Chemical Accelerating Admixture Dosage Optimization And Effect On Concrete Properties With Different Cement Brands

Abstract

Concrete Is The Most Common Building Material That Is Used Prominently In The Construction Industry. To Achieve High Early Strength, The Use Of Chemical Accelerating Admixtures Is A Valuable Choice In Concrete Production. However, There Is A Lack Of Studies That Provide The Optimum Dosage Of Accelerating Admixture To Produce Desirable Properties In Concrete. Due To The Lack Of Optimum Dosage Of Accelerating Admixture There Are Incompatibility Problems Between Admixture And Different Brands Of Cement. In This Regard, This Study Aims To Determine The Optimum Dosage Of Chemical Accelerating Admixture And Its Effects On The Properties Of Fresh And Hardened Concrete With Different Brands Of Cement. This Experimental Study Was Performed On C40 Concrete Made With Derba, Dangote, And National Ordinary Portland Cements And Variable Dosage Range Of 0.5% To 3% Of Astm Type E High-Range Water-Reducing And Accelerating Admixture (Hrwraa) With Variable Water To Cement Ratios. Based On The Experimental Results, The Physical Properties Of Cements Vary With Cement Brands, With Dangote Cement Having A Higher Fineness (96.29%) Than Derba Cement (93.39%) And National Cement (95.09%). National Cement Has A Faster Initial (172.9min) And Final (250min) Setting Time Than Dangote And Derba Cements. The Optimum Dosage Of Hrwraa For Derba, Dangote, And National Cements Was 1.5%, 2%, And 1.5%, Respectively. As Dangote Cement Is Finer, It Needs More Hrwraa To Achieve The Optimum Values. At Optimum Dosage Of Hrwraa, The Slump Value Was Achieved 135mm,175mm And 125mm For Derba, Dangote, And National Cements, Respectively. At Optimum Dosage Of Hrwraa, Concrete Mixes With Derba, Dangote, And National Cements Have Achieved 7days Compressive Strength Of 48.89mpa, 50.67mpa And 48.48mpa Respectively. At Optimum Dosage, 7 Days Tensile Strength Of Control Mix Was Improved By 68.05%, 64.52% And 51.95% For Derba, Dangote, And National Cements, Respectively. Similarly, At The Age Of 28 Days, The Flexural Strength Of Control Mix Was Improved By 12.23%, 11.57%, 10.32% And Permeability Of The Control Mix Concrete Was Improved By 39.6%, 34.6% And 31.6% For Derba, Dangote, And National Cements, Respectively. However, The Application Of Hrwraa Has Shown An Increase In The Cost Of Concrete Mix, With National Cement Demanding A Higher Cost To Produce 1m3 Of Concrete Than Derba And Dangote Cements. Generally, Hrwraa Plays A Vital Role In Improving The Physical Properties, Mechanical Properties, And Durability Of Concrete. However, Overdoses Of Hrwraa Were Found To Reduce The Strength Of Concrete By Developing Higher Porosity Due To Bleeding And Segregation Occurrences.