Abstract:
Surfacing material for gravel road construction should pass the required blended material
from the specification. Coarse aggregate and fine aggregate, as part of surfacing material,
should be in there intended and accepted gradation. The specification requires suitable
material in term of two basic soil parameters; namely shrinkage product and grading
coefficient which can be taken particle size distribution and linear shrinkage.
The general objective of this study was to evaluate the application of locally produced
gravel material for URRAP road construction. Laboratory experiment was done to check
the engineering properties of the gravel surfacing material. The result was compared with
ERA and AASHITO standard specification. Interview and observation were made to
determine the performance of the URRAP road.
Gravel material was taken from three quarry sites using random selection and select the
material which pass the graduation requirement. Out of the three sites, gravel from Chacha
was selected for further laboratory experiment.
The maximum dry density of the material was 1.632g/cc and optimum moisture content was
23.7%. The CBR test result was 49.0 percent and swell factor was found to be 0.2 percent.
The plasticity Index was 8.5, plastic product was 153.0 and Los Angeles Abrasion value
was 80.60 percent. +Other factors which are relevant on the design of gravel road was
taken also like rainfall data and traffic data which are 177.9 mm and 69veh/day. The cost
comparison was made for gravel surfacing material and macadam pavement which is found
to be 23,6000birr and 4M birr respectively.
It was found out that the localy produced gravel was partially suitable for gravel surfacing
material as compared with ERA and AASTHO specification because 75 percent pass the
required specification. All results pass except the LAA value and plasticity product. With
regard to economical aspect, in rural road construction, gravel road is preferable.
It was recommended the applicability of the locally produced gravel for URRAP road
construction. In this way it can help the local community reduce the unemployment and
help the local government increase their income. It was also suggested to perform
stabilization to improve the LAA value and plasticity product
