Integrated experimental testing and optimisation of numerical data-driven modelling for eco-efficient GI-fibre mortars with recycled crushed waste clay bricks in ferrocement strengthening of RC beams

Ferrocement is a cement-based composite reinforced with steel mesh, offering high tensile strength, crack resistance, and durability, which makes it suitable for concrete repair. Despite these advantages, poor bonding between the mortar, mesh, and the existing concrete can lead to brittle behavior, reduced ductility, and interface failure. To address this gap, this research evaluated 16 reinforced concrete (RC) beams that had been damaged and subsequently repaired using ferrocement, comparing their performance with that of two unstrengthened beams (USB). The ferrocement mortar was fabricated with 100% natural sand (NS) and 50% recycled crushed waste clay brick (RCWCB) as a substitute for NS + 50% NS and varying dosages (0%, 1%, 2%, and 3% by volume of mortar) of low-cost galvanised iron (GI) wire fibres. Furthermore, a data-driven model was created, verified, and optimised in accordance with experimental results. The outcomes reveal that as the GI wire fibres increased, the flexural load of the strengthened beam and the mechanical strengths of the mortar increased. The beam capacity is enhanced with higher dosages of GI fibres, showing a 41% increase for 100% sand and 51% for a mix of 50% RCWCB + 50% sand with 3% GI fibres, compared to USBs. In contrast, the deflection behaviour of the RC beams yielded a 159% increase for 100% sand and a 169% increase for 50% RCWCB + 50% sand, higher than USB. Furthermore, notably higher enhancements in mechanical strengths were registered for mortar fabricated with GI wire fibres, with compressive strength increased by 12%–17%, tensile strength by 45%–56%, and flexural strength by 50%–65% for mortar with 3% GI fibre than without fibre. The data-based model accurately reflects the load-deflection profile, validating its effectiveness, even with minor and major cracks. Conversely, the optimised model demonstrates strong agreement with experimental results, closely matching the observed data across the entire profile. The study recommends using 50% RCWCB as a sustainable alternative to NS with a 3% GI wire fibre to enhance the properties of ferrocement RC beams and promote sustainability.