Title: Effect of Synthetic Fibers on Shear Capacity of Reinforced Rubberized Concrete Beams

Author(s): Basem H. AbdelAleem, Mohamed K. Ismail, and Assem A. A. Hassan

Publication: Materials Journal

Volume: 115

Issue: 2

Appears on pages(s): 279-288

Keywords: crumb rubber; large-scale reinforced concrete beams; selfconsolidating and vibrated concretes; shear behavior; synthetic fibers

DOI: 10.14359/51701123

Date: 3/1/2018

Abstract:
This paper investigates the combined effect of crumb rubber (CR) and microsynthetic/macrosynthetic fibers on the shear behavior of reinforced concrete beams. Twelve large-scale self-consolidating and vibrated concrete beams were constructed with varied percentages of CR (0 to 30%) and different types and volumes (0, 0.2, and 1%) of synthetic fibers. The tested fibers included microsynthetic fibers (MISFs) 19 mm (0.75 in.) in length (MISF19) and macro-synthetic fibers (MASFs) of various lengths: 38 mm (1.5 in.) (MASF38); 50 mm (1.97 in.) (MASF50); and 54 mm (2.13 in.) (MASF54). The experimental results indicated that the inclusion of CR negatively affected the ultimate shear load, post-diagonal cracking resistance, energy absorption, and first cracking moment of the tested beams while it improved the deformation capacity, self-weight, and cracking pattern. Combining CR with MISFs or MASFs (especially MASF38 and MASF50) further improved the deformation capacity, selfweight, and narrowed the crack widths of tested beams. The results also indicated that the use of a relatively higher percentage of fibers (1% compared to 0.2%) in vibrated rubberized concrete beams significantly compensated for the reduction in shear strength resulting from a high CR replacement of 30%. Noticeable increases in the deformation capacity, post-diagonal cracking resistance, and energy absorption capacity were also achieved in vibrated rubberized beams, especially when MASF38 and MASF54 were used.