International Journal of Recent Innovation in Engineering and Research Scientific Journal Impact Factor - 3.605 by SJIF e- ISSN: 2456 – 2084 @IJRIER-All rights Reserved -2017 Page 49 INFLUENCE OF LENGTHS AND VOLUME FRACTIONS OF FIBRE ON MECHANICAL PROPERTIES OF BANANA FIBRE REINFORCED CONCRETE Solomon Ikechukwu Anowai 1 and Olorunmeye Fredrick Job 2 1,2 Department of Building, University of Jos, Nigeria Abstract: This study investigates the mechanical properties of concrete reinforced with banana fibres at varying lengths and volume fractions. Grade 25 concrete specimens were reinforced with banana fibres of 10, 20, 30 and 40mm long. For each length, the fibres were introduced in volume fractions of 0.25, 0.5 and 1.0. The specimens were cast, cured in water upto 28 days. The mechanical properties such as compressive strength, flexural strength and splitting tensile strengths of the specimens were determined after 7and 28 days of curing. The results show that the variation in length and volume of banana fibre affects the mechanical properties of banana fibre reinforced concrete. The concrete mixture reinforced with banana fibres 30mm long and volume fraction of 0.5% achieved the highest compressive strength compared to all the specimens’ reinfordced with banana fibres. However the control plain concrete achieved a slightly higher compressive strength than all the specimens reinforced with banana fibre. Mixture reinforced with banana fibre of volume fraction, 0.5% and length of 30mm achieved the highest flexural strength of 6.25 N/mm 2 , which is 25% higher than the flexural strength of the control mix. The concrete specimen reinforced with 0.5% volume fraction of 30mm long banana fibres achieved the highest splitting tensile strength of 3.66 N/mm 2 , which is 27.97% higher than that of control mix which recorded a splitting tensile strength of 2.86 N/mm 2 . This recommends the use of 0.5% volume fraction and 30mm length of banana fibre in grade 25 concrete. Keywords - Banana fibre, concrete, length, influence, volume fraction, I. INTRODUCTION Plain concrete possesses a high compressive strength but low tensile strength. Cracks [1] develops in plain concretes even before loading due to drying shrinkage and other causes and when load is eventually applied the internal cracks propagate and open up due to stress and additional cracks are formed. According to [1] the addition of small closely spaced and uniformly dispersed fibres to concrete acts as crack arrester and improves its static and dynamic properties. Addition of fibres to concrete considerably improves its structural characteristics such as static flexural strength, tensile strength, ductility and flexural toughness [2]. Fibres in concrete according to [3] eliminate or lower down the shrinkage cracks developed and improve the flexural and splitting tensile strength of the concrete. Fibre cannot be used as conventional reinforcement but it can lower down the requirements of steel reinforcements [3]. To arrest the propagation of cracks steel reinforcements and fibres are usually introduced into concrete to resist the tensile stresses. Fibre reinforced concrete has been defined to be a Portland cement concrete reinforced with more or less randomly distributed fibres [4]. According to [5] fibre is a small piece of reinforcing material possessing certain characteristic properties and it could be circular, triangular or flat in cross-section. The introduction of fibres in concrete mix is not always for structural purposes in the same manner as in traditional steel reinforced concrete, although fibres increase tensile and shear strengths of concrete [6]. Fibres used for this purpose include fine chopped steel, polypropylene, nylon, Glass and Cellulose (natural fibres). Due to light weight, high strength to weight ratio, corrosion resistance and other advantages such as low cost and wide spread availability,