What is Strain Hardening?

UHPC has a higher tensile strength than conventional concrete, it also exhibits strain hardening response after initial cracking when properly reinforced with steel fibers. The typical stress strain curve for UHPC is shown in Figure. In the initial stage, the material’s tensile behavior is elastic, which continues up until the first cracking strength (σcc). Following this, the material then exhibits strain hardening up until its peak point (σpc). The strain hardening behavior of segment II is typically characterized by multiple cracks development in the gauge length of the specimen.

Figure above: Typical tensile strain response in UHPC