Assessment of Concrete and Reinforced Concrete Beams Incorporating CRT Panel Glass Using Non-Destructive and Destructive Testing Methods

This study examines the feasibility of incorporating cathode-ray tube (CRT) panel glass as a partial replacement of natural aggregate in concrete, aiming to promote sustainable material utilization without compromising structural performance. Nine mixtures were prepared using three cement types—Normal 42.5 N, PC 50M(S-V-L) 42.5 N; Profi 42.5 R, PC 20M(S-L) 42.5 R; and Cement without additions, CEM I 42.5 R—and three CRT contents (0%, 5%, and 10%). A comprehensive experimental program was conducted, including tests on natural aggregates, mortars, and concrete in both fresh and hardened states, as well as flexural testing of reinforced concrete beams, supported by ground-penetrating radar (GPR) and digital image correlation (DIC) measurements. The results revealed that replacing up to 5% of natural aggregate with CRT glass had negligible effects on workability and density while slightly improving compressive and flexural strength. At 10% replacement, a minor reduction in strength and ductility was observed. Durability-related parameters, such as water absorption and carbonation depth, increased slightly but remained within acceptable limits. Flexural tests confirmed that beams with 5% CRT content exhibited comparable load capacity and crack propagation to reference beams. This study represents the first combined application of Digital Image Correlation (DIC) and Ground-Penetrating Radar (GPR) in evaluating reinforced concrete beams with CRT-modified concrete across different cement types. The results showed that incorporating 5% CRT glass increased flexural tensile strength by up to 15% compared with the control mix, confirming both the structural feasibility and sustainability of such composites. Overall, the findings indicate that CRT panel glass can be effectively utilized up to a 5% replacement level, offering both environmental and structural advantages for sustainable concrete production. Based on the experimental results, a replacement level of up to 5% CRT glass is recommended for structural concrete applications under the tested conditions, where CRT particles replaced the 4–8 mm medium aggregate fraction, as it ensures a balance between strength, ductility, and durability.