Betoniek: Lightweight elements of ferrocement

In de media 

microbeton appeared in the trade jouranl ‘Betoniek’ about its ferrocement products and lightweight elements. You can read the whole articlejverscheen in het vakblad Betoniek over haar ferrocement producten en lichtgewicht elementen. Het hele artikel lees je here: www.betoniek.nl 

Ferrocement

Ferrocement is a building material that is composed of a cement-bound mortar and one or more layers of fine mesh reinforcement (‘ferro’). With this, very thin or hollow constructions can be made, with which considerable weight savings can be made.

Ferrocement and reinforced concrete are related materials. They are both cementitious composites reinforced with steel. The cement content in ferrocement is high, which makes the material very strong and gives it a dense surface structure. Various types of cement can be used as a binding agent. Because of its properties, Portland cement (CEM I) is generally chosen. The minimum cement quantity is 600 kg/m³ and the water-cement factor is a maximum of 0.4. The average compressive strength of ferrocement is around 80 N/mm². The size of the aggregate differs greatly from that of normal concrete. Whereas the maximum aggregate diameter of normal concrete is around 30 mm, that of ferrocement is approximately 4 mm. Ancillary materials are also used, such as a substance to prevent hydrogen from forming through the galvanised wire mesh. The grain structure of the sand fraction, as with normal concrete, is an important aspect of the workability and ultimate density of the material. This density is considerable in ferrocement. The material is so dense that water does not penetrate the surface and coverage of 6 mm on the galvanised steel reinforcement mesh is sufficient (Photo 2). This has been established with carbonation measurements and penetration tests. The diameter of the steel is correspondingly smaller. In contrast to bar diameters from Ø6 to about Ø20 mm of normal concrete in the relevant area (balconies, canopies, etc.), wire mesh and bars with diameters from about Ø1 mm to Ø1.5 mm up to about Ø10 mm are used (Photo 2). The reinforcement percentage and the specific bonding area per unit volume are much higher with ferrocement.

Spaarnelicht, Heemstede