Assessment of Flexural Performance of Sustainable RA-SCC Beams Reinforced with Steel Fibres Using Digital Image Correlation Technique

The Digital Image Correlation (DIC) method is an emerging technology experiencing significant growth, offering a cost-effective means of measuring techniques to determine displacements, crack width, and crack pattern. This research explores the potential of employing the DIC method to assess the load-deflection behaviour of sustainable self-compacting concrete beams strengthened with steel fibers. An experimental study was presented to investigate the behaviour of reinforced SCC beams made of 100% recycled aggregates (RA). Two types of steel fibres (SF), namely micro- and hook-ended, were utilised at different volume fractions (Vf) of 0.5 and 1%. Hybrid steel fibre (a combination of micro and hooked ends) was also utilised in this investigation. A simple and costeffective treatment involving the impregnation of recycled aggregates (RAs) with a cement-silica fume slurry (CSFS) has been proposed to improve their characteristics. The experimental program comprised seven RA-SCC beams subjected to four-point loading until failure. The beams are classified into two groups: the first group comprises two non-fibrous beams made with natural and recycled aggregate, while the second group includes five fibrous beams reinforced with steel fibres by two percentages, 0.5 and 1%. Within all tested beams, one natural aggregate beam served as the control, lacking any recycled aggregate, while the remaining samples were made with 100% treated recycled aggregate. Furthermore, this study utilised the DIC methods to capture the deflection response, crack width, and crack pattern and morphology of the fibrous and non-fibrous beams with treated recycled aggregate, micro-SF, hooked SF, hybrid SF, and volume fraction of SF. The experimental results showed that the utilisation of RA reduced the ultimate flexural load of reinforcement SCC beams by approximately 12% in comparison to the reference beam.