High resistance concrete: Concrete with different characteristics
Important characteristics of concrete are the workability of fresh concrete, the maximum particle size of the aggregates, its compressive strength (described by its compressive strength class) as well as its resistance to environmental factors (described by its exposure class). The manufacturer is responsible for providing a concrete that satisfies technical demands and demonstrates the properties required. The client must stipulate the requirements that the concrete needs to meet.

Custom concrete: Concrete with a specific composition (custom concrete)
Custom concrete is concrete whose raw materials and composition are stipulated to the manufacturer (Beton Lana GmbH) by the client, e.g. the cement content, the additive content or specifications regarding the particle size distribution curve or the maximum particle size. The manufacturer is responsible for supplying a concrete with the specified composition.

Lightweight and aerated concretes with feed pumps (up to 80 m)
Lightweight concrete is concrete with a dry density of less than 2000 kg/m3. It is manufactured using synthetically produced aggregates or natural stone aggregates. From both construction and economic standpoints, heat-insulating lightweight concrete often provides a favourable alternative in structural engineering to normal concrete, due to its good insulating properties.

The reduced density in relation to normal concrete is generally achieved through:

• permanent voids between the aggregate particles (inter-particle voids)
• use of porous, light aggregates.

(Exceptions to this are foamed or cellular lightweight concrete).

Lightweight concretes are commonly used with reinforcement for structural engineering work requiring medium and high concrete strengths. They can be considerably lighter than normal concrete but simultaneously demonstrate high compressive strengths. Expanded clay and expanded slate are used almost exclusively as aggregates in their manufacture.

Polyester concrete: Polyester concrete can be used relatively easily to provide insulation coatings and for insulating cavities as well as for levelling and coating application layers. It is possible to manufacture this concrete with very low weights (200 to 250 kg/m3) and high heat insulation properties. With a somewhat higher density, strengths of up to 2.5 N/mm2 can be achieved.

Self-Compacting Concrete (SCC)
“Self-compacting concrete” (SCC) is a high performance concrete that is able to virtually self-level by force of gravity without the need for any additional consolidating work, and is able to flow into all concrete reinforcement cavities without leaving gaps, completely filling the formwork.

Noise pollution is noticeably reduced thanks to the fact that no consolidation work is required, conditions on site are improved, manpower requirements reduced and the placing speed of the concrete increased.

Exposed (or Fairfaced) Concrete
Areas of concrete whose upper surfaces remain visible are known as exposed concrete and must thus fulfil particular aesthetic requirements. The visible surfaces of exposed concrete display a mirror image of the formwork and so during production of the formwork boards, particular attention is paid to the material, structure and release agent as well as to ensuring that the concrete is placed correctly in the mould.

Concretes for exposed concrete components must be manufactured from particularly high quality raw materials, and must be of a particular consistency and workability. Their production demands precise workmanship in the manufacturer’s works and only the smallest variations in dosing are acceptable.

Pigmented Concrete
Colour is an important element in exposed concrete facades. By using different pigments for colouring the concrete it is possible to provide ready mix concrete in different shades such as black, red, green or yellow.

Water-Impermeable Concrete
Concrete building components that are partly or completely embedded in the ground may prevent water ingress without needing to use additional sealing measures (“White Tank”). The maximum water penetration depth is usually less than 50 mm or 30 mm in concrete with higher resistance levels. To achieve this, water impermeable construction components must be manufactured from a special concrete compound.

White Tray
The term “White Tray” is used to describe a structure that is water impermeable. The outer walls, floor slab and ceiling are all manufactured from water impermeable concrete, for which no additional sealing layer and also no drainage are necessary. Caulking must be applied to the construction and expansion joints, and the crack width limit in the reinforced concrete must be calculated to no more than 0.2 mm, depending on water pressure.

High Strength Concrete
Concrete with a higher compressive strength class then C50/60 is designated high strength concrete. It is characterised by a dense structure, it has very few capillary pores and is mainly utilised where the concrete will be subjected to high compressive and mechanical stresses.
Higher strength concretes can be produced by the addition of high performance plasticisers, very fine-grained additions (silica fume) and special kinds of aggregates.

Shotcrete
Shotcrete is concrete that is conveyed using compressed air in pipes or hoses to a nozzle, through which it is applied in layers and simultaneously compacted. This concreting process is particularly important when constructing tunnels for securing uncovered rocky or loose stone surfaces, and also for improving and strengthening concrete and reinforced concrete structures.

Shingle Concrete / Drainage Concrete
Drainage concrete is concrete that has many inter-particle voids and cavities for drainage purposes.  The inter-particle voids result from the use of a tightly confined group of particles, where the individual particles are only cemented to one another where they meet by thin layers of cement paste.

 
Heavy Aggregate Concrete
Heavy aggregate concrete is a type of concrete whose density is greater than 2.8 g/cm3. It is produced with additions such as barites, scrap iron or iron ores such as lodestone or haematite and is used as radiation protection to shield areas from X-rays and gamma radiation. It often renders any further shielding superfluous. In addition, heavy aggregate concrete is suitable for use as ballast weight, for example for crane counterweights, bridge abutments etc.

Fibre-Reinforced Concrete
By mixing fibres into the concrete certain properties such as “green” strength, tensile strength, impact strength, brittleness, displacement behaviour (ductility) and propensity to shear can be improved. The fibres are embedded in the matrix (hardened cement paste) and above all, depending on the type of fibre, impede the formation and spread of cracks in new or hardened concrete.
To date, only synthetic, glass and steel fibres have achieved any real practical importance.

Underwater Concrete
Underwater concrete is concrete that is used under water. So as to prevent the concrete from separating out during concreting, specific procedures are necessary, such as the use of fixed chutes (tremie placement) or the use of concrete pumps. The concrete must demonstrate a high cohesive capacity and good workability. The cement content must therefore amount to at least 350 kg/m3. Underwater concrete is used particularly for slurry walls and in groundwater as a barrier layer to floor slabs.

Concrete for large construction components
With large components particular attention must be paid to temperature changes resulting from hydration heat, which can lead to early formation of cracks and thus limit the durability of the material. Special cements and additives are used during production to deal with this issue.

Synthetically modified concrete
In synthetically modified concrete up to 50% of the cement mass can be replaced by synthetic dispersions such as epoxy resin, polyester resin, acrylic resin or latex, among other things. All of the properties of fibre-reinforced concrete, and above all its chemical resistance, can be considerably improved by synthetic modification. It is however important to bear in mind that the risk of stress and strain related distortions in general becomes considerably greater.

Recycled Concrete
Recycled aggregates are construction materials that are reclaimed through the processing of waste building materials and which can be used as aggregates for the production of new concrete. Suitable waste building materials can consist of broken up concrete or construction rubble.