Document Type : Original Article
Authors
1
PhD student, Technical and Engineering Faculty, Civil Engineering Department, Qazvin Branch, Islamic Azad University, Qazvin, Iran
2
Assistant Professor, Technical and Engineering Faculty, Civil Engineering Department, Qazvin Branch, Islamic Azad University, Qazvin, Iran
3
Associate Professor, Technical and Engineering Faculty, Department of Civil Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran
10.22065/jsce.2024.424606.3268
Abstract
One of the common techniques for enhancing the strength of existing reinforced concrete bridge beams involves adding reinforcing elements to the lower section of the beam. In the recent years, the reinforcement of concrete bridge beams is developing with the installation of precast high performance fiber reinforced cement composites, in addition to Fiber-Reinforced Polymer (FRP) sheets or strips and placed rebars near the surface. This study explores both the mechanical properties of composite cement laminates and how the presence of polymer rebars impacts these laminates. To create specimens, a total of 45 mixing designs were utilized, incorporating fibers and consumable materials. For comparison purposes, the specimens underwent various tests including four-point bending test with dimensions measuring 25×125×500 and 25×125×1700 mm, three-point bending test with dimensions measuring 40×40×160 mm, direct tension test on 8 shaped briquettes and compressive strength tests on cubic shapes measuring 40 mm. The results indicated good compliance with both direct tension and bending tests. After evaluation, the most suitable design was determined to consist of 1.8% micro steel fibers, 0.5% polyvinyl alcohol fibers, 42 kilograms of quartz powder, 28.6 kilograms calcium carbonate particles and 482 kilograms of silica fume slurry, per cubic meter of mortar. To analyze the chosen specimen, we conducted direct tension test on dogbone-shaped specimen and compressive strength test on cubic specimen measuring 100 millimeters. Adding quartz powder has a positive impact on enhancing the energy absorption capability of the laminate specimens. The use of two polymer rebars with a diameter of 8 millimeters lead to 2.3 times increase in the flexural stress tolerance. No significant difference was observed between the flexural behavior of the precast laminate under cyclic loading and the monotonic loading.
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