Browsing by Author "Nnabuihe, kingsley Ikechukwu"

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    Effects of fly ash and rice-husk ash on lime stabilization of expansive soils from Lokpaukwu and Awgu, Nigeria
    (Federal University of Technology, Owerri, 2018-10) Nnabuihe, kingsley Ikechukwu
    Soil stabilization refers to the technique of altering the properties of a soil so as to improve its engineering performance. It aims at using chemical additives such as lime as a lone stabilizer or in combination with industrial residues (fly ash, rice husk ash, etc) to achieve this fit. This work investigates the effects of lime alone, lime fly ash (LFA) and lime-rice husk ash (LRHA) blends in varying percentage mixtures on the engineering properties of expansive soils from Lokpaukwu (Ezeaku Formation) and Awgu (Awgu Formation) in Lower Benue Trough. The soils were stabilized with different percentages of lime (i.e. 2, 4, 6, 8, and 10%) and varying percentage ratio for lime-fly ash and lime-rice husk ash blends (i.e. 2 : 6, 2 : 8, 2.5:7.5, 2.5 : 10, 3 : 9, 3 : 12, 4 : 12, 4 : 16, 5 : 15 and 5:20).Liquid limit, plastic limit, linear shrinkage, compaction characteristics and California Bearing Ratio (CBR) tests were performed on the natural and lime-treated Lokpaukwu and Awgu soil samples while consistency limits and linear shrinkage tests only were performed on the lime-residue treated soil samples. Results of the study indicate that optimum reduction percentage of 24.14% and 30.56% (liquid limits), 72.22% and 74.42% (plasticity indices), 56.14% and 60.12% (linear shrinkages) and maximum percentage increase of 25.60 and 33.70 (Optimum Moisture Content (OMC)), 193.3 and 250 (unsoaked CBR), and 766 and 700 (soaked CBR) for Lokpaukwu and Awgu samples respectively were obtained on stabilizing the soils with 6% lime content. The results from lime-fly ash (LFA) and lime-rice husk ash (LRHA) blends indicate that liquid limits, plasticity indices and Linear Shrinkages decreased from 58 and 72 to 46 and 51, 36 and 43 to 11 and 12, 11.4 and 14.3 to 6.4 and 7.1, and from 58 and 72 to 45 and 51, 36 and 43 to 10 and 11, 11.4 and 14.3 to 6.4 and 7.1 for Lokpaukwu and Awgu samples respectively when treated with Lime-fly ash blend of 3 – 12% and lime-rice husk ash blend of 3 – 9%. It could be concluded that improving the characteristics of expansive soils by lime-fly ash blend or lime-rice husk ash blend is successful and provides immense environmental and economic benefits