Studying the Effect of Adding Glass Fiber on the Mechanical Properties of Asphalt Mixtures (Wearing Course Layer)

Abstract

As the modern highway transportation has high speed, high traffic density and heavy load, bituminous concrete pavements are subjected to various types of distress such as fatigue cracking, rutting and raveling. Modification of the asphalt binder is one approach taken to improve pavement performance. Generally, fibers and polymers are two important materials used for this purpose. It is thought that the addition of glass fibers to asphalt mixtures enhances material strength and fatigue characteristics. In this research, Glass Fiber are used to investigate the potential prospects to enhance asphalt mixture properties. Study aims include studying the effect of adding different percentages of Glass Fiber on the properties of asphalt mix comparing it with the local and international requirements, besides identifying the optimum percent of Glass fiber to be added in the hot mix asphalt. Glass fiber (12mm) were added to the asphalt mixture. Marshal mix design procedure was used, first to determine the Optimum Bitumen Content (OBC) and then further to test the modified mixture properties. In total, (33) samples were prepared, 12 samples were used to determine the OBC and the remaining were used to investigate the effects adding different Glass fiber percentages to asphalt mix. The OBC was 5.4 % by the total weight of asphalt mix. Six proportions of Glass fiber by the total weight of mix were tested (0.1, 0.2, 0.4, 0.6, 0.8 and 1%), besides testing of ordinary asphalt mix. Tests include the determination of stability, bulk density, flow and air voids. Results indicated that Glass fiber can be conveniently used as a modifier for asphalt mixes to improve performance of some asphalt mix properties. Glass fiber content of 0.27 % by the total weight of mix is recommended as the optimum Glass fiber content. Asphalt mix modified with 0.27 % Glass fiber meet the requirements of local and international specifications. Study recommends that further studies are needed in various types of fibers and others percent of bitumen. And its required to establish a Palestinian standard for the Modified asphalt mixes.