Effect of Coarse Aggregate Size on Shear Behavior of Beams without Shear Reinforcement

The effect of aggregate size on the shear behavior of reinforced concrete (RC) beams without shear reinforcement was experimentally investigated in this study. Beams with four coarse maximum aggregate sizes were manufactured and tested to shear failure, including 10, 20, 31.5, and 40 mm (0.39, 0.79, 1.24, and 1.58 in.). Two shear span-depth ratios lambda = 2.2 and 3.0 were considered. After tests, finite element analysis was carried out to simulate the shear failure process. The results showed that the maximum aggregate size had no or little effect on the tensile strength of concrete, while it improved the shear capacity of RC beams. Once cracked, the normal and tangential displacement between the shear cracks occurred simultaneously, and the aggregate interlock worked all the time. Finite element analysis showed the inclined principal tensile stress within the low-middle part of the web and the tip of the diagonal cracks had significant influence on the development of diagonal cracks.