Concrete is the most widely used man-made material in the world, with an estimated ten billion tonnes manufactured each year. The everyday structures of 21st century life - buildings, bridges, tunnels, roads and pavements, airport runways, power plants and dams - are only possible because of it. The material has its critics, however, and also its drawbacks, thanks to the ugly buildings and 'concrete canyons' that characterised so much of 60s and 70s urban architecture, its tendency to deteriorate unattractively and its general lack of aesthetic appeal. This reputation is fast becoming a thing of the past, as innovations in new materials technology, pioneered by initiatives such as EUREKA project E! 2829 INNOCONCRETE, spearhead a revival in its use by architects, civil engineers and designers.
The catalyst for INNOCONCRETE was a promising new type of ultra high performance concrete called Ceracem, developed and patented by French construction company Eiffage Travaux Publics. Ceracem is produced in a mould by cold casting, without the need for thermal treatment or any other external action. It has a number of other characteristics, including high mechanical resistance, fibre reinforcement and a flowing, self-levelling behaviour, all of which give the material an attractive surface aspect and high durability. However, processing problems and a lack of knowledge concerning the material's other physical properties had limited its commercial potential.
"EUREKA's support was very important to us - the funding it provided was absolutely necessary to carry out the research. Without it, we would not have the scientific underpinning needed to validate Ceracem's impressive properties and demonstrate its commercial potential as an innovative new material."
Piet van Loenhout, Hurks Beton,
Project INNOCONCRETE was established by the five Franco-Dutch partners with the purpose of fully evaluating the material's properties and developing a range of less costly blends of ingredients suitable for a variety of applications and eventual large scale commercialisation. "We knew what the material was capable of, but we had to validate it scientifically," says Philippe de Vriendt, Development Director of the project's main partner, French company Sika S.A, suppliers of construction materials.
Over the next 40 months Ceracem was assessed for its fatigue levels, resistance to fire, water and chemicals, recycling capabilities, stability and strength. One of the material's most compelling properties, the team discovered, was its exceptional resistance to fire - so much so, that the institute that conducted the fire tests has since used the material in the construction of its new fire oven.
The project members also experimented with different mixes of ingredients - aggregates, additives, cement and water - to optimise mixtures for specific applications. Synthetic fibres were added to provide strength and flexibility and reduce any susceptibility to crack. Another problem they needed to overcome was the length of time it took to mix the material; standard concrete takes just two minutes while Ceracem was taking 12. They managed to halve the mixing time to a more acceptable six minutes.
The new, improved Ceracem has a number of significant advantages over standard concrete. As well as being exceptionally fire resistant, it is waterproof, highly durable and as strong as steel. Considerably less of the material is required for a structure or component, which represents a significant saving on raw materials. It also enables structures and components to be lighter in weight and generally less 'bulky', which in turn allow for greater flexibility and elegance in their design. "With Ceracem, we can cast a very long beam that is both strong and a third of the volume and weight of one made from standard concrete," explains de Vriendt, an achievement which Eiffage has demonstrated to impressive effect in its work on the expansive toll gate roof of the spectacular Millau Bridge which spans the Tarn river in southern France.
The versatile material is available in a range of products, including pre-cast components, ready-to-mix concrete for use on a construction site and as ready-to-use products for specific applications such as grouting. The material was initially manufactured for structural and construction purposes, such as buildings, bridges and tunnels, and is suitable for use by small contractors. However, its lightness, flexibility, smooth surface and ease of use in small moulds is making it increasingly popular among designers for the manufacture of contemporary furniture and bathrooms.
"The material can save companies up to 30% construction time when applied in pre-cast concrete sandwich elements," explains Piet van Loenhout, Director of Dutch pre-cast concrete manufacturer Hurks Beton. "If you are constructing the façade of a building, for example, the sandwich concrete panels can be pre-cast and the window framework installed and glazed in the factory prior to delivering the complete section to the construction site. It can then be swung into place by the site's tower crane directly from the truck without the need for scaffolding, representing a further saving in cost."
"The material can save companies up to 30% construction time when applied in pre-cast concrete sandwich elements. And there is no need for scaffolding, representing a further saving in time and cost."
Piet van Loenhout, Hurks Beton,
Since the project's completion the partners have been using Ceracem for their own construction and manufacturing purposes. Hurks Beton has utilised it in pre-cast form in approximately15 projects to date, while with 70+ subsidiaries worldwide, Sika is in an ideal position to promote its use globally. The long-term plan is to set up a company to exploit the product's commercial potential more widely, and to educate architects, designers and the construction industry as to the superior constructional qualities of this innovative material. Meanwhile, development work is ongoing to resolve on-site casting issues and to reduce the cost of Ceracem still further, with a view to making it more cost effective in the greater volumes needed for larger civil engineering projects.
"EUREKA's support has been very important to us," says van Loenhout. "The funding it provided was absolutely necessary to carry out the research. Without it, we would not have the scientific underpinning needed to validate Ceracem's impressive properties, such as its fire resistance, and demonstrate its commercial potential as an innovative new material."