Mechanical Characteristics of Hardened Concrete with Different Mineral Admixtures: A Review

Tehmina Ayub,Fareed Ahmed Memon,Sadaqat Ullah Khan

doi:10.1155/2014/875082

Abstract

The available literature identifies that the addition of mineral admixture as partial replacement of cement improves the microstructure of the concrete (i.e., porosity and pore size distribution) as well as increasing the mechanical characteristics such as drying shrinkage and creep, compressive strength, tensile strength, flexural strength, and modulus of elasticity; however, no single document is available in which review and comparison of the influence of the addition of these mineral admixtures on the mechanical characteristics of the hardened pozzolanic concretes are presented. In this paper, based on the reported results in the literature, mechanical characteristics of hardened concrete partially containing mineral admixtures including fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA) are discussed and it is concluded that the content and particle size of mineral admixture are the parameters which significantly influence the mechanical properties of concrete. All mineral admixtures enhance the mechanical properties of concrete except FA and GGBS which do not show a significant effect on the strength of concrete at 28 days; however, gain in strength at later ages is considerable. Moreover, the comparison of the mechanical characteristics of different pozzolanic concretes suggests that RHA and SF are competitive.

Highlights

Many researchers addressed the deficiencies of concrete and some of them made significant efforts to improve the performance of concrete, especially permeability and durability of concrete as these are the immense concerns of the researchers
Researchers compared the properties of few mineral admixtures; for example, Mehta and Gjørv [8] compared the properties of Portland cement concrete containing condensed silica fume (SF) and fly ash (FA), Jianyong and Yan [9] and Bagel [10] compared SF and ground granulated blast furnace slag (GGBS), Justice et al [11] and Poon et al [12]
Almusallam [25] determined the effect of w/b ratio on the initial and secant modulus of ordinary Portland cement (OPC) and FA concrete and it can be seen from the results shown in the Table 3 that the modulus of elasticity increases with the increasing age and the difference in the initial and secant elastic modulus for the OPC is higher than FA concrete at w/c of 0.48 and 0.5

Summary

Introduction

Many researchers addressed the deficiencies of concrete and some of them made significant efforts to improve the performance of concrete, especially permeability and durability of concrete as these are the immense concerns of the researchers. The existing literature related to pozzolanic concretes shows that the use of mineral admixtures reduces the porosity of concrete if cement content is partially replaced by mineral admixture; the demand of blended cement has increased globally to produce denser to impermeable concretes [1], along with improving the strength of concrete such as compressive, tensile, and flexure ones. On one side, these mineral admixtures enable concrete to exhibit greater resistance against harmful solutions (e.g., acid and chemicals, etc.), freezing and thawing, chloride ion penetration, sulphate attack and carbonation, and so forth and, on the other side, they are important contributors for sustainable environment as partial replacement of cement and often called as “less energy intensive cementitious materials” [2]. Researchers compared the properties of few mineral admixtures; for example, Mehta and Gjørv [8] compared the properties of Portland cement concrete containing condensed silica fume (SF) and fly ash (FA), Jianyong and Yan [9] and Bagel [10] compared SF and ground granulated blast furnace slag (GGBS), Justice et al [11] and Poon et al [12]

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