Axial capacity of rubberized RC short columns comprising glass powder as a partial replacement of cement

• Published in: Structures (Oxford) 2024-06, Vol.64, p.106612, Article 106612
• Main Authors: Elsayed, Mahmoud, Almutairi, Ahmed D., Hussein, Mostafa, Dahish, Hany A.
• Format: Article
• Language: English
• Subjects: Crumb rubber; Mechanical properties; Optimization; Reinforced concrete columns; Sustainable development; Waste glass powder
• ISSN: 2352-0124; 2352-0124
• DOI: 10.1016/j.istruc.2024.106612

The main goal of this research is to investigate the impact of using waste glass powder (GP) and crumb rubber (CR) as partial substitutes for cement and fine aggregates (FA) in concrete, respectively, on the behavior of reinforced concrete columns. Consequently, nine different concrete mixtures were produced, comprising three replacement levels of CR (0%, 5%, and 10%) by FA volume and three replacement levels of GP (0%, 10%, and 20%) by cement weight. To determine the axial capacity, toughness, and stiffness of the columns, nine columns (one column for each mixture) were prepared and tested under concentric loading. The results showed that the axial capacity and toughness of the tested columns significantly improved with the addition of GP up to 10%, while the opposite observation was found for CR. For replacement levels of cement with GP more than 10%, the capacity and toughness of rubberized concrete columns decreased. The stiffness of the rubberised concrete columns increased as the GP content has increased. Taking engineering and environmental concerns into consideration, 5% CR and 20% GP are the most appropriate substitution proportions in the concrete mixture. The inclusion of 10% or 20% of GP without CR induced an improvement in the compressive strength of 14.5% and 1.9% and an improvement in the ultimate axial capacity of 14.1% and 5.2%, respectively. The ability of international design codes (ACI and CSA) formulations for conventional concrete to estimate the axial capacities of reinforced concrete columns comprising CR and GP was examined. ACI 318–14 yielded the most accurate predictions for the axial capacities with ratios ranging from 1.06 to 1.14 with a coefficient of variation and a standard deviation of 2.5% and 0.03, respectively. Finally, an equation was provided for predicting the axial capacity of the columns. The predictions from the developed and previously available equations were compared to experimental results utilizing various statistical metrics. The results showed that the proposed equation's predictions agreed well with the experimental results. The proposed model equation outperforms others in terms of RMSE (3.84) and R2 (0.9921). The developed equation can be used for predicting the axial capacity of rubberized RC columns containing WGP with high accuracy and low prediction error.