Plain Concrete Research Papers - Academia.edu (original) (raw)

In this study, jute fiber was used as fibrous material in concrete to improve the overall strength. Jute fiber of different lengths and percentages were selected. Three percentages of jute fibers were implemented here, such as 0.1%, 0.25% and 0.5% of the volume of plain concrete. Again, three lengths of jute fiber were selected such as 10 mm, 15 mm and 20 mm for each percentage to find out the best potential percentage along with length. All these were done to compare the compressive strength and split tensile strength of jute fiber reinforce concrete (JFRC) with plain concrete to find out the best results. Total 30 numbers of cube were prepared for compressive strength tests and 30 numbers of cylinder for split tensile strength tests. They were loaded in 7, 14 and 28 days respectively and the strengths were noted and compared with each other. The cube has shown maximum improvement over compressive strength for 0.25% jute fiber of 10 mm length. The compressive strength was increased by 22.51%, 29.56% and 26.15% for 7, 14, and 28 days respectively compared to plain concrete. The cylinder also has shown maximum enhancement over split tensile strength for 0.25% jute fiber of 10 mm length. The split tensile strength was increased by 14.09%, 26.23% and 25.48% for 7, 14, and 28 days respectively compared to plain concrete. Here, the improvement was little for 0.1% jute fiber compared to 0.25%. However, the strengths has been dramatically reduced for 0.5%.

- by and +1
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- Concrete, Compressive Strength, Plain Concrete, Jute Fiber

It was shown by the authors [3], [4], how the powerful numerical techniques such as Finite Element Method (FEM) and Boundary Element Method (BEM) could be applied to solve some problems of the Linear Elastic Fracture Mechanics (LEFM). The structural material considered was presumed ideally brittle, such as ceramic or glass. A small inelastic process zone in front of the crack tip was also included in the solution, using the idea of the first and second Irwin’s corrections.

- by Irina Kerelezova
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- Fracture Mechanics, Plain Concrete

A Visual Basic for Application’s program for calculating crack growth in concrete and reinforced concrete beams is presented in this paper. This program is useful for obtaining quick results for initial analysis and parametric study. In the present program Nielsen’s crack growth formula is incorporated which is a new and original effective crack model. Some results are presented and comparisons with experiments are performed.

- by Irina Kerelezova
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- Fracture Mechanics, Microsoft Excel, Plain Concrete

The objective·• of the present paper is to introduce a finite element model performing a nonlinear numerical analysis on concrete structures with different sizes. The cohesive crack method of Hillerborg is employed, which can be also found in literature under the name fictitious crack method. For mode 1 cracking, the present model is capable of predicting the behavior of the whole range of structural sizes, including the extreme cases of the limit analysis and linear elastic fracture analysis. The numerical simulation for large concrete structures shows a good coincidence with LEFM model. The inclusion of small nonlinear zone in front of the crack tip, based on Irwin's correction procedure, is also discussed and comparisons are made. A special form of the brittleness number is used in order to reveal the strong size effect of the structures with different sizes or/and
different fracture mechanics parameters.

- by Irina Kerelezova
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- Fracture Mechanics, Plain Concrete

The research aims to develop an innovative technique for segmental beam fabrication using plain concrete blocks and externally bonded Carbon Fiber Reinforced Polymers Laminates (CFRP) as a main flexural reinforcement. Six beams designed and tested under two-point loadings. Several parameters included in the fabrication of segmental beam were studied such as; bonding length of carbon fiber reinforced polymers, the surface-to-surface condition of concrete segments, interface condition of the bonding surface and thickness of epoxy resin layers. Test results of the segmental beams specimens compared with that gained from testing reinforced concrete beam have similar dimensions for validations. The results display the effectiveness of the developed fabrication method of segmental beams. The modified design procedure for externally bonded carbon fiber reinforced polymers ACI 440.2R-17 was developed for designing segmental beams. The experimental test values also compared with design values, and it was 93.3% and 105.8% of the design values, which indicates the effectiveness of the developed procedure.