Stabilization of Expansive Soil Using Bottom Ash (The Case of Gellan Town)

Abstract

Expansive (Black Cotton) Soil Is A Worldwide Problem For Civil Engineers It Causes Damages To Foundations And Pavements Due To The Uplift Pressure And Cracking Because Of The Presence Of Excess Montmorillonite In The Soil. Many Researchers Are Tried To Improve The Geotechnical Properties Of Expansive Soil To Reduce Problems Associated With Expansive Soil Using Stabilization Of Soil With Different Types Of Additives. The Main Objective Of The Present Research Work Aimed To Investigate Whether Or Not Bottom Ash Is Used As A Stabilizing Material For Expansive Soil. The Bottom Ash Was Previously Collected From Reppi ?Koshe Waste To Electric Energy Production Plant And The Expansive Soil Was Collected From Gellan Town Near Ethiopian Electric Power (EEP) Substation. The Proposed Samples Are Prepared With Different Proportions From Observed Published Papers As 5%, 10%, 15%, 20%, 25% And 30% By Weight Which Were Used For Laboratory Tests Such As Grain Size Distribution, Specific Gravity Which Both Samples Passed Through Sieve No 10 (2mm), Atterberg Limit Test, Samples Passed Through Sieve No 40 (0.425mm) Where Distilled Water Were Used For These Testes. Soaked California Bearing Ratio (CBR %), California Bearing Ratio Swell (CBR Swell %), Compaction And Unconfined Compressive Strength (UCS) All Samples Passed Through Sieve No 4 (4.75mm) And The Water Utilized Was From The Optimum Moisture Content Test Result For CBR (%), CBR Swell (%) And UCS Laboratory Tests. The Black Cotton Soil Was Initially Characterized On Index Property Tests And Found To Be A-7-5, OH According To AASHTO And USCS Soil Classification System Respectively Which Implies Exceedingly Expansive And Have A Poor Load Bearing Capacity. Plasticity Index, Optimum Moisture Content (OMC), California Bearing Ratio Swell (CBR Swell) Decreased With Increment Of Bottom Ash. California Bearing Ratio (CBR), Maximum Dry Density (MDD) And Unconfined Compressive Strength (UCS) Increased When Percent Of Bottom Ash Increased. There Was A Significant Improvement In The Properties Of Black Cotton Soil For CBR And CBR Swell But It Doesn?�?T Meet The Minimum Value Of ERA Specification For Sub-Grade And There Was A Good Achievement In UCS Which Can Be Used As Backfill Material For Retaining Wall And Other Small Structures By Comparative Study Of The Design Load. However Further? ?Investigation Was Needed To Use Potentially Available By-Product.