The Potential Use of Cinder as a Sub base Material When Blended with Fine Grained Soil (The Case of Durame Intercity Road Project

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Addis Ababa University


Soil stabilization is the process of improving the engineering properties of the soil and thus making it more stable. In the process of soil stabilization and modification or soil strengthening, emphasis is given for maximum utilization of local materials. In this study, cinder and fine grained soil were blended to be used as sub base material. The research is basically conducted based on the available cinder gravel and fine grained soil found in Durame area. The significance of the study is to provide alternative material for road construction, specifically for road sub base construction. The objective of this study is to investigate the strength characteristics of mechanically stabilized cinder to be used as sub base material. An attempt has been made in this study to evaluate the potential use of cinder gravel as sub base material when blended with fine grained soil. Accordingly, to achieve the Ethiopia Road Authority manual specification, the cinder gravel was blended with some trail proportion of 0, 10, 20 and 33 % of fine-grained soil by dry weight. In this study the conducted tests includes gradation, compaction test, atterberg limits, free swell, specific gravity, and California Bearing Ratio test. Laboratory test results showed that the optimum amount of fine grained soil required to achieve the ERA manual standard specification requirement was found to be 20 %. Laboratory tests conducted on specimen prepared using the optimum amount of fine grained soils revealed that cinder gravel responded very well to the fine grained soil treatment, as exhibited in improvement of its gradation and plasticity. From the laboratory test results of moisture content vs. density relationship, it has been observed that the optimum amount of fine grained soil is 20 % by weight proportion at a density of 1.87 g/cc, the range of soaked CBR of the blended mix increases from 64 % to 97 % and PI value from zero to 0 % to 6.1 %.



CBR, Cinder Gravel, Compaction, Gradation, Sub base, Optimum fine- grained soil Content