An Investigation on Premature Failure of Mardan Mill By Pass Road

Abstract

Country’s economic growth and development depends upon a good communication system. The main source of communication throughout the world is road network. Road network plays very important role and considered as the back bone in country’s infrastructure. Mardan By-Pass carries a major traffic load off from Mardan City as well as by pass the hustle of the city. It is therefore a very important route for cargo and public transport. Recently it was being over layed. But just after few months there were cracks and humps observed indicating the premature failure of the road. Our syndicate undertook the task to investigate the possible causes of premature failure realizing the importance of this road. Samples had been collected by core cutting from various locations within the road and then series of tests were performed including Sieve Analysis of Soil, Specific Gravity of Soil and Coarse Aggregate used in HMA, Modified Compaction Test, Los Angles Abrasion Test, Bitumen Content Test and Marshall Flow and Stability test etc. The report also investigates the number of passes of various major load carrying vehicles. A literature review has also being added for reference. The results which came forward were lesser thickness of Base Course, Non uniform thickness of HMA, low Bitumen Content, poor drainage and some other miscellaneous defects which collectively caused the road to fail. The Report concludes that it was poor workmanship, lack of proper calculations, Taking rough traffic volume estimates that eventually caused the detrimental effects on road. This report recommends that although damage was severe but was not on a major scale so proper patching should be done under proper supervision and skilled labour should be hired for the job