Research On The Usage Of Rubberized Asphalt In Mongolia

The rising number of motor vehicles in industrialized and developing nations generates millions of used tires annually.Approximately 1.4 billion tires are sold globally each year.These tires are among the biggest and most problematic sources of waste due to the large production volume and limited durability.Many research projects and field applications have proven that the addition of a crumb rubber modifier to asphalt/bitumen to be an effective method of improving the performance grade of asphalt and enhance its properties.This also provides an environmental-friendly option for the disposal of the scrap tires.In this research,crumb rubber is used to investigate the potential to enhance the properties of asphalt mixture.The study aims,among other things,to investigate the effect of adding different percentages of crumb rubber on the properties of asphalt mix in comparison with local and international requirements.The study also aims to identify the optimum percentage in weight of crumb rubber to be added in the hot mix asphalt.Crumb Rubber(0.6 mm)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,(30)samples were prepared,12 samples were used to determine the OBC and the remaining were used to investigate the effects adding different Crumb Rubber percentages to asphalt mix.The OBC was 5.4 % by weight of asphalt mix.Four percentages of Crumb Rubber by weight of bitumen as aggregate of mix were tested(10,15,20,25 and 30%),besides testing of ordinary asphalt mix.Tests include the determination of stability,bulk density,flow and air voids.Results indicated that Crumb Rubber can be conveniently used as a modifier for asphalt mixes to improve performance of some asphalt mix properties.Crumb Rubber content of 17 %by weight of bitumen is recommended as the optimum Crumb Rubber content.Asphalt mix modified with 17 % Crumb Rubber by weight of bitumen meet the requirements of local and international specifications.The study recommends that further studies are needed,and that required to establish Mongolian standard for modified asphalt mixes.