International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online) Vol. 6, Issue 2, pp: (197-206), Month: October 2018 - March 2019, Available at: www.researchpublish.com
BEHAVIOR OF REINFORCED CONCRETE BEAMS WITH BASALT FIBERS ADDED TO THE MIX Nasr Z. Hassan1, Jehan Hassanin2 1
Assoc. Prof. of Concrete Structures Faculty of Eng., Mattaria, Helwan Univ 2
MSc Student, Civil Eng. Dept., Helwan University, Cairo, Egypt Corresponding Author E-mail: eng.jehan@hotmail.com
Abstract: Among the rapid development of fibers in the field of civil engineering, Basalt Fibers are new type of fibers recently introduced in the market. In this research eleven beams of M 25 grade of concrete with dimensions 150 mm width, 300 mm depth and 1800 mm support to support length were casted with the addition of basalt fibers (0%, 0.25%, 0.625% and 1%) from the concrete volume, to study the behavior of reinforced concrete beams with basalt fibers. The parameters studied were the percentage of basalt fibers, fiber locations and the reinforced ratio. Crack pattern, Load deflection curves, stiffness and load carrying capacity were investigated for each beam. From this study it was concluded that basalt fibers have positive effect on the behavior of under reinforced beams and can change the behavior of over reinforced beams to more ductile one. Keywords: Basalt Fiber, Concrete, Flexure Strength, Under Reinforced Beams, Over Reinforced Beams.
1. INTRODUCTION Concrete carry compression force and a small percentage of tension force, so when a beam is loaded and the tensile stresses at the bottom exceeds the tensile capacity of the concrete, cracks begins to propagate and the tension force will be resisted by the reinforcement. As known from the general properties of fibers concluded from different researches that adding fibers like steel fiber and glass fiber can contribute with steel reinforcement in carrying tension stresses induced in the tension zone if added to the mix in a certain limit, in addition to controlling cracks by its bridging action [1], [2]. This commonly used in under reinforced sections, while the effect of fibers in over reinforced sections is not taken into consideration in different researches due to the prohibition of different codes for using this type of section because the brittleness at failure without significant warning, However, using this type of section may be a solution if limited depth is provided. In this research under reinforced beams and over reinforced beams are been examined by adding basalt fibers (B.F) in the mix, a relatively new type of fibers, to estimate the amount of improvement that basalt fibers contribute in the behavior of both types.
2. LITERATURE REVIEW Md. Tabsheer Ahmed (2013), [3] tested cubes and beams with basalt fibers (0.25%, 0.5%, 0.75%, 1%) by the weight of cement, maximum increase in both compressive and flexural strength was reported at 1%. Tumadhir M. Borhan (2013), [4] tested concrete cubes with basalt fibers (0.1%, 0.2%, 0.3% and 0.5%) from the concrete volume at age 7,28 and 90 days. She concluded that maximum compressive strength was at 0.3%, while lower compressive strength was at 0.5% at different tested ages, she stated that this decrease may be due to poor areas of interface between the constituents as the
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