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Shear Capacity of Fiber Reinforced Lightweight Concrete
El Shazly, Mariam Hesham
El Shazly, Mariam Hesham
Date
2018-11
Author
Advisor
Type
Thesis
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Description
A Master of Science thesis in Civil Engineering by Mariam Hesham El Shazly entitled, “Shear Capacity of Fiber Reinforced Lightweight Concrete”, submitted in November 2018. Thesis advisor is Dr. Sherif Yehia. Soft and hard copy available.
Abstract
In this study, shear capacity of fiber reinforced High-strength Lightweight Self Consolidated Concrete (HSLWSCC) was investigated. Lightweight aggregate, size 4- 8 mm coarse aggregate, was utilized in the evaluation. Steel (3D and 5D), synthetic and hybrid fibers (mix of steel (5D) and synthetic fibers) with a volume fraction of 0.75 % were added to the concrete matrix to prepare eight beams. In addition, four beams were prepared without fibers as control specimens. The twelve beams were prepared to cover the following six categories: 1) lightweight concrete (ALWSCC); 2) lightweight with partial normal-weight coarse-aggregate replacement (PRLWSCC); 3) lightweight with partial replacement and 3D steel fiber; 4) lightweight with partial replacement and 5D steel fiber; 5) lightweight with partial replacement and synthetic fiber; and 6) lightweight with partial replacement and hybrid fibers (mix of steel (5D) and synthetic fibers). The aim of the experimental program was to evaluate the effect of: 1) the normal-weight coarse-aggregate replacement; 2) the addition of fibers and 3) the steel fiber configuration on the shear capacity of lightweight concrete. It was concluded that the 12% replacement ratio of normal weight aggregate has insignificant effect on the shear capacity of the ALWSCC beams. The addition of the fibers showed a great enhancement in the ultimate load in the range of 91.6% to 137% compared to that of the control specimens (PRLWSCC). Furthermore, the fiber reinforced concrete beams showed improved crack distribution, post cracking and ductile behavior. The improvement was influenced by the fiber type and configuration. The experimental results of the four control beams were compared to the corresponding predicted values from the American, the Canadian and the European codes. It was concluded that, the Euro code, followed by the Canadian code, are better matching the experimental results in this investigation as compared to the ACI code. Moreover, the results of the fiber-reinforced beams were compared with the predicted values calculated from the ACI modified equation and previously proposed equations by other researchers, that accounts for the fiber effect. It was found that the ACI modified equation best matches the experimental results of the fiber reinforced concrete beams.