Lecture

Adjusting LC³ Cement Composition

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Description

This lecture covers the impact of sulphates in LC³ cement, the role of sulphates in Portland cement, the importance of sulphation in cements with calcined clays, and the effects of alumina content and alkalis on early strength and reactivity. It also discusses the alkali silica reaction, the use of alumina silicate supplementary cementitious materials to prevent ASR, and the influence of kaolinite content on alumina reserves. The presentation concludes with a summary emphasizing the need for sulfate level adjustments and proper alkalis balance in LC³ systems to enhance reactivity and control ASR effectively.

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 (29)

Sulfate

The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid. "Sulfate" is the spelling recommended by IUPAC, but "sulphate" was traditionally used in British English. The sulfate anion consists of a central sulfur atom surrounded by four equivalent oxygen atoms in a tetrahedral arrangement.

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.

Alkali–silica reaction

The alkali–silica reaction (ASR), more commonly known as concrete cancer, is a deleterious swelling reaction that occurs over time in concrete between the highly alkaline cement paste and the reactive amorphous (i.e., non-crystalline) silica found in many common aggregates, given sufficient moisture. This deleterious chemical reaction causes the expansion of the altered aggregate by the formation of a soluble and viscous gel of sodium silicate (Na2SiO3, also noted Na2H2SiO4, or N-S-H (sodium silicate hydrate), depending on the adopted convention).

Alkali metal

The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties. Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour.

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