Shear Strength of Reinforced Fibrous-self Compacted Concrete Box Girder using Recycled Concrete Aggregate


Protection of environmental and conservation of natural resources is afundamental issue in today’s world. In this research, the shear behavior ofreinforced concrete box girders with recycled aggregate (RA), steel fiber, andinternal diaphragms were investigated. Eleven reinforced concrete box girderswith typical longitudinal and transverse reinforcement were tested under twopoint loading until failure. The RA was prepared by crushing the collected wasteof concrete from the laboratory test cylinders and cubes. The experimentalvariables considered include; RA percent of 50%, 75%, and 100%(replacingfrom NA), steel fiber with volumetric ratios (Vf) of 0.5%, 1.0%, and 2%,diaphragm numbers (two and three).The test results revealed that the shearstrength of the box girders affected by the RA content, the ultimate load wasdecreased by (32, 25, and 19) % for the (011, 75, and 01) %RA concrete,respectively in compared with the control specimen. In contrast the steel fiberwas more effective in strengthening of the RA concrete specimen, for the (Vf) of0.5%, 1.0%, and 2.0% with non-fibrous 100% RA concrete, the strengtheningwere (25, 40, and 77) % respectively. Moreover, when 1.0% steel fibers added tothe 011%, 75%, and 01%RA concrete respectively, the strengthening were (41,45 ,and48 )% compared each with its reference specimen. On the other hand,when two and three diaphragms used, the strengthening for the non-fibrous 100%RA concrete was (6% and 9%) respectively. cracking load, ultimate load, loaddeflection, and concrete surface strain has been taken into consideration in thisresearch.