Carbonation and Corrosion

Carbonation and Corrosion

Carbonation is the term used to describe the effect of carbon dioxide on a material. The phenomenon rarely leads to structural problems but carbonation-induced corrosion can lead to unsightly spalling on structures. The repair costs, for example to multi-storey office development façades, can be considerable. Carbonation of cementitious materials results in a lowering of the …

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Chloride Ingress into Concrete

For concrete structures in chloride-containing environments, the ingress of chlorides can take place in different ways. Through uncracked concrete, the ingress mainly takes place by capillary absorption and diffusion. When a relatively dry concrete is exposed to saltwater, the concrete may suck the saltwater relatively fast, and intermittent wetting and drying may successively accumulate high …

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Alkali–Aggregate Reactions

Alkali–Aggregate Reactions

In this article, the three types of Alkali–Aggregate Reactions are described: (1) alkali–carbonate reaction (ACR), (2) alkali–silicate reaction, and (3) alkali–silica reaction (ASR). Alkali–Aggregate Reactions Water in the pores of hardened concrete contains quantities of dissolved ions largely deriving from the cement matrix. In mature concrete, the vast majority of dissolved cations are those of the alkali …

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Concrete Distress Identification

Concrete Distress Identification

Distress Identification Before attempting any repair procedure it is necessary to have a planned approach to investigate the condition of concrete and reinforcement. While the diagnosis of damage or deterioration in some cases is reasonably straightforward, it may not be so in many cases. Particularly difficult are cases in which the cause and effect phenomenon …

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Visual Defects of Concrete

concrete deterioration

Visual Defects of Concrete: one of the simplest ways to understand what exactly causes concrete to fail would be performing a Visual Survey of the deteriorated concrete structure. When a client hires an Engineer to inspect a concrete structure, it is most likely because the owner visually noted some form of deterioration. This, technically, may be considered a …

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Surface Rust Stains and Efflorescence

concrete deterioration

In this article, two of the visual defects that might appear on concrete are discussed: Surface Rust Stains and Efflorescence (or Leaching) of concrete. Surface Rust Stains Rust stains are caused by corroded steel below the surface which has inadequate cover, or by corroded steel that is fully exposed due to a spall or poor …

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Cracking and Honeycombing of Concrete

concrete deterioration

In this article, two of the visual defects that might appear on concrete are discussed: Cracking and Honeycombing of concrete. Cracking of Concrete Cracking is frequently occur in concrete structures. There are various types of cracking that may occur. Cracks are caused by numerous diverse reasons and can be detected by a Visual Analysis. It should be …

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Surface Scaling and Spalling of Concrete

concrete deterioration

In this article, two of the visual defects that might appear on concrete are discussed: Surface Scaling and Spalling of concrete. Surface Scaling of Concrete Scaling is a form of disintegration and is due in most part to freeze–thaw reactions which cause the concrete to flake or peel off at the exposed surface. Scaling is indicative of …

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