“…in which, f t,a and ε u,a are the tensile strength and the ultimate strain of aggregate, respectively; f tip t,m is the finite stress at the mortar crack tip; AF is the aggregate fracture index. 37 Furthermore, the critical state of the meso-level crack path criterion 37 is specifically considered in the present study, so that AF = MF c = πηcot(πη), where MF c is the critical mesoscopic fracture index, 37 therefore f t,a ¼ f tip t,m , which results in ω a ω m ¼ πηcot πη ð Þ, and thus Equation ( 17) is finally expressed as…”