Experimental Method to Determine Extension of Fracture‐Process Zone

Abstract
A multicutting technique is introduced, which can be used to determine the extension of the fracture‐process zone together with the conventional compliance method. A new compliance curve is established from a damaged specimen during multicutting and compared with the compliance‐calibration curve. From the comparison of these two compliance curves the extension of the fracture‐process zone can be estimated. Experimental results of wedge‐opening loaded specimens with a ligament length of 110 mm show that the length of the fracture‐process zone in mortar varies from around 43 mm to 12 mm while the crack is approaching to the boundary. A relation between the length of the fracture‐process zone and the shape of the Kr‐curve is established.