Abstract
This paper experimentally investigates the effects of the characteristics of coarse aggregate on the shear behavior of reinforced concrete slender beams. A total of eight reinforced concrete (RC) beams were fabricated with four types of coarse aggregate densities and mineralogy by utilizing limestone, quartizate, scoria, and steel slag aggregate. Beams were cast both with and without shear reinforcement and tested under three-point loading configuration. The experimental results indicated that all beams failed in a similar fashion, due to diagonal tension shear crack. The aggregates with high abrasion resistance resulted in a higher ultimate shear strength. The normalized shear strength for beams cast with similar compressive strength category generally followed an increasing trend with abrasion resistance and density (i.e., 7.9 for beams with limestone aggregate, 9.9 for quartzite aggregate, and 11.6 for steel slag aggregate). It was observed that the initial stiffness of the beams was independent of the aggregate type and was solely reliant on the concrete's compressive strength. For the beams without shear reinforcement cast with similar compressive strength category (high-strength concrete), the peak and post-peak displacement capacity increased with the toughness of the coarse aggregates (limestone, the quartzite, and the steel slag). However, the variation in the peak displacement capacity for the beams with shear reinforcement was very insignificant, irrespective of the aggregate type. The experimental results in terms of the ultimate shear strength were validated against models proposed in the literature, including the recommended design equations of various codes of practices. Additionally, a shear strength model was proposed using the simplified ACI 318 [1] equation. The proposed model showed predictions that closely matched the experimental results. (C) 2020 Elsevier Ltd. All rights reserved.