UHPC is a family of concretes offering a combination of material and performance characteristics that create products with:
– Ductility, which is the ability to support tensile loads even after initial cracking
– Ultra high compressive strength (up to 200 MPa/29,000 psi)
– Extreme durability; low water to cementitious material (w/cm) ratio
– Self-consolidating and highly moldable mixtures
– High-quality surfaces
– Flexural/tensile strength (up to 40 MPa/5,800 psi) through fiber reinforcement
– Thinner sections; longer spans; lighter weight
– New graceful product geometries
– Chloride impermeability
– Abrasion and fire resistance
– No steel reinforcing bar cages
– Minimal creep and shrinkage after curing
UHPC is one of the latest advances in concrete technology and it addresses the shortcomings of many concretes today: It provides high strength to weight ratio, high tensile strength, high ductility, and volume stability. It has a compressive strength 2 to 3 times greater than conventional concrete and a flexural strength 2 to 6 times greater. These mechanical properties of UHPC make it ideal for prestressing applications. In addition to achieving high compressive strengths in excess of 25,000 psi (sometimes greater than 30,000 psi), UHPC is also nearly impermeable.
The higher strengths afforded to UHPC allows increased girder spans while maintaining similar or smaller cross-sectional areas. Costs may be reduced as the lower span to depth ratio of UHPC bridges require less embankment fill while providing more aesthetically pleasing profiles.
Increased span lengths mean fewer support structures such as piers which lead to improved safety when traveling under overpasses and lower environmental impact in water crossings.
Additionally, beam spacing can be increased allowing for faster construction times, lower transportation costs, and increased material efficiency.