Lecture

Hydration 2: C-S-H

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Description

This lecture delves into the hydration process of calcium silicates, focusing on C3S and C₂S. It covers the formation of calcium hydroxide, portlandite, and calcium silicate hydrate (C-S-H), which constitutes a significant portion of the hydrated paste. The lecture explores the structure of C-S-H, including its variable calcium to silicate ratio and ways to modify it. It discusses the substitution of silicon by aluminum in C-S-H and the experimental evidence supporting its structure. The lecture also presents different models describing the atomic, meso, and microstructure of C-S-H, shedding light on its complex nature in cementitious materials.

In MOOC

Cement Chemistry and Sustainable Cementitious Materials

We all know the concrete used to build our houses, offices, schools, or bridges, but do you know why concrete resists? The aim of this course is to offer solid knowledge on cement chemistry to practioners or to new student in the field. It is therefore not necessary to have a cement background, however basic concepts in chemistry, physics and crystallography can help. This course lasts 6 weeks during which you can take theoretical courses and tutorials to test the cement in the laboratory. You will learn h

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Related concepts (16)

Energetically modified cement

Energetically modified cements (EMCs) are a class of cements made from pozzolans (e.g. fly ash, volcanic ash, pozzolana), silica sand, blast furnace slag, or Portland cement (or blends of these ingredients). The term "energetically modified" arises by virtue of the mechanochemistry process applied to the raw material, more accurately classified as "high energy ball milling" (HEBM). This causes, amongst others, a thermodynamic transformation in the material to increase its chemical reactivity.

Cement

A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.

Portland cement

Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum. Several types of portland cement are available.

Silicate

In chemistry, a silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula [SiO4−x(4-2x)− ]n, where 0 ≤ x < 2. The family includes orthosilicate (x = 0), metasilicate (x = 1), and pyrosilicate (x = 0.5, n = 2). The name is also used for any salt of such anions, such as sodium metasilicate; or any ester containing the corresponding chemical group, such as tetramethyl orthosilicate.

Calcium oxide

Calcium oxide (formula: CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature. The broadly used term lime connotes calcium-containing inorganic compounds, in which carbonates, oxides, and hydroxides of calcium, silicon, magnesium, aluminium, and iron predominate. By contrast, quicklime specifically applies to the single compound calcium oxide. Calcium oxide that survives processing without reacting in building products, such as cement, is called free lime.

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