Lecture

Kinetics: the Induction period

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Description

This lecture by Professor Karen Scrivener explores the kinetics of the induction period in cement chemistry, focusing on the underlying mechanisms, heat evolution, and the three distinct periods: induction, acceleration, and deceleration. Different theories regarding the induction period, such as the protective membrane layer and nucleation theory, are discussed. The study delves into dissolution as negative growth, the effect of annealing on alite, and the evolution of dissolution rate. The lecture concludes with a summary highlighting the absence of evidence for a protective layer and the effectiveness of dissolution as a function of undersaturation, supported by geochemistry.

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 (32)

Solvation

Solvation describes the interaction of a solvent with dissolved molecules. Both ionized and uncharged molecules interact strongly with a solvent, and the strength and nature of this interaction influence many properties of the solute, including solubility, reactivity, and color, as well as influencing the properties of the solvent such as its viscosity and density. If the attractive forces between the solvent and solute particles are greater than the attractive forces holding the solute particles together, the solvent particles pull the solute particles apart and surround them.

Solubility

In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at the solubility equilibrium.

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.

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.

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