INVESTIGATING THE STRENGTH OF SELF COMPACTED CONCRETE BEAM REINFORCED WITH PLANTAIN BUNCH FIBRE

ABSTRACT 

One of the ways to increase the strength properties of concrete is adding fibre material into the concrete. While to reduce a noise in construction project, a self compacting concrete was a good choice in the project. This thesis presents a study into the strength properties of self compacting beam concrete using plantain bunch fibre. Mix proportion of 1:1.82:1.27with different fractions of fibre namely: 0.00%, 0.25%, 0.50% and 0.75% by weight of cement with water cement ratio of 0.6, with an aspect ratio of 100was used for all the mixes. 40 beams and cylinders of size 150mm×150mm×600mm and100mm diameter of height 200mm respectively were cast. Tests conducted were density, flexural strength, splitting tensile strength and toughness. For density, the control specimen was 2405.6kg/m3. There was reduction in density of 4.76% when 0.75%fibre content was added. Addition of fibres negatively affected the density. This may be attributed to the higher weight of fibre replaced the cement matrix of the concrete. Similar trend was recorded for flexural strength. Control specimen recorded the highest strength of 2.93MPa. There was reduction of 15% when 0.75%fibre content was added. Specimen with 0.50% fibre content recorded the highest flexural strength value. Though, there was an improvement of 5% in the splitting tensile strength when 0.50% of fibre is used in concrete when the tensile strength of the control specimen was 2.35MPa. The tensile strength increased up to 0.50% addition. This then started decreasing making 0.50% the optimum fibre content. For toughness, the control specimen was 33.67N/mm2. However, an increase of 18% when 0.50% fibre content and 0.60 water-cement ratio were used to produce the highest toughness. The results support the conclusion that adding fibres improves the tensile strength and toughness of self compacting beam concrete. It is recommended that 0.50% fibre content and 0.60 water cement ratio could be used for lightweight concrete especially for low-cost structures.