Development of Heavyweight Self-Compacting Concrete and Ambient-Cured Heavyweight Geopolymer Concrete Using Magnetite Aggregates.

Afsaneh Valizadeh,Farhad Aslani,Zohaib Asif,Matt Roso

doi:10.3390/ma12071035

Afsaneh Valizadeh, Farhad Aslani + Show 2 more

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https://doi.org/10.3390/ma12071035

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Journal: Materials	Publication Date: Mar 28, 2019
Citations: 25	License type: CC BY 4.0

Affiliation: University of Western Australia, Edith Cowan University

Abstract

Heavyweight self-compacting concrete (HWSCC) and heavyweight geopolymer concrete (HWGC) are new types of concrete that integrate the advantages of heavyweight concrete (HWC) with self-compacting concrete (SCC) and geopolymer concrete (GC), respectively. The replacement of natural coarse aggregates with magnetite aggregates in control SCC and control GC at volume ratios of 50%, 75%, and 100% was considered in this study to obtain heavyweight concrete classifications, according to British standards, which provide proper protection from sources that emit harmful radiations in medical and nuclear industries and may also be used in many offshore structures. The main aim of this study is to examine the fresh and mechanical properties of both types of mixes. The experimental program investigates the fresh properties of HWSCC and HWGC through the slump flow test. However, J-ring tests were only conducted for HWSCC mixes to ensure the flow requirements in order to achieve self-compacting properties. Moreover, the mechanical properties of both type of mixes were investigated after 7 and 28 days curing at an ambient temperature. The standard 100 × 200 mm cylinders were subjected to compressive and tensile tests. Furthermore, the flexural strength were examined by testing 450 × 100 × 100 mm prisms under four-point loading. The flexural load-displacement relationship for all mixes were also investigated. The results indicated that the maximum compressive strength of 53.54 MPa was achieved by using the control SCC mix after 28 days. However, in HWGC mixes, the maximum compressive strength of 31.31 MPa was achieved by 25% magnetite replacement samples. The overall result shows the strength of HWSCC decreases by increasing magnetite aggregate proportions, while, in HWGC mixes, the compressive strength increased with 50% magnetite replacement followed by a decrease in strength by 75% and 100% magnetite replacements. The maximum densities of 2901 and 2896 kg/m3 were obtained by 100% magnetite replacements in HWSCC and HWGC, respectively.

Highlights

With the advancement in technology and global demand for energy, focus has shifted from traditional energies derived from fossil fuels to non-carbon emitting power generation such as nuclear energy
The results indicated that the maximum compressive strength of 53.54 MPa was achieved by using the control self-consolidating concrete (SCC) mix after 28 days
The lowest compressive strength was achieved by HWSCC2 with 75% aggregate replacement after 28 days of ambient temperature curing. Since these results indicate a drop in compressive strength from CM1 containing regular aggregate to the Heavyweight self-compacting concrete (HWSCC) mixes containing magnetite aggregate, it is possible that the significant difference of densities and improper interlocking of the regular and magnetite aggregates lead to a reduction of compressive strength

Summary

Introduction

With the advancement in technology and global demand for energy, focus has shifted from traditional energies derived from fossil fuels to non-carbon emitting power generation such as nuclear energy. The harmful radiation-emitting devices, which threaten human life, had been extensively used with the latest development all over the globe. Heavyweight concrete is broadly utilized material for reactor protecting because of its less expensive and attractive mechanical. The heavyweight aggregates in concrete plays an imperative role in enhancing solid protecting properties and has been demonstrated to have great shielding properties for lessening photons and neutrons [3,4]. Self-compacting concrete, which is known as self-consolidating concrete (SCC) is the latest concrete technology that has been used in many high-rise concrete projects all over the globe. SCC is known for its excellent deformability, high resistance to segregation, and successful use in congested reinforced concrete structures characterized by difficult casting conditions that do not allow for vibration [5]

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