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
