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Open AccessArticle

An Investigation of the Mechanical and Physical Characteristics of Cement Paste Incorporating Different Air Entraining Agents using X-ray Micro-Computed Tomography

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Building Materials and Construction Chemistry, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
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Structural Engineering Department, Mansoura University, Elgomhouria St., Mansoura City 35516, Egypt
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Department of Civil and Environmental Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 05006, Korea
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Faculty of Civil Engineering and Architecture, West Pomeranian University of Technology, Szczecin, Al. Piastow 50, 70-311 Szczecin, Poland
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School of Natural and Built Environments, University of South Australia, Mawson Lakes Blvd, Mawson Lakes SA 5095, Australia
*
Author to whom correspondence should be addressed.
Crystals 2020, 10(1), 23; https://doi.org/10.3390/cryst10010023
Received: 13 December 2019 / Revised: 2 January 2020 / Accepted: 4 January 2020 / Published: 6 January 2020
Improving the thermal insulation properties of cement-based materials is the key to reducing energy loss and consumption in buildings. Lightweight cement-based composites can be used efficiently for this purpose, as a structural material with load bearing ability or as a non-structural one for thermal insulation. In this research, lightweight cement pastes containing fly ash and cement were prepared and tested. In these mixes, three different techniques for producing air voids inside the cement paste were used through the incorporation of aluminum powder (AL), air entraining agent (AA), and hollow microspheres (AS). Several experiments were carried out in order to examine the structural and physical characteristics of the cement composites, including dry density, compressive strength, porosity and absorption. A Hot Disk device was used to evaluate the thermal conductivity of different cement composites. In addition, X-ray micro-computed tomography (micro-CT) was adopted to investigate the microstructure of the air-entrained cement pastes and the spatial distribution of the voids inside pastes without destroying the specimens. The experimental results obtained showed that AS specimens with admixture of hollow microspheres can improve the compressive strength of cement composites compared to other air entraining admixtures at the same density level. It was also confirmed that the incorporation of aluminum powder creates large voids, which have a negative effect on specimens’ strength and absorption. View Full-Text
Keywords: lightweight cement paste; air entraining agents; hollow microspheres; aluminum powder; pores; micro-CT; thermal insulation; compressive strength lightweight cement paste; air entraining agents; hollow microspheres; aluminum powder; pores; micro-CT; thermal insulation; compressive strength
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Abd Elrahman, M.; El Madawy, M.E.; Chung, S.-Y.; Majer, S.; Youssf, O.; Sikora, P. An Investigation of the Mechanical and Physical Characteristics of Cement Paste Incorporating Different Air Entraining Agents using X-ray Micro-Computed Tomography. Crystals 2020, 10, 23.

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