Abstract:
It is a major challenge for developing country like Ethiopia to provide and maintain
all roads of the country on a sustainable basis with the limited resources. For better
utilization of limited resources, it requires the usage of affordable and appropriate
low-cost road construction techniques for unpaved roads. One of the affordable and
appropriate low-cost road construction techniques for unpaved roads is water bound
macadam as surfacing materials, which has been widely used in many developing
countries.
The objective of this research was to investigate technical feasibility of Dire Dawa
water bound macadam surfacing material for unpaved roads. The research started
with verification of availability of water bound macadam surfacing material and
focused on investigation of physical and engineering properties by conducting
laboratory tests and the conclusions and recommendations were given by comparing
the laboratory test results with international standard manuals.
This research paper highlight on availability of water bound macadam surfacing
materials in the study area and presented findings of laboratory test results of
physical properties of coarse aggregate ( grain size analysis test result nominal size
of 50 mm and flakiness index test result of less than 20%), the engineering property
of coarse aggregate (los angels abrasion test result less than 30%), and physical
properties of natural river sand (grain size analysis more than 98% passing sieve size
5.6 mm, less than 1% passing 75microns, LL less than 20% and PI less than 6%).
The research paper finally compared the test results to international standard
manuals and concluded that the Dire Dawa water bound macadam surfacing
materials has the best quality of physical and engineering properties that feasible to
be used as surfacing material for unpaved roads. The research result report is
submitted to Department of civil engineering, Jimma Institute of Technology and
published on the Jimma institute of Technology journal.
