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Concrete degradation may have many different causes. Concrete is mostly damaged by the corrosion of reinforcement bars due to the carbonatation of hardened cement paste or chloride attack under wet conditions. Chemical damage is caused by the formation of expansive products produced by chemical reactions (from carbonatation, chlorides, sulfates ...
A cement is a binder, whereas concrete is the composite material resulting from the mixing and hardening of cement with water (or an alkaline solution in the case of geopolymer cement), and stone aggregates. Materials of both types (geopolymer cements and geopolymer concretes) are commercially available in various markets internationally.
Cementation (geology) A brief, easy-to-understand description of cementation is that minerals bond grains of sediment together by growing around them. This process is called cementation and is a part of the rock cycle. Cementation involves ions carried in groundwater chemically precipitating to form new crystalline material between sedimentary ...
Calcium aluminates can form complex salts in combination with different types of anions.Two series of calcium aluminates are known in cement chemistry: AFm and AFt phases, being respectively mono- or tri-substituted with a given divalent anion X (e.g. SO 2− 4, CO 2− 3, or hosting a divalent impurity such as SeO 2− 4 [3]...), or with two units of a monovalent anion, e.g. OH −, Cl − ...
Argon oxygen decarburization. Argonoxygen decarburization (AOD) is a process primarily used in stainless steel making and other high grade alloys with oxidizable elements such as chromium and aluminium. After initial melting the metal is then transferred to an AOD vessel where it will be subjected to three steps of refining; decarburization ...
Sulfate attack in concrete and mortar. Cement hydration and strength development mainly depend on two silicate phases: tricalcium silicate (C 3 S) (alite), and dicalcium silicate (C 2 S) (belite). [ 1 ] Upon hydration, the main reaction products are calcium silicate hydrates (C-S-H) and calcium hydroxide Ca (OH) 2, written as CH in the cement ...
The cement is made by fusing together a mixture of a calcium-bearing material (normally calcium oxide from limestone) and an aluminium-bearing material (normally bauxite for general purposes, or refined alumina for white and refractory cements). The melting of the mixture is achieved at 1600 °C and is energy demanding.
Calcium oxide is a crucial ingredient in modern cement, and is also used as a chemical flux in smelting. Industrial calcination generally emits carbon dioxide (CO 2 ). A calciner is a steel cylinder that rotates inside a heated furnace and performs indirect high-temperature processing (550–1150 °C, or 1000–2100 °F) within a controlled ...