Concrete Glossary of Terms

Bleeding	The loss of water from freshly mixed concrete. 'Bleed Water' accumulates on the surface of the concrete. This is excess mixing water pushed out as a result of the consolidation and settlement of freshly laid concrete.
Brush Finish	A slip-resistant surface created by brushing the top of the concrete before it has thoroughly hardened.
Consistency	The condition of wet concrete that relates to its cohesion, flow or wetness. Consistency is measured by a slump test.
Curing	The process of ensuring that freshly poured concrete is protected and kept in a moist condition while hydrating in order to ensure durability and surface finish and to promote the maximum strength development.
Crazing	A concrete surface which has the appearance of a spiders web. This is an aesthetic problem. Some causes could be: wetting the surface during finishing, over finishing, or the top surface could have dried out too quickly whilst the body of the concrete was still moist.
Delaminating	A defect where the hardened surface layer of the concrete becomes separated from the main body of the concrete.
Durability	The ability of hardened concrete to resist the deterioration caused by weathering.
Dusting	This is the powdering of the surface of the concrete slab. It indicates that the wearing surface is weak.
Expansion Joints	These joints permit horizontal and vertical movement at adjoining parts of the structure.
Fibre	A synthetic material added to the concrete as an alternative method of secondary reinforcement. The material is usually made of nylon or polypropylene. It also helps reduce shrinkage cracks in early placement of concrete and improves impact resistance.
Finishing	Manual or mechanical process carried out on the surface of the compacted concrete to achieve the surface texture, appearance and serviceability.
Floating	The process done to concrete after it has been laid. Floating entails going over the concrete surface with a float. It smoothes the surface while opening the pores to allow proper bleed water to come to the surface.
Formwork	The material used to contain fresh concrete so as to maintain its shape and form during the setting process.
Fresh Concrete	Concrete that possesses enough of its original workability so that it can be placed and consolidated by the laying methods.
Hydration	The chemical reaction on mixing between cement and water, resulting in the hardening of concrete.
Screeding	The process of striking off excess concrete to bring the top surface of a slab to the correct grade and level.
Segregation	The separation of the constituents of the concrete, mainly coarse aggregate from the main body of the concrete, causing a lack of uniformity in their distribution.
Slump	The measure of the consistency and flowability of concrete.
Workability	That property of freshly mixed concrete that determines the ease with which it can be mixed, placed, consolidated and finished.
Working Life	The length of time between the mixing of the concrete and the start of stiffening.