Abstract
This study examined the axial behaviour of recycled brick aggregate concrete (RBAC) confined with glass chopped strand mat (GCSM) through an extensive experimental and analytical program. The results demonstrated that GCSM confinement markedly improved both compressive strength and ductility, with strength gains of up to 75% and peak strain increases exceeding 80% in low-strength (LS) mixes, while medium- and high-strength (MS and HS) mixes showed comparatively lower enhancements. Specimens made with type B bricks consistently outperformed those with type C in both strength and deformability, and the confinement effect was most pronounced in LS concretes due to their greater initial ductility and ability to activate external wraps. Confined specimens exhibited improved post-peak behaviour, with positive post-peak modulus values and deformability indices up to 2.6 times higher than unconfined counterparts. Analytical models developed for normalized strength, peak strain, post-peak modulus, and deformability index showed strong agreement with experimental data (R2 = 0.86-0.98) and accurately reproduced full stress–strain responses. These models incorporate key confinement parameters, lateral pressure, brick strength, and unconfined concrete strength, enabling their direct use in design and assessment of GCSM-confined RBAC elements. Overall, GCSM provides a simple, affordable, and sustainable confinement system, offering a practical retrofitting solution for enhancing the strength and ductility of structural concrete, particularly in resource-constrained and sustainability-focused regions.