The Effect of Changing the Maximum Aggregate Size on the Behavior of Reinforced Shear Key Specimens with Carbon Fiber Grid Under Direct Shear

In recent years, the use of alternative reinforcement materials in concrete members has become increasingly widespread due to their distinct properties, most notably their lightweight nature and corrosion resistance. Consequently, it has become essential to understand the behavior of structural elements reinforced with these materials and to predict their performance when subjected to various loads and stresses. In this study, a carbon fiber grid (CFG) was employed to reinforce a concrete structural member to investigate its behavior under direct shear stresses. This research aims to study the effect of changing the maximum aggregate size on the behavior of shear key specimens reinforced with CFG. The experimental study consisted of nine specimens reinforced with longitudinal T700 Carbon Fiber Grid, examining three maximum aggregate sizes, namely, 2.36, 4.75, and 9.5 mm, and three reinforcement ratios (ρ) of Max, Min, and average. After conducting the required tests, the values of shear stresses, slip, and dilation obtained from the test specimens were calculated. Additionally, the test results for these specimens were compared with each other. The results showed that at the maximum reinforcement ratio, increasing the maximum aggregate size to 9.5 mm decreased the shear capacity. Shear keys with maximum reinforcement ratio showed a decrease in the shear capacity by 27% when the maximum aggregate size increased from 2.36 to 9.5 mm.