Browsing by Author "Karubanga, Adolph"

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Effect of banana fibers on the mechanical and microstructural properties of concrete
(Kyambogo university (unpublished work), 2021-08) Karubanga, Adolph
This research presents an experimental study on the "Effect of Banana fibres on the mechanical and microstructural properties of concrete". Concrete being a quasi-brittle material, exhibits limited ability to restrict and reduce the generation and development of cracks. Recently, Natural fibres with their principal raw materials being agricultural wastes were found to be one of the suitable alternative cementitious reinforcing material. The main objective of this research was to study the effect of Banana fibres on the mechanical and microstructural properties of concrete; and the specific focus was four-fold: Properties of banana fibres; properties of plain and Banana fibre reinforced concrete (BFRC) in hardened state; and finally, behaviour of fibres in concrete. A total of288 samples (cubes, beams and cylinders) ofC20/25 concrete mix comprising of six (06) mixes for plain concrete (reference concrete) and BFRC, were cast and tested in the laboratory at 14 and 28 days and the.behaviour of fibres in concrete modelled using ABAQUS computer software. BFRC had two parameters that were varied; fibre length (40 mm, 50 mm and 60 mm) and fibre content (0 .00%, 0.1 0%, 0.25%, 1.00%, 1.50%, and 2.50%). Findings revealed the following; the tensile strength of banana fibres was 167. 89MPa; samples containing banana fibres significantly impacted on the flexural and compressive strengths of concrete by 10 % and 13% respectively; while a residual strength of up to 40% for BFRC was obtained. The optimum fibre length was 40, and a lower fibre content of up to 0.25 % dosage. Further, samples containing fibres improved the microstructure of concrete; evidenced by a reduction in the interfacial transition zone of concrete (ITZ); no micro-cracks; cement paste deposited on surfaces of fibres and fmally exhibited higher intensity than plain concrete. ABAQUS FEM predictions on the representative volume element (RVE) model using experimental test results revealed that samples containing fibers were able to resist failure compared to plain concrete for both tension and compression failure conditions. It was therefore concluded that the incorporation of Banana fibers in concrete was found to improve on concrete properties at lower fibre content and fibre length.
Impact of addition of banana fibres at varying fibre length and content on mechanical and microstructural properties of concrete
(Hindawi: Advances in Civil Engineering, 2021-10-08) Mugume, Rodgers B.; Karubanga, Adolph; Kyakula, Michael
'is experimental study aimed at investigating the impact of addition of banana fibres on the mechanical (compression, splitting tension, and flexure) and microstructural (microscopic morphology and Energy Dispersive X-ray Spectroscopy) properties of concrete. Concrete mixes comprising of banana fibres of varying fibre lengths (40, 50, and 60 mm) and fibre contents (0.1, 0.2, 1.0, 1.5, and 2.5%) were assessed. Addition of banana fibres to concrete was observed to significantly impact on compressive strength only at lower fibre contents of up to 0.25% for all fibre lengths. Fibre length had no significant impact on compressive strength at lower fibre contents of up to 0.25%, but shorter fibres were observed to perform better than longer ones at higher dosages more than 0.25%. Increase in fibre content positively impacted on tensile strength of concrete at relatively lower fibre dosages of up to 1%. Similarly, fibre length impacted on tensile strength of concrete at lower fibre contents of up to 1% and, longer fibres were observed to be more effective than shorter ones. Addition of banana fibres generally did not greatly contribute to flexural strength of concrete but had a marginal impact only when shorter fibres were used at lower fibre dosages. Also, microstructure of concrete was improved through better bonding between the fibres and the matrix and reduction in porosity of the matrix, which resulted in improved mechanical properties of the composite. Banana fibres further contributed to changes in phases of the composite structure of Banana fibre-reinforced concrete (BFRC) through a reduction in its interplanar spacing and lattice structure. For optimal purposes, addition of banana fibres should be limited to a maximum of 1% fibre content preferably using shorter fibre lengths. Further research to improve flexural strength of BFRC to meet minimum technical requirements is required before it can be considered for structural applications