Light expanded clay – material with variety of applications

Light expanded clay aggregate is a type of concrete made by heating clay to a high temperature in a rotary kiln. LECA is a natural building material of porous structure, light, non-flammable, resistant to humidity and chemical factors, and of very good thermal insulating properties. LECA has relatively low weight, which depending on the granulation is from 300 to 350 kg/m3. LECA concrete is a material of higher weight, on average 700 kg/m3.

LECA properties

Light expanded clay aggregate is fired from clayey rocks such as shales, clays and heavy clays. The material is light, odourless, chemically inert and resistant to fungi, mould, insects and rodents.

Among other LECA concrete properties, these are worth mentioning:

  • high fire resistance,
  • relatively low water absorption,
  • high resistance to pressing,
  • frost resistance,
  • good sound absorption,
  • easy mechanical treatment (e.g. cutting to length),
  • capacity to accumulate heat,
  • low thermal transmittance.

Advantages of using elements of LECA concrete

LECA concrete, thanks to the use of more porous LECA is a material of lower thickness than a regular concrete. Produced elements have usually the form of blocks and bricks, thanks to which they are lighter and work with them is easier. Taking into consideration these advantages, LECA concrete is used to produce wall and ceiling blocks, partitions, as well as various fittings necessary in building construction. Rough texture of walls made of LECA prefabricates significantly facilitates adhesion of plaster.

Disadvantages of LECA concrete

Because of slightly lower thickness in comparison with bricks or silicate blocks, walls of LECA concrete do not absorb noise that well. Moreover, given the way of construction with this material, once the works are over, it is necessary to remove so called technological humidity. Using LECA concrete may entangle the need to use more expensive thermal insulating mortars to keep correct thermal insulation of one-layer walls.

Prefabricated LECA concrete elements

As it was mentioned above, prefabricated LECA concrete elements are usually blocks or bricks. All of them have necessary openings (for pipes and other installations), allowing to save much time while building a house. LECA concrete can also be used to produce more refined semi-finished products, such as ‘L’ shuttering blocks and U-fittings which allow to prepare lintels.

The most popular applications of LECA concrete

LECA concrete is a versatile material used in construction sector. Its main applications are:

  • insulations of wooden and concrete ceilings and flat roofs,
  • floor insulations on the ground,
  • execution of drains (for example during construction of landfills),
  • filling channels with pipes and pipelines,
  • gardening.

In frame construction, LECA blocks can be used for both internal and external walls, regardless of number of storeys.

LECA concrete can also be used in geotechnical engineering, where it is used as a LECA filling which frequently eliminates expensive manners of ground strengthening (pilling, injection, ground replacement, special foundations). In road building, LECA is used a part of LECA-asphalt layer. It can also be used as a layer profiling surfaces, as well as a thermal insulating layer, special floor, thermal insulating in construction buildings.