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IJERTV9IS020136
Assessing the Performance of Subgrade and Unbounded Pavement Materials and Their Effect on Pavement Distress of Alaba-Sodo Exisiting Road; Ethiopia
Defaru Katise , Nazrawit Aklilu , Dr. Ramesh Kumar Verma
Since material properties play a significant role to determine the performance of pavement layers. In Ethiopia, now a day, pavement distress is the main problem of roads affecting its intended purposes. This research study is undertaken at Alaba-Sodo road, which is located in SNNPRS, is one of the roads affected by distresses. The main objective of this study is to assess the performance of subgrade and unbound pavement materials and their effect on pavement distress through condition survey and laboratory tests.
Among the total sample units of 199 along the selected road sections, 71 sample units were selected by using systematic random sampling technique. For those selected sample units PCI values were determined in order to know the stations for sample collection for laboratory tests. Based on the PCI values, eight sample locations were identified out of these six locations were selected from severely distressed and two locations were selected from good sections. From eight identified sample locations three samples were taken from each layers of sub-grade, sub-base and base course. Therefore, total of 24 material samples were taken for the laboratory tests. The major tests such as CBR test, Compaction Test, Atterberg limit test, Sieve Analysis were conducted for the above mentioned three layers and ACV, AIV, LAA and Flakiness Index were conducted only for base course material to check performance of the pavement materials.
Out of the surveyed 71 sample units, 1.41% is excellent, 5.63 is very good, 14.08% is good, 23.94% is fair, 28.17% is poor, 21.13% is very poor and 5.63 is failed. The overall laboratory test result shows that the distresses that are frequently observed on the road surface were significantly influenced by subbase and base course materials.