Fracture Models and Effect of Fibers on Fracture Properties of Cementitious Composites—A Review

. 2020 Dec 2;13(23):5495. doi: 10.3390/ma13235495

$K_{I} < K_{I c}^{i n i}$	Elastic Stage; No Crack
$K_{I} = K_{I c}^{i n i}$	Crack initiation
$K_{I c}^{i n i} < K_{I} < K_{I c}^{u n}$	Crack stable propagation
$K_{I} = K_{I c}^{u n}$	Crack begins to destabilize and expand
$K_{I} > K_{I c}^{u n}$	Crack instability propagation