Results in Engineering (Mar 2025)
Shear strength and behavior of eco-friendly RC corbels
Abstract
The use of efficient and environmentally friendly materials is a priority in the construction industry. In this study, the behavior of reinforced concrete corbels made of recycled concrete aggregate (RCA) was investigated. Twenty models were created and categorized into five Groups to examine various factors influencing the characteristics of the corbels. These factors included the replacement ratio of natural coarse aggregate with varying proportions of RCA, with a replacement ratio of 0 % designed for the reference mixture; the other mixtures had replacement ratios of 20 %,40 %, and 60 %. Additionally, the study assesses the amount of main and secondary reinforcement, the shear span-effective depth ratio (a/d), and compressive strength. The influence of these variables on ultimate load capacity, load-deflection curves, crack pattern, initial stiffness, and energy dissipation was investigated. The results indicated that the use of recycled concrete aggregate did not significantly affect the pattern of cracks, type of failure, and energy dissipation capabilities. At the same time, it had a modest impact on the ultimate load capacity, with a decrease of 4.4 %, 8.6 %, and 16 % at a replacement ratio of 20 %,40 %, and 60 %, respectively. Correspondingly, deflection increased from 3.63 mm to 4.27, 4.92, and 5.61 mm at the same replacement ratio. Furthermore, it was also noted that increasing replacement ratios resulted in a slight decrease in initial stiffness. The ultimate load capacity of the corbels was predicted using the theoretical equations proposed by the provisions of the ACI 318 code and the equations proposed by previous literature. The results indicated that using the equations proposed by Hwang et al. and Chetchotisak et al. provided more accurate estimates compared to the other models, yielding a coefficient of variations (COVs) of 4.8 and 5.1 %, respectively. In contrast, the values derived from the code equations were significantly more conservative.
