Experimental Investigation On Physio-Mechanical And Micro-Structural Properties Of High Volume Fly Ash Concrete Incorporating Molasses As An Admixture

Abstract

The Drive To Mitigate The Environmental Impact Of Concrete Production Has Spurred The Exploration Of Waste Materials As Partial Replacements For Cement. A Notable Candidate Is Fly Ash (Fa). Despite The Broad Based Research Carried Out Across The Globe In Utilizing Fa As A Cement Replacement Material In Concrete, The Level Of Replacement Is Still Limited To A Maximum Of 30% Of Cement By Mass With Significant Quantities Of Fa Still Not Utilized Globally. To Tackle This Challenge And Enhance Concrete Performance, The Concept Of High Volume Fly Ash Concrete (Hvfac) Has Emerged, Allowing For The Incorporation Of Up To 60% Fa. Addressing Both Environmental Concerns And Performance Optimization, This Study Investigates The Integration Of Sugarcane Molasses As An Admixture, Aiming To Refine The Formulation And Application Of Hvfac. Hence, In The Current Study, The Workability, Compressive Strength, Water Absorption, Microstructure, And Cost And Environmental Aspects Of C-30 Hvfa Concrete Blended With Sugarcane Molasses Were Investigated. To This Aim, Ten (10) Different Mixes Having Cement Replaced With 0%, 40%, 50% And 60% Of Fa Together With Varying Dosage Of Molasses (0%, 0.1%, 0.15%, And 0.2% By Mass Of Cement) For Each Percent Replacement Were Examined. The Test Results Indicated That With The Addition Of Fa And Molasses, The Normal Consistency Of The Mix Get Reduced And The Initial And Final Setting Times Were Also Prolonged For All Mix Scenarios. Furthermore, It Was Observed That A Fresh Concrete Mix Containing Hvfa And Cane Molasses Was More Workable Than Conventional Concrete .The Compressive Strength Test Results Of All Concrete Specimens Showed Significant Strength Reduction At 7-Day And 28-Day Age Against The Conventional Concrete. However, There Was Significant Increase In Strength From 28 To 56 Days Which Peaks 23.13% For 60% Fa And 0.2% Molasses Dosage. The Water Absorption Values Were Observed To Increase Linearly With Increase In Fa Content And Molasses Dosages At 28 Days Curing. However, Water Absorption Of Concrete Linearly Decreased As Curing Ages Increased From 28 Days To 56 (From 7.6% To 5.8%). Consequently, At 56 Days, Compared To Conventional Concrete, The Highest Reduction In Water Absorption Is 23.68% Which Was Obtained At A Mix Containing 60% Fa And 0.2% Molasses. Besides, The Microstructures Were Enhanced Because Of The Substitution Of 60% Fa And 0.2% Molasses. Moreover, The Mix Containing 60% Fa And 40% Cement Was Shown To Reduce The Consumption Of Non-Renewable Materials, Energy Consumption, Co2 Emissions, And The Cost Incurred For Cement By 16.64%, 44.20%, 58.58% And 41.97% Respectively Per M3Of Concrete Production.