Cement

Introduction
Applications of cement
History of cement
Raw materials
- Composition
- Extraction and processing
Manufacture of cement
- Crushing and grinding
- Blending
- Burning
- Grinding
The major cements: composition and properties
- Portland cement
  - Chemical composition
  - Hydration
  - Structural properties
  - Types of portland cement
- Slag cements
- High-alumina cement
- Expanding and nonshrinking cements
- Gypsum plasters
Cement testing
- Fineness
- Soundness
- Setting time
- Strength

References & Edit History Related Topics

Images

Concrete is being poured from a cement truck into a trench with rebar at the bottom, as workers guide the flow for a house foundation.

Eddystone Lighthouse: Sir James N. Douglass's version

At a Glance

cement summary

Related Questions

About what share of global carbon dioxide emissions comes from cement manufacturing?
How are cement and concrete used in roads and road bases?
How are cement raw materials blended to achieve the correct chemical composition?
How are limestone and other hard raw materials extracted for cement production?
How are soft raw materials such as chalk and clay extracted for cement production?
How can blast-furnace slag be used as a raw material for cement?
How can chalk and shell deposits be used in cement manufacturing?
How could reducing the amount of clinker in cement help lower emissions?
How could renewable energy and carbon capture reduce emissions from cement plants?
How did Isaac Charles Johnson contribute to the development of portland cement?
How did John Smeaton improve hydraulic lime for the Eddystone Lighthouse in 1756?
How did ancient Greek and Roman builders make hydraulic cement?
How did cement manufacturing spread beyond England during the 19th and 20th centuries?
How do air-entraining agents help concrete resist freeze-thaw damage?
How do bag filters and electrostatic precipitators reduce dust from cement plants?
How do calcium silicates react with water during cement hydration?
How do low temperatures affect freshly poured concrete?
How do masonry cements differ from ordinary portland cement?
How do pozzolanic materials such as fly ash form cementitious compounds with lime?
How do slag cements differ in composition from portland cement?
How does a rotary kiln turn raw cement materials into clinker?
How does calcium chloride help concrete set in moderately cold weather?
How does cement act as a binding material in concrete?
How does hydrophobic cement resist deterioration during storage?
How does mortar differ from concrete?
How does prestressed concrete resist forces that would crack ordinary concrete?
How does pretensioning differ from posttensioning in prestressed concrete?
How does reinforcing steel improve the strength of reinforced concrete?
How does sulfate-resistant portland cement protect concrete from chemical attack?
How does the semidry process of cement manufacturing work?
How does the water-to-cement ratio affect concrete strength?
How does the wet process of cement manufacturing differ from the dry process?
How hot does the firing end of a cement rotary kiln become?
How is cement clinker cooled after it leaves a rotary kiln?
How is concrete cured after it is poured?
How is gypsum used during the final grinding of cement clinker?
What are the five standardized types of portland cement in the United States?
What are the four main stages of portland cement manufacturing?
Where does the word “cement” come from?
Which factory-made building products can be produced using portland cement?
Which four main compounds make up portland cement?
Which impurities must be limited in raw materials for portland cement?
Which ingredients are mixed to make ordinary concrete?
Which raw materials provide silica and alumina for portland cement?
Which type of portland cement develops high early strength?
Who patented the process for portland cement in 1824?
Why are heat exchangers used in cement kilns?
Why are limestone and clay commonly used to make portland cement?
Why are low-alkali cements used with certain aggregates?
Why are oil-well cements designed to set slowly at high temperatures and pressures?
Why can concrete lose strength if it dries too quickly?
Why can prestressed concrete be used to build long bridges and wide roofs?
Why can too little water make concrete difficult to pour and spread?
Why can too much water make concrete weaker?
Why did Joseph Aspdin call his product portland cement?
Why do high-slag cements have greater resistance to chemical attack?
Why does cement manufacturing produce carbon dioxide emissions?
Why does filtering slurry before it enters a cement kiln reduce fuel use?
Why is concrete used for dams and other large construction projects?
Why is kaolin used to make white portland cement?
Why is low-heat portland cement useful in large concrete structures?
Why must the magnesia content of portland cement be kept low?

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External Websites

National Center for Biotechnology Information - PubMed Central - Cement selection criteria for full coverage restorations: A comprehensive review of literature
Massachusetts Institute of Technology - MIT News - Explained: Cement vs. concrete Â— their differences, and opportunities for sustainability
PennState College of Engineering - Composition of cement
University of Babylon - Chemical Composition of Cement (PDF)
The Spruce - The Difference Between Cement, Concrete, and Mortar

Britannica Websites

Articles from Britannica Encyclopedias for elementary and high school students.

cement - Children's Encyclopedia (Ages 8-11)
cement - Student Encyclopedia (Ages 11 and up)

Cement

building material

Written by

Thomas O. Mason

Professor of Materials Science and Engineering, Northwestern University, Evanston, Illinois. Coeditor of Symposium on Point Defects and Related Properties of Ceramics and others.

Thomas O. MasonAll

Fact-checked by

Britannica Editors

Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....

Britannica Editors

Last updated

Nov. 7, 2026 •History

Cement, in general, adhesive substances of all kinds, but, in a narrower sense, the binding materials used in building and civil engineering construction. Cements of this kind are finely ground powders that, when mixed with water, set to a hard mass. Setting and hardening result from hydration, which is a chemical combination of the cement compounds with water that yields submicroscopic crystals or a gel-like material with a high surface area. Because of their hydrating...

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