Abstract:
Roads are the integral part of the transport system. It is not only strategically important but also plays a vital role in economic and social development of any country. So the need of developing new road networks and maintaining the existing ones is the need of the day. To fill this demand, an efficient, vast and an extensive road network is required. So for this purpose, a huge amount of aggregate is required. Therefore, alternate aggregate sources need to be explored in addition to existing aggregate sources. Besides the depletion of existing quarries like Margalla quarry, it will protect the beautiful landscape of Islamabad. The aim of this research is to find the suitable and cheap aggregate at the local level in Dina (Jhelum District), rather transporting from other regions. This will ultimately reduce transportation costs as well as environmental hazards. Hot mix asphalt (HMA) pavements consist of a mixture of aggregates (about 95 percent) and an asphalt binder (about 5 percent). Thus for this purpose, Dina aggregates were brought according to the estimated material required for each test. The gradation and material properties affect almost all properties of aggregate. Thus, aggregate gradation was selected with great care. Similarly, aggregate testing were carried out according to ASTM, AASHTO and BS standards. The Crushing test, LA Abrasion test, Shape tests (Elongation index, Flakiness index and Angularity Number), Aggregate Impact test, Specific Gravity of coarse and fine aggregate, and water absorption of coarse aggregate were performed. Its results were analyzed and conformed to the required flexible pavement standards. For bituminous mix, Marshall Mix and Superpave Mix designs were carried out using NHA aggregate bend of class ‘A’. Using 19mm as the NMSG, two different Asphalt grades were used with the same blend, i.e. 60/70 and 80/100 penetration grade. The same grades of asphalt and same size of NMSG were used in the Superpave testing as well. Hence specimens were prepared and their volumetric properties were calculated using the standard formulae of Asphalt Institute. All the results were conformed to the AASHTO, ASTM and NHA standards. Evaluating the aggregate properties, by conducting different tests on aggregates and mix properties from Marshall Mix and Superpave Mix Design Methods. Thus we have concluded that Dina aggregates are suitable for HMA construction in Pakistan, for base course as well as wearing course.
