Stabilization Of Black Cotton Soil Treated With Induction Furnace Slag And Sawdust Ash (In Case Of Addis Ababa Cmc Area)

Abstract

This Research Evaluates The Combined Effect Of Sawdust Ash And Induction Furnace Slag On Index And Engineering Properties Of Black Cotton Soils Which Are Considered To Be Problematic Soils For Civil Engineering Purposes. Black Cotton Soils Were Collected From Two Different Locations In Addis Ababa Around Cmc Area For Investigation Through Laboratory Testing. Sawdust And In Diction Furnace Slag Were Collected From Philipos Timber Industry, Kolfe Keranio Sub City And Ethiopian Iron And Steel Factory Respectively. The Sawdust Ash Was Mixed With Black Cotton Soil In Varying Proportions Of 4 %, 8 %,And 12 %, And The Characteristics Of Which Have Been Executed In The Laboratory. As A Result Of Which An Optimum Amount Of Sawdust Ash Was Determined Based On California Bearing Ratio (Cbr) And Unconfined Compressive Strength (Ucs) Values. Since The Trial Mixes Showed That The Use Of 8 % Sawdust Ash Gave Better Results, Thus The Black Cotton Soil Treated With Optimum Sawdust Ash Content Of 8 % Was Further Stabilized With 5%, 10 %, 15 %, And 20 % Induction Furnace Slag. Reduction In Liquid Limit And Plasticity Index, As Well As Optimum Increase In Cbr And Ucs Values, Which Were About 178% And 157% Increment In Cbr Values And About 40% And 26% Increment In Ucs Values, Was Achieved When Black Cotton Soils Of The First And The Second Locations Were Treated With 8% Sawdust And 10 % Induction Furnace Slag Respectively. Based On The Cost Comparison Done Between The Optimum Mix And Mass Replacement Method, The Quantitative Unit Cost Of Black Cotton Soil + 8% Sawdust Ash + 10% Induction Furnace Slag Was 5,287,661.39Birr/Km And The Quantitative Unit Cost Of Non-Expansive Soil Was 4,425,051.19 Birr/Km. Stabilizing The Black Cotton Soil Found To Be Economical Than Replacing The Black Cotton Soil With Other Non-Expansive Material With A Saving Cost Of About 16 %. It Was Thus Concluded That Treating Black Cotton Soil With Sawdust Ash And Induction Furnace Slag Enhances Its Strength And Gives An Economical Way Of Stabilizing Black Cotton Soil