Dopravní stavby - Fakulta stavební - Vysoké učení technické v Brně

12th International Scientific Conference, April 20-22, 2009 Brno, Czech Republic 119POLYPROPYLENE FIBER MODIFICATION: A NEWAPPROACH TO THE SOLUTION OF RUTTING,FLUSHING AND BLEEDING PROBLEMS MONITOREDIN FLEXIBLE PAVEMENTSSerkan Tapkın, Ün Uşar, Ahmet Tuncan, Mustafa TuncanIn this study, different polypropylene (PP) fibers are utilised in order to determine the optimumbitumen content and the optimal PP dosage. The same optimum bitumen content of 5.0% wasutilized in all of the designs with or without PP. The most suitable PP, M-03 type, can be used at adosage of 3‰ by the weight of the aggregates. The conclusion can be made that the lives of the PPmodified asphalt specimens under repeated creep loading at different loading patterns increased by5-12 times vs. control specimens. The repeated creep tests resulted in primary creep stage in caseof the PP modified specimens, while the control specimens reached their tertiary creep stages.From the stiffness point of view, the PP reinforcement is a very attractive solution for rutting.Besides, from the air voids point of view, the PP modified specimens can be a charming alternativefor flushing and bleeding problems.1. IntroductionFrom the beginning of seventies, much of research has been devoted to the study of permanentdeformation (aka rutting) in flexible pavements [1]. Rutting can result in the loss of pavementserviceability in case when cracking follows the formation of ruts and rapid deterioration ofpavement due to accumulation of water on the pavement surface.Universal Testing Machine (UTM-5P) can carry out static and repeated creep tests [2]. Staticand dynamic creep tests can be performed using the UTM-5P. Repeated creep is also a veryimportant phenomenon for asphalt concrete. In hot summer days, on climbing lanes, heavy vehicleswith full load impose a considerable amount of distress to the pavement. The combination of hotweather with significant axle loads and slow moving trucks create a serious problem. Pronouncedamounts of permanent deformation arise in the pavement structure, coupled with flushing andbleeding problems for the stated conditions. Also on straight road sections, because of the slowspeed of heavy vehicles, similar problems can be encountered.Experimental ProgramMarshall specimens were prepared utilizing 50 blows on each face. The standard 50/70penetration bitumen was utilised. Marshall stability and flow tests were done and repeated creeptests were carried out by using UTM-5P in order to find the rheological properties of asphaltconcrete.Serkan Tapkın, Ph.D., Faculty of Eng. and Arch., Civil Engineering Department, Eskişehir, TURKEY,serkan.tapkin@gmail.comÜn Uşar, Graduate student, in Faculty of Eng. and Arch., Civil Engineering Department, Eskişehir, TURKEYAhmet Tuncan, Ph.D., in Faculty of Eng. and Arch., Civil Engineering Department, Eskişehir, TURKEYMustafa Tuncan, Ph.D., in Faculty of Eng. and Arch., Civil Engineering Department Eskişehir, TURKEY.