Construction projects rely on conventional concretes that are made up of water, cement, and gravel.
These concretes are spread over reinforcing steel bars that will be set in a course of time.
This process has been employed for constructing bridges, walls, buildings, tunnels, roads and railroad tracks.
There is a concrete called Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) is a new formulation manufactured by mixing an accurate amount of short, thin metal fibres to the powdery components.
Unlike conventional construction materials, high-performance concretes are the result of a so-called “integrated structural and material design.”
According to this concept, the material composition is tailored to ensure specific structural performances.
Ultra-high performance fibre-reinforced concrete (UHPFRC) is an advanced reinforced cementitious material. “Ultra-high performance” refers principally to improved mechanical strengths, fractural toughness, and durability.
UHPFRC can be considered as the latest innovation originally developed by Bouygues SA, France, in 1995.
In recent years the collaboration between structural and material engineering led to an integrated design, based on the tailoring of the material’s composition to meet specific requirements for structural applications.
UHPFRC can be considered as the advanced result of this collaboration.
The material was optimised with respect to mechanical strengths, fractural toughness, durability, placing method and time, keeping mixing and casting procedures as close as possible to existing practice.
Ultra-high performance concrete (UHPC) is typically characterised as the material with the microstructure that is significantly enhanced regarding homogeneity in comparison to ordinary and high-strength concretes.
This is the principal argument in explaining the improved strengths and durability of UHPFRC.
Fibres are incorporated in UHPC in order to enhance the fracture properties of the composite material.
The additional role of fibres in UHPFRC, in comparison to the role of fibres in ordinary and in high strength fibre-reinforced concrete, is to provide sufficient ductility of the material in tension without a decrease in stress.
This is achieved by choosing the appropriate type and quantity of fibres.
Fibres used in UHPFRC are typically short, smooth, and straight, while hooked fibres are more often used in high-strength or ordinary concretes.
As a result, an improved building material is obtained; removal of gravel increases the concentration, making the formulation impermeable to water and gases.
This is demonstrated to be an extremely durable building material.
Corrosion is the major problem faced by most building structures. The density and impermeability of the UHPFRC is a potential material capable of providing a tight seal to the structure’s interior.
The accelerated hardening property of this innovative material is effectively used for steep slopes, roads and other constructions related to transportation renovation.
Using fewer raw materials make the structure lighter without compromising its performance.
Source : azobuild.com and actu.epfl.ch
(this article written for 1BINA.my)