- Project plans
- Project activities
- Legislation and standards
- Industry context
- Specialist wikis
Last edited 15 Nov 2020
Bentonite is a naturally-occurring material created by the alteration of volcanic ash in marine environments. It consists mainly of the clay mineral smectite, usually montmorillonite, which occur as layers which are compressed between other rock types.
Bentonite is usually obtained by quarrying, with a solid extracted form with a typical moisture content of around 30%. This moisture content is reduced to approximately 15% by air and/or forced drying after being crushed. Once this has been done, bentonite is either sieved in a granular form, or milled into powder form.
In civil engineering, bentonite is used as a thixotropic, support and lubricant agent. Typical applications for this agent include the construction of diaphragm walls, foundations, pipe jacking, tunnelling, and so on. Its viscosity and plasticity also make it suitable for use in Portland cement and mortars.
Bentonite’s thixotropic properties mean it forms a highly water-resistant gel which, when mixed with additives, can create a permanent barrier to water flow. This is commonly used in situations where soil particles are too small for cement grouting to be suitable, typically to combat seepage in alluvial soils beneath the foundations of dams or other water-bound structures.
 Find out more
 Related articles on Designing Buildings Wiki
Featured articles and news
Take just two minutes to provide your feedback.
An update of standards and regulations are under consideration.
Exploring the key to the adoption of this abundant energy source.
His clients have ranged from Liberace to St Nick to world-class athletes.
These tactical structures can be permanent or temporary.
Organisation recognises milestones of the project's next phase.
Welding and metalworking businesses must manage respiratory risks.
New report explores how regulations are being put into action.
The golden thread and BS 8644-1.
Bitumen binder may delay road surface deterioration.
A varied portfolio of internationally recognised buildings.
Threatened by housing and expanding universities.
Getting "boots on the ground" to make things happen.
Building systems may begin to learn.