Improving The Performance Of Hollow Concrete Block Through The Use Of Alternative Aggregate: The Case Of Adama Town Ethiopia

Abstract

Conventionally, Hollow Concrete Block (Hcb) Is Produced From Ordinary Portland Cement (Opc) And Pumice Aggregate In Adama Town-Ethiopia. This Study Aims To Improve The Performance Of Conventional Hollow Concrete Blocks Through The Use Of Alternative Aggregate (Pumice-Scoria Blend). A Two-Phased Experimental Study Was Conducted Where Initially The Physical Properties Of The Two Aggregates Were Tested And An Appropriate Pumice-Scoria Blend Was Investigated. The Result From The First Phase Of The Study Showed That The Conventional Pumice Aggregate Is Poorly Graded, While The New Blend Containing 60% Coarser Pumice And 40% Finer Scoria (P60-S40) Is A Well-Graded Aggregate. In The Second Phase Of The Study, Two Groups Of Hcb Samples Were Produced Using Conventional And Blended Aggregates With 1:8 Cement To Aggregate And 1:6 Water To Cement Ratios. Samples Were Cured And Tested For Their Standard Properties At The Age Of 28 Days As Per Astm C140/C140m–20 Procedures. The Test Results Showed Compressive Strength, Density, And Water Absorption Of Conventional Blocks As 1.56 Mpa, 1066.60 Kg/M3, 26.17%, Respectively; Whereas The Corresponding Result For The Improved Block Was 3.51 Mpa, 1181.85 Kg/M3, And 20.57%. As Noted From The Result, The Use Of P60-S40 Improved The Compressive Strength Of Conventional Hcb By More Than 100%. And From The Result, It Can Be Concluded That Hcb Producers In Adama Town Can Improve The Strength Of The Conventional Hcb By Using P60-S40 Aggregate Instead Of The Poorly Graded Conventional Pumice Aggregate.