Determinants Of Family Planning Practice In Ethiopia

Expansive soils are characterized by volume change due to variation in moisture content. The cyclicrnwetting and drying process causes vertical and horizontal movement in expansive soils leading to failurernof civil engineering structures found on such soils. The problematic nature of such soils can be improvedrnby employing chemical stabilization techniques such as lime, cement and enzyme stabilization. However,rnas these techniques are expensive to developing countries such as Ethiopia, locally available low costrnmaterials can be applied as alternative to improve the engineering properties of expansive soils.rnIn the present research work, the performance of marble dust to improve the problematic nature ofrnexpansive soils is investigated. The study is carried out on a highly expansive soil section of selected roadrnproject. The natural subgrade soil obtained from the highly expansive section of the road is characterizedrnfor its engineering and strength properties and it is found to be highly expansive soil with low bearingrncapacity, high swell and characterized as A-7-5 according to the AASHTO classification and rated asrnpoor (unsuitable) subgrade material.rnThe expansive subgrade soil is blended with increasing percentage by weight (5% to 30%) and thernimprovements in engineering properties are studied and it is noted that it improves with increasingrnpercentage of marble dust and with increased periods of curing though it is not significant as compared tornspecification requirements of several standards.rnWith the higher percentage of marble dust (30%), the swelling potential of the natural soil changed fromrn‘High’ to ‘Medium’, LL reduced from 88% to 63%, PI reduced from 52% to 34%, CBR increased fromrn0.9% to 2.25% and the CBR swell reduced from 8.6% to 5.3%.rnUn-soaked CBR test is conducted on the natural subgrade soil and the 30% marble dust blended samplernand it has been noted that the subgrade class improves for both indicating significant reduction in projectrncost as result of reduction in pavement thickness.rnThus, marble dust can be recommended as an alternative stabilizing agent for expansive soils by itself orrnbeing blended with small percentage (1-3%) of effective stabilizing agents such as lime so that significantrnproject cost reduction and minimal environmental degradation can be assured.

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