What is spun concrete?

Spun concrete is not a conventional concrete, but refers to concrete parts that are produced by a special manufacturing process. Where spun concrete is used, exactly how it is made, and what special properties it has, read this article.

Application of spun concrete

Spun concrete refers to concrete parts produced by a special manufacturing process. These are always components that have a so-called centrally symmetric structure. These include:

  • columns
  • pier
  • Pipes made of concrete and
  • Support

The shape does not necessarily have to be rounded. Also square, oval or rectangular diameters are possible. The maximum diameter that can be produced in this process is about 3 meters.

production mold

The production takes place by means of rotating roller bodies and steel molds. By rotating at 600 to 900 revolutions per minute rolls, the poured concrete is compressed from the inside to the outside.

Depending on the type of shapes, different pillars, columns or beams can be made. They are always hollow inside.

Special properties

Since the surplus water runs inwards, but the heavy concrete parts are pushed further and further outwards, the result is a concrete with a very low water cement content of only 0.25 to 0.30.

This makes the spun concrete particularly dense and therefore also highly resistant. The high strength results from the low content of water cement and the high compression due to the centrifugal forces of the rotating rollers. The load-bearing capacity of spun concrete is very high. In some cases concrete strength classes of C100 / 115 or even higher can be produced.

Because of the dense surface, the concrete is less susceptible to corrosion. The smooth, dense surface offers good protection against the weather and can be processed by conventional methods.

When processing, however, care must be taken to ensure that the rotation-driven compression from the inside to the outside creates a not quite uniform structure. This is statically important because the individual layers can each have different stiffnesses.

In addition, one must assume a different shrinkage behavior of the individual layers of different densities.

Possible problems with spun concrete

In some cases - due to inaccurate production - too high a water-cement value can occur. In this case, the desired strength of the concrete is not or not achieved at all points.

It is particularly problematic if individual weak points remain in the material, which are not always visible from the outside as pores. By remaining in the concrete water can also suffer frost resistance, in addition, such vulnerabilities can compromise the strength of the entire component, if they are located in an unfavorable position.

Tips & Tricks

Further advantages, which have, for example, masts made of spun concrete, are: protection against vandalism (spun concrete can practically not be damaged) but also high fire resistance and high strength also a high resistance to extreme vibrations. In addition, due to the high-density surface, the effects of aggressive environmental influences such as chemicals in the air are practically not dangerous for the concrete.

Video Board: Concrete pre-stressed pole making machine/ concrete spun pole machinery/concrete pole machine