Abstract
This paper presents findings of an experimental study conducted to evaluate the performance of metakaolin (MK) for potential use as a supplementary cementitious material or cement extender in South Africa. In this study, various proportions consisting of 0%, 5%, 10%, 15% MK were incorporated into ordinary Portland cement CEM I 52.5 N, then used to prepare mortar mixtures. Various mechanical and durability properties were measured comprising flowability, compressive strength, pozzolanic activity with lime, drying shrinkage, alkali - silica reaction (ASR) and sulphate resistance. Analytical studies were done using X - ray diffraction and scanning electron microscopy. It was found that incorporation of 10%–15% MK into Portland cement led to improved flowability, compressive strength increase and lower drying shrinkage, while ASR and sulphate attack processes were effectively mitigated. Results showed that the MK extender satisfied ASTM C618 specified criteria for ‘Class N’ pozzolan. Incorporation of 15% MK into Portland cement also met the requirements categorising the blend as CEM II/A–P 42.5 N cement type of SANS EN 50197–1.
Original language | English |
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Article number | 100154 |
Journal | Developments in the Built Environment |
Volume | 14 |
DOIs | |
Publication status | Published - Apr 2023 |
Keywords
- Alkali
- Compressive strength
- Drying shrinkage
- Extender
- Metakaolin
- Pozzolan
- Silica reaction
- Sulphate attack
- Supplementary cementitious materials
ASJC Scopus subject areas
- Architecture
- Civil and Structural Engineering
- Building and Construction
- Materials Science (miscellaneous)
- Computer Science Applications
- Computer Graphics and Computer-Aided Design