COMPARATIVE STUDY OF THE EFFECT OF TREATED COIR FIBER AND NATURAL RUBBER MODIFIED BITUMEN ON OPEN GRADED FRICTION COURSE MIXES

Open Graded Friction Course (OGFC) is aporous, gap-graded as phaltic concrete mixture that contains a high percentage of interconnected air voids. These types of mixtures are also referred to as Permeable Friction Course (PFC). Generally, the OGFC pavement reduces hydroplaning, splash and spray, and improves roadway visibility and the skid resistance of pavement surface under wet weather conditions. This research gives the results of a study focusing on four different OGFC mixes prepared with PG 60/70 bitumen, PG 60/70 & coir fiber, Natural Rubber Modified Bitumen (NRMB) and NRMB & coir fiber. Surface treatment process was done onthe coir fiber to improve the properties like durability and temperature stability. Coir fiber was mainly used in this study to reduce the drain downloss of OGFC mix. Natural Rubber Modified Bitumen is widely used in south Kerala and a few studies were conducted on mixes prepared with it. Mix designs were performed according to the design procedure proposed by the National Center of Asphalt Technology (NCAT) for a range of 4.5?6.0 % bitumen content and 0.3% fibre dosage.