Evaluation the Usage of Local Materials in HMA Surface Layer

Abstract

The importance of roads and all the facilities related to the mobility of people, goods, and vehicles in the world exceed the social and economic significance but play a main role in politics and government decisions. As a result of the increasing population in Iraq and the dramatical growth in heavy vehicles twenty years ago and due to the rising percentage of new construction projects in the country, the need appeared to assess and improve the hot mix asphalt layers used in the construction of flexible pavements. In this research, a hot mix asphalt surface layer was used with a 12.5 mm nominal maximum aggregate size from one aggregate source (Al Nibaie quarry) and one penetration grade type of asphalt binder (40 -50), also in this research work has been added one type of polymers by several percentages namely, Crumb Rubber Modifier (CRM) to enhance the properties of asphalt binder which in turn improves HMA. The evaluation process included the preparation of two types of mixtures (unmodified and modified mixtures) by using the Superpave mix design method and to estimate the ability of mixtures to resist the three main types of failure that may be flexible pavement exposed to, Wheel track test was used to simulate the permanent deformation resistance of mixtures, flexural beam fatigue test to determine the fatigue cracking resistance of mixtures and indirect Tensile Strength test was used to determine the strength to moisture damage for prepared mixtures. Results demonstrated that adding modified waste polymer to the asphalt cement with different percentages significantly improved mechanical and durability properties.