Fiber Pullout

The bond-slip relationship between fibers and the surrounding matrix directly influences the mechanical properties of the UHPC composite. Bond-slip response is activated when fibers bridge cracks that are trying to open further. The resistance they offer against cracking opening promotes beneficial multiple cracking and strain hardening tensile behavior. However, the fiber-matrix bond characteristics are carefully tailored to the strength of the matrix and the characteristics of the fiber to achieve an optimal UHPC response.

Figure above: (a) Pullout test setup;  (b) Pullout performance of Hiper fiber and smooth fiber