Evaluation of the Strength Properties of Asphalt Concrete using Natural Fibres as Reinforcing Additives

Abstract

The period of maintenance and rehabilitation of asphalt concrete pavement can be increased by using fibres as reinforcement in a bituminous mix. Shredded Sisal fibre (Agave sisalana) and Sponge gourd (Luffa cylindrical) were used as reinforcements in bituminous mix. The fibres were added to hot mix asphalt in varying proportion of 0.1%, 0.2%, 0.3%, 0.4% and 0.5% by weight. The strength of fibre reinforced asphalt concrete was determined by conducting Marshall stability test. The tensile strength on 40 strands of fibre gave 167.43 N/mm2 and 24.58 N/mm2 for Sisal fibre and sponge gourd fibre respectively. Marshall Stability test results indicated that Sisal fibre gave minimum and maximum values of 4.46 kN and 5.54 kN, respectively, which exceeded the 3.5 kN minimum stability value for wearing course in the Nigerian General Specification for Roads and Bridges. The flow values obtained showed that the flow values are more than the 4 mm minimum value except for 0.1 sisal fibre dosage which has a value of 3.99 mm. The high flow values obtained was an indication of the reinforcing effects of the fibres which made the asphalt concrete stronger and hence have great resistance to plastic deformation.