مقاله انگلیسی رایگان در مورد رفتار برشی تیرهای بتنی سبز تقویت شده با میلگردها – الزویر 2021

Abstract

Keywords

1. Introduction

2. Experimental program

3. Test results and discussions

4. Predictions of shear capacities

5. Conclusions

Declaration of Competing Interest

Acknowledgments

Data availability

References

Abstract

This study investigated the shear performance of large-scale green concrete (GC) beams reinforced with basalt fiber reinforced polymer (BFRP) bars and stirrups. The GC concept was employed in this study by partially substituting the cement content with 35% by weight of industrial by-products (fly ash and silica fume). The main test variables were the reinforcement ratio, the shear span to depth ratio (a/d), and the spacing between stirrups. Three beams were transversely reinforced with steel stirrups to serve as a control. Experimental results indicated that the ultimate shear capacity was significantly increased at higher reinforcement ratios. Such effect was less pronounced in beams with reduced spacing between stirrups. In addition, the BFRP stirrups were effective in reducing the diagonal shear crack width and increasing the ultimate shear capacities of the tested beams. On the other hand, beams with a higher a/d ratio have shown higher deflection and reduced ultimate shear capacity. Comparing the experimental results of the current study with the current design codes and guidelines provisions, the CSA-S806-12 has shown the best predictions with a mean experimental to predicted shear (Vexp/Vpre) ratio of 1.43 ± 0.29.

1. Introduction

There is a growing motivation from researchers and construction practitioners towards the implementation of FRP composites as an alternative to conventional steel reinforcement [1], [2], [3]. Keeping in mind that the corrosion in steel is one of the main reasons behind the deterioration of reinforced concrete (RC) structures [4], the use of anti-corrosive FRP bars can play a crucial role in addressing the corrosion issue in RC structures. Nowadays, basalt FRP (BFRP) bars are gaining more popularity in the literature due to their lower price than carbon FRP bars, and their comparable mechanical features to the glass FRP (GFRP) bars [5], [6], [7], [8], [9], [10]. Moreover, BFRP bars have shown better thermal resistance compared to GFRP bars [11]. The shear behavior of RC beams reinforced with GFRP bars and stirrups has been well documented in the literature [12], [13], [14], [15], [16], [17]. However, a few studies have investigated the shear behavior of RC beams reinforced with BFRP bars [2], [18], [19]. For instance, Tomlinson and Fam [20] demonstrated that for BFRP-RC beams without stirrups, the shear strength has increased by 39.7% as the reinforcement ratio went from 0.39% to 0.84%, whereas it was increased by 47% with stirrups. Likewise, Issa et al. [2] also noted that the BFRP-RC beams with BFRP stirrups exhibited much higher shear capacity than beams with no BFRP stirrups. However, their effect was less pronounced at higher reinforcement ratios. They also observed a significant increase in the shear capacity of 32% when the reinforcement ratio was increased from 0.8 to 1.3%.