Metakaolin Range Pozzolanic additives for concrete, GFRC, lime mortar and plaster
Imerys metakaolin ranges such as our Argical™ M and MetaStar™ series provide a broad range of benefits in concretes, lime mortars and plasters.
Imerys metakaolin is manufactured through the calcination of high purity kaolin to form an amorphous pozzolanic white mineral additive for use in concrete and cement based products. The pozzolanic reactivity of metakaolin refers to its ability to react with calcium hydroxide in cement based products. Metakaolin is also used as an additive to substitute cement in concrete, renders and mortars.
Imerys metakaolin provide:
- Reduced Efflorescence
Metakaolin reduces efflorescence by reducing the porosity of the concrete and reacting with lime salts before they reach the concrete surface.
- Protects Reinforcement bar
Metakaolin reduces the porosity of concrete which prevents corrosive salts and ions from attacking reinforcing metal bars. It is ideal for road and marine structures exposed to corrosive salts.
- Higher compressive strength
Where high strength concrete is required, metakaolin increases cured compressive strength of concrete and speeds up curing and early strength development, making it ideal for applications where high strength is required quickly such as airport runways.
Metakaolin can also be used to modify the handling properties of wet concrete, particularly benefiting the viscosity profile and reducing the tendency to bleed, making leveling and achieving a good surface finish easier.
Metakaolin in Glass Fiber Reinforced Concrete (GFRC)
GFRC is a combination of mineral components and glass fiber, obtained by a projection method. Glass fiber strengthens concrete properties and gives GFRC cohesion, flexural resistance and ductility.
Normally with time, lime formation within the cement, leads to weaker connections between the cement matrix and the fibers that can no longer slip. The material becomes unable to absorb the energy and finally leads to a fatal brittle breakdown of the area (loss of ductility).
Combining lime with metakaolin provides calcium silicate hydrates (CSH), which improve the mechanical performance and durability of concrete and, by consuming lime, prevent it spoiling the glass fiber.
Lime mortars and plasters
Imerys reactive metakaolin pozzolans are ideal for achieving hydraulic set in traditional lime putty mortars and plasters and for improving the mechanical strength of floor mortars. Pozzolans are particularly helpful when applying lime putty mixes in damp, frost prone or exposed locations.
The addition of metakaolin pozzolans to lime putty mixes increases compressive strength which helps to offer additional protection during the carbonation period.
We recommend the following grades:
- Argical™-M 1000
- Argical™-M 1200S
- MK 40
- MetaStar™ 501
We offer a full range of custom formulation and technical and process support services to help you match the right mineral grade to your application requirement.