Lime uses

Construction

Iron and steel

The use of lime in iron and steelmaking is discussed in our Manufacturing section.

Building construction

The construction and building industry are a major user of lime products.
Lime currently plays an important part in the following areas:

• As a component of mortars, exterior rendering and interior plasters
• As a binder in the production of aerated concrete blocks, silica bricks, and fire resistant board
• In lime concrete, lime wash and conservation/heritage uses

Mortars, renders, and plasters

Mortar is essential in masonry and brickwork, working together with the bricks and blocks to form stable and durable structures.

External rendering and internal plastering are used to cover up differences in level, to provide a protective layer that is suitable for the final decorative finish.

Incorporating lime into mortars, renders and plasters benefits the fresh and hardened properties of the materials and associated construction. More information on lime containing mortars is available in our Technical section and through the European Lime Association. General information and guidance on mortars is available from MPA Mortars.

Autoclaved aerated concrete blocks

Lime is mixed with cement, sand, water and aluminium powder to give a slurry which rises and sets to form honeycomb, lightweight, structural blocks which have excellent thermal and sound insulation properties – these are widely used throughout the building industry.

Information on the uses of aerated concrete blocks is available from the Aircrete Products Association.

Sand-lime bricks

Made entirely of sand, lime and water, the raw sand-lime brick mixture is matured in reactors before it is compressed under vapour pressure to form sand-lime bricks. During the process of pressure-hardening in autoclaves, the large proportion of available calcium oxide ensures that optimum calcium silicate hydrate crystals are formed to give the brick its high mechanical strength, density and stability.

Lime concrete

Lime concrete or "limecrete" is made by mixing controlled amounts of sand, aggregate, binder and water. Hydraulic lime or hydrated lime with additives are used as the concrete binder. This type of concrete is widely used in heritage and conservation construction and is increasingly popular in ‘eco’-buildings – for example – with underfloor heating systems.

Limewash

Limewash is a traditional method of painting walls with a colour base that allows the masonry to breathe, providing both protection and aesthetic appeal.

Limewash is also widely used in agricultural buildings due to its germicidal qualities coupled with its extreme ease of application and low cost.

Conservation / heritage

Nearly all masonry up to the early 20th century was constructed using mortars where lime was the only binder in the mortar. Renders and plasters were also made in this way. Most masonry construction was of solid walls and the use of lime binders allowed the moisture to quite freely move within the structure. It is important that mortars used in repair and renovation of these buildings are sympathetic and compatible with the other materials in the structure, are able to accommodate minor movements and to allow water vapour to escape and not trap moisture within the structure.
The restoration of these buildings is often important for surrounding communities, providing them with lasting historical and cultural heritage, prolonging the buildings use, and often even increasing the aesthetic appeal of the local area. More information is available in our Technical section.

Civil Engineering

• Infrastructure projects benefit from the use of lime materials, making the best use of onsite materials and acting as a modifier to extend the service life of others.
• Lime currently plays an important part in the following areas:
• In the drying, improvement and stabilisation of soils to provide a platform for heavy construction
• As a multi-functional additive in the production of asphalt for road construction

Soil stabilisation

Lime stabilisation reduces the need to bring in aggregates and other materials to site and avoids removal of unmodified materials thereby significantly reducing transport costs and environmental impact.

Although widely known as soil stabilisation, there are a number of distinct processes which can be carried out by the addition of lime to soft existing soils. Improvement is the first process step, where the heat generated by the reaction of the moisture in the soil with the lime reduces the moisture content. This is followed by modification, where the soil consistency changes through the reaction of the clay particles with lime. Over time, the soil becomes stabilised by long term chemical reactions that increase the soil strength. Using this process, it is possible to convert an unworkable site into a solid working platform providing a base for construction development or as the base layers for pavements, and foundations to earthworks. More information on the use of lime in soil stabilisation is provided in our Technical section. General information and guidance on soil stabilisation is available from Britpave.

Asphalt

Lime is used as a multi-functional additive to asphalt used for road and pavement construction. Lime is a beneficial addition to asphalt as it improves durability – providing up to 25% longer life; increasing moisture resistance; and increasing ageing resistance.

Asphalt is currently used to surface 95% of UK roads, as well as for playgrounds, vehicle parking areas, distribution centres, airport runways and pavements.

More information on the use of lime in asphalt is provided in our Technical section. General information and guidance on asphalt is available from MPA Asphalt