This study investigates the applicability of QR‐code‐based speckle patterns for deformation measurement using two‐dimensional digital image correlation (2D‐DIC) in flexure‐dominated reinforced concrete T‐beam experiments. Three reduced‐scale reinforced concrete T‐beam specimens were tested under monotonic four‐point bending. Surface deformation was recorded using two types of patterns: a conventional random speckle (RS) pattern and a QR‐code‐based structured speckle pattern. Full‐field displacement and strain responses obtained from DIC analysis were used to derive moment–curvature relationships and were compared with reference measurements obtained from conventional instrumentation. Results indicate that the QR‐code pattern provides improved correlation stability and reduced strain‐field noise compared with conventional RS patterns, particularly in regions influenced by crack‐induced deformation gradients. Quantitative comparison showed that deviations in ultimate moment and curvature measurements were lower when QR‐code speckles were used. However, due to the limited number of specimens, the study should be interpreted as a pilot‐scale methodological investigation rather than a statistical validation of pattern superiority. The findings demonstrate the feasibility of using QR‐code‐based patterns to improve subset tracking reliability in laboratory‐scale reinforced concrete experiments and provide a robust methodological framework for future DIC‐based structural investigations.
Krishna et al. (2026) studied this question.