Chemical Stabilization of Expansive Sub-grade Soil Performance Evaluation on Selected Road Section in Northeastern Addis Ababa
| dc.contributor.advisor | Kumar, Tarun (PhD) | |
| dc.contributor.author | Solomon, Habtamu | |
| dc.date.accessioned | 2018-07-05T09:38:38Z | |
| dc.date.accessioned | 2023-11-09T14:09:24Z | |
| dc.date.available | 2018-07-05T09:38:38Z | |
| dc.date.available | 2023-11-09T14:09:24Z | |
| dc.date.issued | 2011-03 | |
| dc.description.abstract | Expansive soils are characterized by volume change due to variation in moisture content. The cyclic wetting and drying processes causes vertical movements in expansive soils and these movements lead to failure of pavements. These soils have very low load bearing capacity too when wet. These problematic expansive soils, therefore, when encountered as sub-grade should be avoided or treated properly. The removal of expansive soils and replacement with suitable fill material is an appropriate method in areas like Addis Ababa in most cases where there is suitable fill material available nearby. At places, however, its feasibility depends on the availability of suitable fill material within economic distances and the thickness of the poor sub-grade soil to be replaced. Chemical stabilization is another alternative being applied worldwide even if the method is at a conceiving stage in Ethiopia. In recent years there are tendencies to use lime and other chemicals to stabilize sub-grade and sub base materials by Ethiopian Road Authority (ERA) and Addis Ababa City Roads Authority (AACRA). In the present study, hence, the performance of a locally manufactured hydrated lime and an imported industry product Anyway Natural Soil Stabilizer (ANSS) were evaluated based on laboratory test results on expansive sub-grade soils collected from Gerji area. The sub-grade soil was first characterized based on Atterberg limits, linear shrinkage, CBR and percent swell of CBR. The test results showed that the sub-grade soil is classified as A-7-5 in the AASHTO and MH in USCS systems. These soils have very low load bearing capacity and are highly expansive nevertheless of the mineralogy of the sub-grade soil samples have no montimorillonite, as expected in such soils. Two soil layers on colour variations were observed in the field: the upper dark gray clay soil and the lower light gray clay soil. The effects of the chemicals were then evaluated on two soil samples. The improvement of the sub-grade soil samples increased with increasing both dosages as well as curing periods. In general terms, increasing the dosage has more significant effect than that of increasing the curing period and 4% of either chemical has resulted in adequate improvements of the subgrade soil. In most cases the performance of hydrated lime is better than that of ANSS and the improvement of the dark gray clay soil is better than the light gray clay soil. | en_US |
| dc.identifier.uri | http://10.90.10.223:4000/handle/123456789/6655 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa Universty | en_US |
| dc.subject | Expansive Soils | en_US |
| dc.title | Chemical Stabilization of Expansive Sub-grade Soil Performance Evaluation on Selected Road Section in Northeastern Addis Ababa | en_US |
| dc.type | Thesis | en_US |