What Is a Hollow-Core Slab?

At Benchmark Fabricated Steel, one of the specialty steel products in Indiana that we make for our steel construction clients is hollow-core slabs. Also occasionally referred to as hollow-core planks, voided slabs or concrete planks, these are precast slabs of pre-stressed concrete that are commonly used in building floors for multi-story apartment buildings and condominiums. While this sort of material can be used in just about any environment, it is especially popular in countries where there has been a major emphasis on precast concrete for purposes of home construction, including countries in Northern Europe and some of Eastern Europe’s former communist countries.

Why is precast concrete so popular? Perhaps the biggest reason is how economical it is. It requires less material to make, which makes it lighter than other types of building materials. It is also able to be assembled quite quickly. This means that property owners looking to create large-scale residential or commercial buildings quickly can use hollow-core slabs to great effect.

The character of precast concrete

A precast concrete slab has tubular holes or voids that run the entire length of the slab, usually with a diameter that extends about two thirds to three quarters of the slab. This is what gives the slab its light weight—significantly lighter than solid concrete floor slabs that would be equally thick, without sacrificing almost anything in the way of strength.

Reduced weight for this building material is important because it helps to cut down on costs associated with transportation, as well as the overall costs of the material.

The slabs typically measure about 120 cm wide and between 15 and 50 cm thick. A steel wire rope reinforces the concrete and prevents it from bending under the weight of the loads it bears. The slabs are also usually made in lengths of anywhere up to 200 meters.

While making hollow-core slabs, workers extrude wet concrete with the pre-stressed steel wire rope from a moving mold. This slab then gets sliced by a massive circular saw with a blade made of diamond to ensure it is hard enough to effectively cut the material. This sort of production in a factory setting makes for a much more efficient production process and better labor.

There are other means of fabricating hollow-core slabs. One example is making hollow-core floor slabs in reinforced concrete, which is not pre-stressed. These slabs get made on carousel production lines to their exact length as a stock product. That length is typically seven or eight meters long. This is one of the most common methods of making hollow-core slabs for housing purposes in Europe.

Then, to soundproof the floor and ensure it meets all modern standards, some sort of soft floor covering must be used to dampen the sound of footsteps. Sometimes, floating floor screeds or rubber strips under the slabs are used as alternative solutions.

For more information about what hollow-core slabs are and their place in the construction industry, contact Benchmark Fabricated Steel to learn about specialty steel products in Indiana.

Categorised in: Specialty Steel Products

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