Reduction of cement content using graded aggregates in concrete production

Benjamin Okwudili Mama Benjamin Okwudili Mama,Chinedu Christian Asogwa Chinedu Christian Asogwa,Samson Nnaemeka Ugwu Samson Nnaemeka Ugwu,Boniface Obi Ugwuishiwu Boniface Obi Ugwuishiwu

doi:10.30574/gjeta.2021.7.3.0083

Benjamin Okwudili Mama Benjamin Okwudili Mama, Chinedu Christian Asogwa Chinedu Christian Asogwa + Show 2 more

Open Access

https://doi.org/10.30574/gjeta.2021.7.3.0083

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Abstract

The aim of this project was to reduce cement content in concrete mixtures by changing the aggregate grading. For this purpose, concrete mixtures were made with aggregates having different shapes, textures, and grading. However, the workability of concrete mix depends on its paste volume, paste composition, and the type of aggregate used. Concrete testing was performed, and concrete properties including slump, compressive strength, and tensile splitting test were tested. The effect of aggregate shape on workability was evaluated by comparing one aggregate combination to another. It was found that the aggregate combination with S/A= 0.4 GR-B-CA+NA-A-FA had optimum workability properties and generally, GR-B-CA+NA-A-FA consistently had the highest workability, as well as the highest paste volume demand. This can be attributed to its poor grading as a result of the gaps in GR-B-CA content. Compared with NA-A-CA + NA-A-FA, it resulted in concrete mixtures with lower paste volume demand.

Highlights

Concrete is a mixture of cementitious material, aggregate, and water
To identify differences in the performance relating to material properties of concrete mixtures, two coarse aggregates were used, a well-rounded natural coarse aggregate represented as NA-A-CA and a cubical, angular granite crushed coarse aggregate represented as GR-B-CA and a well-rounded natural fine aggregate was tested
Sieve analysis of fine aggregate From the sieve analysis of natural fine aggregate (NA-A-FA) as shown in Fig. 1 below, the highest percent cumulative retained is in sieve No 200, while it passed 100% in No5, showing high level of uniformity in grain sizes

Summary

Introduction

Aggregate is the main constituent of concrete and commonly considered inert filler, which accounts for 60 to 80 percent of the volume and 70 to 85 percent of the weight of concrete [1,2,3]. Aggregate is considered inert filler, it is a necessary component that defines the concrete’s thermal and elastic properties and dimensional stability [2]. According to [4], aggregate is classified as two different types, coarse and fine. Texture, and grading influence workability, finishability, bleeding, pumpability, cost and segregation of fresh concrete and affect strength, stiffness, shrinkage, creep, density, permeability, durability and on overall performance of fresh concrete [5]

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