Introduction to UHPC Concrete

March 23, 2022 | Introduction to UHPC Concrete

The history of concrete could be traced back to the times of the Roman Empire, but the history of modern concrete is commonly considered to begin in 1824 when Joseph Aspdin patented a material named “Portland cement”. The current concrete is referred to the material resulting from blending of cement, water, fine aggregates, coarse aggregates and other minerals in a specific proportion. The major disadvantages of concrete is the low tensile strength and brittleness of such type of material. In 1849, Joseph Monier, a French gardener, published a patent for reinforced flowerpots by means of mixing a steel wire mesh to a mortar shell to solve the problems associated with concrete and that is now considered as the beginning of “reinforced concrete structures”. Incorporating steel reinforcement not only increases the strength of concrete structure, but also significantly improves its ductility. Nowadays reinforced concrete is widely used in construction and infrastructure sectors for many types of structural components including slabs, walls, beams, columns, foundations, frames and more.

Example of a typical reinforced concrete use in construction

As the requirements for construction industry became more demanding, the problems of concrete became more and more obvious, including unstable and uneven matrix, low tensile to compressive strength ratio, high weight to strength ratio, low ductility and poor durability. In the 1970s, a new type of concrete called “high-strength concrete (HSC)” was developed by employing low water-to-cement ratio, careful selection and gradation of aggregate particles and water-reducer admixtures to achieve compressive strength from 50 to 120 MPa and higher durability. However, HSC proved to become more brittle due to the increased compressive strength. This problem was not solved until the term “fibre-reinforced concrete (FRC)” was developed by involving different types of fibers into the HSC matrix in the early 1980s. The addition of fibers could effectively improve the tensile strength, toughness, ductility and cracking resistance. In 1994, the compressive strength of concrete was further increased to above 120 MPa by using an optimized particle size distribution of cement alongside fine and ultrafine particles. Such type of concrete is called “ultra-high-strength concrete (UHSC)” which is also characterized by high durability and self-compactability.

On the basis of the above-described technologies, Reactive Powder Concrete (RPC) with extremely low water-to-cement ratios, dense packing density composed of very fine powders (cement, sand, quartz powder and silica fume, with no coarse aggregates), steel fibres and superplasticizer was created in 1995. At present, Ultra-High-Performance Fibre-Reinforced Concrete (UHPFRC) has replaced the term RPC gradually to represent such a type of concrete with superior compressive strength (above 120 MPa) and tensile strength, outstanding durability, high toughness and ductility. As UHPFRC usually has a minimum amount of fibres to ensure certain degree of ductility, it is more common to use the term Ultra-High Performance Concrete (UHPC) to refer to UHPFRC.

Comparison of mechanical properties of normal, high strength, and UHPC concrete

Compared to traditional concrete, Ultra-High Performance Concrete exhibits outstanding mechanical properties, superior ductility and toughness, and extraordinary durability. The mechanical properties of UHPC make it an ideal material for applications where the strength is the predominant design parameter and where the size of elements can be reduced to become smaller, thinner, and more aesthetically pleasing. The ductility and toughness in tension allows the tensile strength of UHPC to be considered in both service and ultimate limit state for flexure, shear, and torsion, especially when seismic design is required. The durability and longevity of UHPC extends its service life and reduces the maintenance cycles in an outdoor or severe climate-exposure environment. Although the technology and development of Ultra-High Performance Concrete have been well investigated and documented from micro- to macro-level, it is still difficult to promote UHPC widely due to the challenges of complicated production process and high cost. The complicated production process mainly results from too many ingredients used (up to 15), which leads to both difficult handling and high cost.

The performance of produced UHPC is highly dependent on the quality of contractors and workers. High cement content is another factor to increase the cost of UHPC while also increasing the emission of carbon dioxide which is not environmentally friendly. Replacing the cement by silica fume or other accelerators is an effective method of reducing the cement content in UHPC; however, silica fume has a wide range of physical and chemical specifications depending on the point of harvest in the process. The varying characteristics of silica fume become critical for UHPC which requires a more precise mix set up. Other drawbacks of using silica fume are its rapidly increasing cost and its impact on surrounding ecosystem since the dust of silica fume is harmful to the workers and not environmentally friendly. Another key component of Ultra High Performance Concrete, steel fibers are widely used to enhance the fracture and ductility performance of UHPC, but the amount should be limited. The high amount of steel fibers would not only increase the cost, but also disrupt the hydration process and introduce additional air into the concrete matrix. Improving the effectiveness of steel fibers in the matrix is the key to guarantee the high engineering properties and low cost of UHPC.

Environmental Footprint of Normal Concrete vs Traditional UHPC vs UHPC 2.0

By realizing the benefits as well as limitations of modern UHPC, ceEntek Pte Ltd is dedicated to developing a new generation of UHPC, UHPC 2.0, which possesses superior mechanical and durability properties, ideal fresh properties, easy handling, low cost, environmental friendliness and worldwide availability due to its few ingredients. UHPC 2.0 has a wide product family which could be applied to federal and municipal infrastructure such as roads and bridges, water conservancy facilities, marine/offshore engineering, military facilities and precast construction. With the dire state of global infrastructure it is the innovative Ultra-High Performance Concrete solutions such as uhpc bridge overlays, prefabricated bridge components, bridge girders, seismic columns, piles, link slabs, cladding and waffle-deck panels that are gaining popularity and acceptance within the construction industry. We at ceEntek are happy to offer our expertise in UHPC products and applications for all interested parties. For more information, please contact us at