The density of concrete

The density of concrete is an important factor already in the planning of concrete components. In addition, concrete types are also differentiated according to the respective concrete bulk density. But the concrete density also has an influence on the longevity of the building material.

Calculation of the density in general

The relationship between the volume and mass of a body defines its density. From this a simple calculation formula can be derived: v x m = p (volume times mass equals density). However, it is not so easy with concrete because the composite construction material consists of different materials:

  • cement
  • water
  • Surcharge (sand, gravel, gravel)
  • Concrete admixtures
  • concrete additives

The density of concrete is adjusted by the respective surcharge

The gravel and gravel types used vary from conventional gravel to open-pored pumice stone. Therefore, the concrete density (proh) is an important factor. The pipe density in the dry state, including the dry bulk density, detects the density as volume density or geometric density, ie in their actual volume. Based on the different density of concrete, three types of concrete are distinguished:

  • Lightweight concrete: 800 to 2,000 kg / m³
  • Normal concrete: 2,000 to 2,600 kg / m³
  • Heavy concrete: from 2,600 kg / m³

With reinforced concrete, the density increases on average by 100 kg / m³.

heavy concrete

The high dry bulk density of heavy concrete is achieved through the use of appropriate aggregates. Typical surcharges for heavy concrete would be:

  • lodestone
  • barite
  • ilmenite
  • hematite
  • Heavy metal slags (chrome or lead coatings)

Applications in building construction and civil engineering can be found, inter alia, as bridge bearings, but also in house construction. Here, the base plate can be executed in heavy concrete, if this is in groundwater.

lightweight concrete

Even with lightweight concrete, the dry bulk density is defined by the aggregate. Here, different supplements can be used, which are first divided according to their pore properties:

  • Supplement with closed structure (LBG lightweight concrete)
  • Aggregate with haufwerksporigem microstructure (LBH lightweight concrete)

Above all, good thermal insulation and an excellent eco-balance are regarded as advantages. However, due to the high porosity, there are also corresponding disadvantages. The carrying capacity is significantly reduced, but also the possible absorption of water is problematic, which is why lightweight concrete is not used for exterior and load-bearing walls and components. The use is often made for lightweight partitions or ceilings (especially attic). Contrary to popular belief, gas or aerated concrete is not one of the lightweight concretes.

Density and concrete compaction during concrete installation

The bulk density must not be confused with compacting concrete. When compacting concrete, it is important to extract air and excess water from the fresh concrete. Thus, compacting after the installation of concrete is an important quality feature of the respective concrete, while the dry density only defines the type of concrete. So it is basically possible for any type of heavy or lightweight concrete, that the compression is not performed in the required quality.

Tips & Tricks

If no further information on the density of the concrete is made, ie the concrete is described as light or heavy concrete, it is normal concrete with the conventional gross density values. The use of normal concrete is therefore not specified separately, but very well the use of light and heavy concrete.

Video Board: Density of material use in Construction Qty.