EVALUATION OF FLEXIBLE PAVEMENT CONDITION; A CASE STUDY OF ISIOLO- MERILE RIVER ROAD (A2)

Abstract:
The purpose of this study was to evaluate condition of a section of IsioloMerile River Road (A2)
which is part of the Northern Corridor. In this report, findings of the pavement condition survey
such as structural adequacy assessments, surface distress survey, pavement roughness and traffic
volume are presented.
Structural adequacy was assessed using Falling Weight Deflectometre (FWD) in the field to
determine strength characteristics of pavement layers.Analysis of the deflection data obtained
using FWD shows that the material properties are within acceptable range and the pavement is
structurally adequate to sustain existing and future traffic loading up to the design life. However,
for the pavement to reach its design life, observed surface surface distress must be addressed.
Surface distress survey was conducted by visual observations and measurements to determine
the severity and density of observed distresses. The dominant surface distresses observed
comprise of longitudinal wheel path cracks, edge cracking, traverse cracking, raveling and
rutting. They have varying severity and density levels at various sections.. The potential causes
of the above surface distresses might be attributed to by inadequate bonding during construction,
insufficient shoulder support, poor compaction and poor adhesion of aggregates due to
insufficient asphalt content. However, the road can be considered as GOOD in terms of surface
condition rating.
Pavements deteriorate over time due to the action of traffic and environmental factors.
Consequently, they must be maintained or rehabilitated regularly to keep them in good condition
and ensure they have structural adequacy to perform throughout their design life.

 

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