer life than the intended service period by using concrete structures with reinforcing bars of anticorrosion steel for example, stainless steel or epoxycoated steel. These has been dealt with by chindaprasirt et al 4. However, concrete structures are vulnerable to a number of factors that can cause deterioration.
Deterioration process on marine concrete structures. The prediction of deterioration in marine concrete structures is a major challenge. Concrete can deteriorate for a variety of reasons, and concrete damage is often the result of a combination of factors. The deterioration of the system is commonly measured with respect to a physical parameter. This guideline entitled guidelines on strategic maintenance for port structures aims at providing developing countries, particularly asean countries, with assistance to appropriately maintain their various port structures such as concrete structures and steel structures. A similar effect is caused by alkali aggregate reaction whereby the presence of water in concrete permits a reaction between silica in certain aggregates and the alkalis in cement. A study on deterioration of reinforced cement concrete.
Over the past 20 years, corrosion testing on concrete structures has been used increasingly for monitoring deterioration as well as for defining the areas in need of repair. Environmental deterioration of materials witelibrary home of the transactions of the wessex institute, the wit electroniclibrary provides the international scientific community with immediate and permanent access to individual. Service life prediction of reinforced concrete structures. With regard to salt damage to concrete structures, simple methods for dealing with the complicated process of durability can be categorized as follows. Krystol internal membrane kim is a hydrophilic crystalline admixture used to create permanently waterproof concrete.
In marine environments, reinforcement corrosion is directly related to the chloride content in the concrete near the steel surface, which should not be greater than 0. Strategy for new marine structures preventive maintenance strategy 1. The deterioration of reinforced concrete structures not only depends on the microstructure of the concrete but also on severe exposure conditions in a particular environment. Walsh a dissertation submitted in partial fulfillment of the requirements for the degree of doctor of philosophy in civil engineering department of civil and environmental engineering college of engineering university of south florida major professor. The corrosion of steel reinforcement was first observed in marine structures and chemical manufacturing plants. The present case sudy is about the upcoming marine structures and methods to deal with the deterioration of structures with the help of bacterial injection in concrete. Mar 10, 2014 organisms play a significant role in the deterioration of concrete. Aggregates in much of the southern part of china are contaminated with gypsum.
Estimation method on deterioration of marine concrete. Design, durability and performance comprehensively examines structures located in, under, or in close proximity to the sea. Once the ph level of concrete falls to 910, the passive layer is disrupted leading to. The duracrete model has been tested in the field on six marine structures on the dutch coast, from which chloride profiles. Different materials such as concrete, stone, timber, and steel have been used for construction of marine structure. Timber, iron and steel and concrete immersed in sea water are exposed to the action of agencies producing damage and deterioration of structures in sea water skip to main content. A complex interplay of physical and chemical factors affects the performance of concrete in marine structures. Pdf the longterm behaviour of concrete structures has shown that their main cause of distress is reinforcement corrosion.
The best concrete reinforcement solution for marine structures. Investigations have shown that the principal cause of the deterioration was corrosion of reinforcing steel due to the presence of chlorides, with marine salts being the main source. Next prev concrete durability and repair technology. So far as marine structures are concerned, reinforcement concrete needs to be a highly durable and corrosion free structural material demanding little or no maintenance. Although, corrosion of steel reinforcement has been acknowledged as the principal cause of deterioration of marine concrete structures, disintegration of concrete usually accelerate the process of steel corrosion. Cases of comparatively rapid deterioration have usually resulted from failure to consider and. Recent experimental developments have provided a better understanding as to how biological and physicochemical processes associated with mid affects the longterm durability and mechanical properties of concrete structures. In coastal areas where corrosion is imminent for the construction of marine structures like platform, quay walls, watchtowers and. Because of concretes inherent protection, reinforcing steel does not corrode in the majority of concrete elements and structures. Corrosion of steel in submerged concrete structures. A study on deterioration of reinforced cement concrete structures in mumbai. Types of marine structures construction details and uses.
Concrete has had extensive use as construction material for seawalls, jetties, groins, breakwaters, bulkheads, and other structures exposed to sea water. When critical concentration of free cl accumulates. Because not only japan but also many countries are plagued by aged. Concrete, marine environment, chloride, blast furnace slag cement, reinforcement corrosion, service life, probabilistic model 1 introduction durability of concrete structures in marine environment has been an issue for many decades, due to the perception of sea water as aggressive to concrete and reinforcement and the long. Where mass concrete is relatively free to expand in all. Most present design codes do not give quantified guidance for. Case studies of concrete deterioration in a marine environment in portugal. Corrosion of steel in submerged concrete structures by michael t.
There are enough evidences to show that a wide variety of organisms can cause concrete deterioration table 1. Strategy for protection of marine concrete structures against. Nevertheless, from the time it is formed in the tree, wood is subject to deterioration by a variety of agents. The primary purpose of waterproofing concrete marine structures is the protection of reinforc. Estimation method on deterioration of marine concrete structures. Durability of marine concrete in libya field study on five seaports xii dbmc, porto, portugal, 2011 3. Climate resilient concrete structures in marine environment of bangladesh page 2 the views in this document are those of the authors and they do not necessarily reflect the views of the research for community access partnership recap, or cardno emerging markets uk ltd for whom the document was prepared. In its natural state, with a ph level of around 12 concrete provides a good measure of protection to embedded reinforcement.
Structural deterioration an overview sciencedirect topics. The three main causes of deterioration in concrete marine structures are. These factors lead to rapid deterioration of concrete and a drastically shortened lifespan. The coastal and offshore structures are always in contact with seawater and there are number of physical and chemical deterioration processes takes place. Guideline for service life design of structural concrete. These structures need to be designed in such a way that can withstand various loads for example service loads, loads from ships, and loads generated by the impact of sea waves. Marine concrete structure an overview sciencedirect topics. Climate resilient concrete structures in marine environment.
Concrete specification and maintenance strategy for marine. Deterioration of concrete structures under marine conditions and their inspection and repair. Guide for design concrete marine structures aci 357. For aircraft hangers, reinforced concrete shells comprising of thin circular slabs and deep edge beams provide an economical solution. Materials and methods for corrosion control of reinforced. Methods that entail estimating concrete deterioration from weather factors in the marine environment 2 by grasping the movement of chloride ions into the concrete 3. Predictions of reinforced concrete durability in the marine environment.
Pdf a study on deterioration of reinforced cement concrete. Aalborg universitet deterioration of concrete structures. One of the most aggressive exposure conditions for concrete is the marine. Durability of marine concrete in libya field study on five. Deterioration of concrete structures under marine conditions and their inspection and repair open pdf. Durability of concrete structures an introduction pdf. Deterioration can result in loss of strength and unsafe conditions. Repair terminology causes of concrete deterioration. Strategies for protection of marine concrete against chloride attack while this paper focus on the additional protection measures, the two most important aspects of achieving design life of concrete structures are suitable concrete quality and adequate cover. Case studies of concrete deterioration in a marine. The deterioration of reinforced concrete structures is a major problem. This paper describes the deterioration of reinforced concrete structures at a liquefied gassulfur plant that occurred shortly after completion of the construction.
Concrete deterioration reinforced concrete is a very versatile construction material. The action of microorganisms on concrete structures can be classified according to their effects on concrete surfaces, concrete matrices, and on cracking and crack growth amann et al. Specifications for marine structures in hk durability and design life of marine concrete structures factors affecting durability of marine structures conventional specifications for marine concrete durability performance of conventional marine concrete structures development of marine concrete specification durability performance of marine concrete. A major emphasis of the book is on the longterm performance of marine concrete structures that not only represent major infrastructure investment and provision, but are also required to operate with minimal maintenance. If you look at the deterioration of concrete as one of the important event, which is. To make the students to gain the knowledge on quality of concrete, durability aspects, causes of deterioration, assessment of distressed structures, repairing of structures and demolition procedures.
Deterioration of concrete structures thoftchristensen, palle publication date. Without the passive film, the steel would corrode at rates at least 1,000 times higher aci 222 2001. The concrete structures built in marine conditions are always exposed to seawater either directly or indirectly. Deterioration of concrete in the marine environment request pdf. Corrosion of reinforcement is the main cause of deterioration of rc structures located in marine environments or subjected to deicing salts. In this paper, the service life of structures exposed to aggressive environments is measured by the probability of cracking and spalling of concrete cover. It is evident that concrete has become an indispensable component of marine structures, ensuring durability and. Deterioration process on marine concrete structures penetration of chloride into concrete penetration of clvia pores to the interior of concrete cement hydrate binds some of clchemically fredels salt c 3a.
Guideline for service life design of structural concrete a. Concrete specification and maintenance strategy for marine structures ir peter leung honorary advisor to standing committee on concrete technology. Welcome to the lecture 4 on module 3 of ocean structures and materials, a virtual classroom under the. The steel forms a passive layer which serves to protect it against corrosion. Corrosion of reinforcing steel and other embedded metals is the. Concrete in marine environments concrete construction. Durability of marine concrete in libya field study on. Deterioration process on marine concrete structures marine environment chloride penetration into concrete passive film on reinforcement is lost reduction of crosssection of reinforcement corrosion of reinforcement starts degradation of structural performance of the structure introduce of corrosion cracking and spalling of concrete water oxygen. Guidelines on strategic maintenance for port structures. These 10year exposure tests have shown that the deterioration of reinforced concrete is influenced by characteristics of the concrete as well as the marine environment. Unit i maintenance and repair strategies 9 maintenance, repair and rehabilitation, facets of maintenance, importance of. Corrosion of reinforcing steel is the most common cause of concrete. Without correct mixing, design, placement, and curing, the durability of concrete can be impaired.
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