سلوك القص للعتبات الخرسانية المسلحة العميقة المستمرة الحاوية على الياف مخلفات البلاستيك والمعاد تأهيلها بواسطة شرائح الياف الكاربون البولميرية

Shear Behavior of Continuous Reinforced Concrete Deep Beams with Waste Plastic Fiber and Rehabilitated with CFRP Laminates

Abstract

In terms of recycling and reuse business, the amount of plastic waste accumulated in the world nowadays are more than those consumed as it is a non-biodegradable material. This problem leads to the accumulation of large stocks of toxic plastic waste, which affect on public health and increase safety risks. Therefore, it has been proposed to use plastic waste in the construction of various structural members as a step to tackle accumulation problem. In this regard, this research aims on investigating the structural behavior in terms of shear of reinforced concrete continuous deep beams incorporating Polyethylene Terephthalate (PET). Indeed, and by following up the sustainability concept, various strengthening techniques were suggested to strengthen the pre-partially damaged reinforced concrete continuous deep beams by carbon fiber reinforced polymer (CFRP).
For this purpose, several tests were conducted using cubes and cylinders to investigate the influence of various volume fractions of Polyethylene (i.e. 0.5,1 and 1.5%) trephthalate (PET) fibers on the mechanical properties of concrete such as: workability, compressive strength and splitting tensile strength. Furthermore, the structural bahavior represented by shear resistance of RC continuous deep beams incorporating PET fibers were also investigated after been strengthened by CFRP at an angle (90° and 45°) as they initially designed with intended shear deficiencies. Twelve RC continuous deep beams have been designed to fail in shear with a length of (2000 mm), depth (300 mm), and width (150 mm). Four specimens with various PET fibers were tested to reach the shear failure and considered as references specimens. The remaining specimens were loaded up to (60%) of their designed load and then strengthened with CFRP sheets and tested later.
The results show the structural behavior of RC continuous deep beams with PET fiber exhibited better performance, finer failure cracks than those without fiber. Furthermore, the peak shear strength was recorded at sample with 1% fibers percentage as it recorded higher value by slight increase in comparison with that with no fiber. Furthermore, the experimental results illustrated that beams strengthened with CFRP sheets exhibited higher ultimate load capacity compared to the reference specimens. Likewise, the shear ductility increased by (33.42%) and (45.83%) with the increase in the fibers percentage until (1%) for beams strengthened by CFRP at 90° and 45°, respectively.