Laboratory Investigation of Open-Graded Friction-Course Mixtures Containing Polymers and Cellulose Fibers

Abstract

Open-graded friction course (OGFC), which consists of an open gradation mostly of coarse size aggregate with little fines, is a special purpose mixture that is increasingly used in pavement surfacing around the world. The typical benefits of an OGFC mixture are increased surface permeability, noise reduction, and enhanced surface friction, especially in wet conditions. This paper presents results of a study focusing on the use and properties of OGFC mixtures containing reclaimed polyethylene modified binder (RPEB), crumb rubber modified binder (CRMB), and neat 60=70-grade binder with cellulose fibers. The relative performance of mixtures and an aspect relating to the design of such mixtures, based on the laboratory study, have been presented in detail. Several laboratory tests were carried out in this study to evaluate open-graded friction course mixture properties by adopting two different types of Marshall compaction. A draindown test, a Cantabro stone loss test, a permeability test, an indirect tensile strength test, a resilient modulus test, a rutting test, and a skid resistance test were used to evaluate the performance of OGFC mixtures. The addition of fiber stabilizers and polymerized asphalt significantly reduced the potential for draindown in OGFC mixtures. Mixtures compacted by 50 blows on one face by a Marshall hammer were found to give improved results with respect to abrasion and other related mixture properties of the OGFC mixtures. The test results indicated that polymer modi- fication of the binder enhances the relevant engineering properties of the OGFC mixtures. Tensile strength ratio (TSR) values were found to be less for mixtures with modified binders than the mixtures with unmodified binders and fibers. DOI: 10.1061/(ASCE)TE.1943-5436 .0000304. © 2012 American Society of Civil Engineers.