Glossary: Micro-reinforcement
Micro-reinforcements made of steel, carbon, plastic, or glass fiber fabric

The backbone of DUCON technology.

Micro-reinforcements are fabric mats made of materials such as stainless steel, black steel, carbon, plastic, or glass fiber, which, in combination with ultra-high-performance concrete, result in a composite material with unique properties.

The composite material, in which the fabric mats are first laid out and then infiltrated with mortar, has been known for over 100 years. The advantage of this method: Today, the DUCON technology based on it allows for variations in mat structure, resulting in different material behaviors such as high load-bearing capacity, large plasticity (ductility), crack resistance, high durability, large energy absorption and impermeability, as well as high impact resistance and thermal conductivity.

Since when have micro-reinforcements been used?

As unusual as it may sound: Micro-reinforcements were first used in connection with concrete in shipbuilding. Over 100 years ago, the Frenchman Joseph Louis Lambot experimented with a so-called Ferciment, consisting of concrete and a wire mesh. His idea: The novel composite material should be used as a wood substitute in shipbuilding. Parallel to this, research on micro-reinforcements was also conducted in America. However, it was Joseph Monier who patented some of the first real products made of iron cement from 1867 onwards. He initially developed wire-reinforced flower pots made of iron concrete, later followed by tubes, containers, and even stairs. In the mid-1940s, Pier Luigi Nervi finally produced tensioned surface structures and aptly called the building material used for it, consisting of micro-reinforcement and cement, Ferrocement.

What is Ferrocement?

As the word suggests, Ferrocement or Ferroconcrete is a composite material consisting of reinforcement with closely spaced wire meshes (Ferro) and mortar (Cement). These closely spaced wire meshes were often used as additional reinforcement for concrete steel reinforcement. In principle, Ferrocement is a kind of combined reinforced concrete. Unlike conventional concrete, no formwork is necessary for Ferrocement with micro-reinforcements in combination with shotcrete. However, there is a catch. The necessary reinforcement work is extremely complex and therefore cost-intensive. This circumstance led to numerous developments over the years. One of them is fiber-reinforced concrete, in which fibers made of different materials are first sprinkled into the formwork and then infiltrated with mortar. Another one is DUCON Ultra-High-Performance Concrete (UHPC), which is an advancement of fiber-reinforced concrete. The internationally patented DUCON technology, since 1999, consists of a spatial, multilayered micro-reinforcement made of wire mesh or other materials, which is filled with ultra-high-performance concrete (UHPC). Its advantage: Variations in the mat structure allow for different material behaviors such as high load-bearing capacity, large plasticity, crack resistance, high durability, large energy absorption and impermeability, as well as high impact resistance and thermal conductivity. These high-performance properties are achieved with a low component thickness starting from 25mm, which is significantly different from conventional reinforced concrete, which requires at least three times the thickness and weight.

Where is DUCON Ultra-High-Performance Concrete with micro-reinforcements used?

• For lightweight construction - DUCON is the ideal solution for components with low thicknesses and for components where free formability is desired.
• For dense construction - DUCON can easily be combined with conventional reinforcement and can also be used as a protective layer.
• For ductile construction - DUCON allows components with high deformability and high energy absorption as well as with low layer thicknesses.
• For demanding surfaces - Due to very fine crack formation and only small crack widths, DUCON is excellent as high-quality exposed concrete.
• For construction in existing structures - DUCON allows thin reinforcement layers, is suitable for the reinforcement of slabs, beams, and columns, and offers itself as a replacement for thin precast elements.

What materials are used for DUCON micro-reinforcements?

Micro-reinforcements made of stainless steel
Experience has shown that steel remains the best choice for micro-reinforcement. The material properties can be optimally combined with those of DUCON mortar, resulting in a composite material with numerous advantages over conventional reinforced concrete. In addition to traditional black steel, an alloyed chromium-nickel steel (stainless steel) has been used since 1999.

Micro-reinforcements made of carbon fabric
Instead of traditional steel, carbon fiber fabric is used as the supporting backbone of ultra-high-performance concrete. DUCON with multilayer carbon fabrics was introduced in 2008 and also resulted in patent protection (German GM: DE20 2008 009 564 U1). However, compared to steel fabrics, the application was limited for economic and technical reasons.

Micro-reinforcements made of plastic or glass fiber fabric
Another alternative to steel reinforcements: lightweight and more cost-effective micro-reinforcements made of plastic or glass fiber fabric compared to carbon. Due to the high alkalinity of concrete, the use of a special alkali-resistant AR glass is required, but its durability is unfortunately limited. Plastic fabrics have the disadvantage of a low modulus of elasticity, which is usually lower than that of concrete and therefore behaves too elastically in load-bearing components. The result: The concrete cracks before the load-bearing capacity of the reinforcement kicks in.