Fracture examination in concrete through combined digital image correlation and acoustic emission techniques

• Image correlation and acoustic emission techniques are simultaneously applied.
• Acoustic energy analysis is performed to find the size of fracture process zone.
• Evolution of fracture process zone by both techniques are compared and analyzed.
• Size effect is discussed on the growth of fracture process zone.

In order to build sustainable structures, the study of mechanical behavior must integrate with local phenomena, e.g. fracture propagation and localization zone. Fracture in concrete usually develops in the form of localized zone of microcracks which then coalesce into macrocrack of significant crack openings. In this paper, fracture process in geometrically scaled concrete beams under bending test is analyzed. Acoustic emission (AE) and digital image correlation (DIC) techniques are simultaneously applied to identify fracture parameters such as crack openings and size of fracture zone. The AE technique is useful to identify the location of fracture growth due to microcracks and macrocrack, however, DIC is useful to measure crack openings at various locations of crack. The location of crack tip is also estimated from both techniques. It is observed that the two techniques in coupled position proved effective in identifying the fracture process zone and cracking mechanisms of concrete.