Assessment of the Cause and Effect of Early Damage of Cobble Stone Road Construction and Its Remedial Measurements: A Case of Nekemte Town Cheleleki Sub City

Abstract

Road constructing in Ethiopia is increasingly in demand to meet its medium and long term development programs. Most internal roads of Oromia city/town are cobblestone and gravel. Some portions along the alignment proposed and existing roads traversed low resistance of the subgrade that affect the stability of the upper layers of cobblestones. Structural failure is observed on cobblestone roads, and it would be constructed with good quality or low quality of materials. Nekemte Cobblestones Projects have been started in 2014 widely which were filled in most areas today as we observed that needs to be addressed and a corresponding remedial measures must be drawn. A possible counteractive actions had been ordered for every observed destroyed to achieve the standard road situation of the study zone. An evaluation was made use observation, interviews, laboratory test and field test to govern an appropriateness of cobblestones. The lie beneath soil used for bottom layers of road structure based on standard of Ethiopian Road Authority (ERA) low volume road standards. Therefore, result from the field test and laboratory test shown, causes of cobblestone road failures of Nekemte street segment were mostly because of the construction steps/sequence, quality of materials, road construction time, absence of appropriate design, quality supervisor, absences of drainage structures, lack of highly compaction, lack of accurately fill fine aggregate and suddenly high loads vehicle applied on cobblestone road.