Assessment of Road Failures in Rift Valley Zone for the Case of Awash - Meiso Road Project

Abstract

Road pavement failure can occur in any road section due to different reasons, which can be related to the material used, method of construction, served traffic, type and frequency of maintenance and others. Although one or more of these factors can be the cause of road section failure, it is necessary to assess the condition of the road at different time frame in order to identify which factor is responsible for the cause of the road section failure in particular location. This may help to provide an appropriate and timely maintenance to the road section to serve its design life. Thus, the aim of this thesis is to assess the current condition of Awash – Meiso road section. This road section is selected due to its importance for the country economy as an import and export road corridor. To achieve the aim of the research a visual condition survey by Visualization for Information Retrieval (VIZIR) method in accordance with the Ethiopian Roads Authority manual has been conducted. In addition to this, in order to assess the current subgrade condition laboratory test has been performed on samples brought from seven selected test pit locations on the road segment. The findings of the condition survey revealed that more than 75% the road section showed distress with different severity conditions on the road segment. Moreover, the subgrade investigation identified that two spots (i.e. TP-1 and TP-4) on the segment have low quality subgrade soil. From the analysis of the collected data, it can be concluded that the current distress on Awash – Meiso is mostly due to traffic load and age. Since the traffic analysis showed that the current traffic are very high as compared to the estimated traffic flow on the road section.