Assessing the impact of bitumen types on the Performance of asphalt concrete road pavement construction in Uganda

Abstract

This research was conducted to assess the impact of local asphalt binders on the performance of asphalt concrete road pavement construction in Uganda. The bitumen samples were collected from ongoing road construction projects where asphalt concrete made pan of the pavement. The sampling was done in accordance with procedures provided in BS EN 58: 2012 and BS EN 475: 2000. Testing was carried out in Central Materials Laboratory, Tan Roads. Dar Es Salaam, Tanzania to confirm binder classification and obtain performance properties. The penetration tests, fluidity and pumping tests conducted on the bitumen samples confirmed compliance with specifications. It was noted that all penetration grade bitumen samples gave softening points lower than the allowable limits implying in-service performance challenges. Most of the samples did not comply with physical property requirements when compared with the binder specifications implying that they arc susceptible to rutting and fatigue damage. Binder Temperature zoning based on Strategic Highway Research Program of asphalt grading system was completed in fourteen zones and presented on a map. Three temperature zones were confirmed incorporating Perfom1ance Grade (PG) 70+ 3 in most of the Northern, far Eastern and Kasese regions, PG 64+6 for most of Central and PG 58+3 for far Western regions bordering with Rwanda and Democratic Republic of Congo. This study introduced a robust testing regime and acceptance criteria to be used in future asphalt designation and construction in Uganda. Accordingly. value engineering was achieved based on increased time intervals of road