Resistance of Concretes to External Chlorides in the Presence and Absence of Sulphates: A Review

Abstract

Corrosion of steel reinforcement due to chloride attack remains a major reinforced concrete durability concern. The problem is prevalent for concrete structures located within marine environments or frost-prone locations where chlorides containing de-icing salts are used. This paper is a state-of-the-art review into chloride binding in Portland cement concrete, with consideration of the differences induced by the presence of sulphates, such as found in seawater. The review also considers the use of supplementary cementitious materials (SCMs), the use of which has increased because of their potential to enhance durability and reduce the carbon footprint of concrete production. Such materials impact on phase assemblage and microstructure, affecting chloride binding and transport properties. Therefore, field and laboratory studies are critically reviewed to understand how these could help in the design of more durable concretes. The contributions of chloride binding, hydrate compositions and microstructures of the binding materials affecting chloride transport in concretes are also evaluated to suggest a more robust approach for controlling the problem of chloride attack.

Effect of Graphene Oxide Nanomaterials on the Durability of Concrete: A Review on Mechanisms, Provisions, Challenges, and Future Prospects

“…Concrete is vulnerable to a wide range of deterioration mechanisms, both physically and chemically, but chemical deterioration leads to an accelerated reduction in service life and is considered the most challenging. The chemical deterioration of concrete can occur due to various factors and the ingress of harmful agents such as sulphate ions (SO 4 2− ), carbon dioxide (CO 2 ), and chloride ions (Cl − ), which are considered the most significant and common deterioration agents of concrete [40,41]. Additionally, there are other factors that can lead to the deterioration of concrete, including calcium leaching, alkali-silica reaction (ASR), freeze-and-thaw cycles, and bacterial attacks [3,5,16,[42][43][44].…”

The Influence of Recipe-Technological Factors on the Resistance to Chloride Attack of Variotropic and Conventional Concrete

“…In the process of wetting, dry concrete absorbs a salty environment; then, in the process of drying, water evaporates from the mouths of the pores, and the salts remain in the concrete. So, as a result of alternating wetting and drying of concrete, there is a diffuse transfer of salts into the depths of the concrete body [4,15,28,48]. According to the results of testing concretes of the control composition, it was found that centrifuged and vibro-centrifuged concretes have a higher resistance to cyclic chloride attack compared to vibrated concrete.…”

“…The denser structure of the outer layer of centrifuged and vibro-centrifuged concretes with closed microporosity better resists a chloride attack. of concrete, there is a diffuse transfer of salts into the depths of the concrete body [4,15,28,48]. According to the results of testing concretes of the control composition, it was found that centrifuged and vibro-centrifuged concretes have a higher resistance to cyclic chloride attack compared to vibrated concrete.…”

“…Given that the issue of durability is directly related to the aggressiveness of environmental conditions, including water, the most important aspect of structural materials will be their resistance to various aggressive influences [4][5][6].…”