Influence of pozzolanic addition on strength and microstructure of metakaolin-based concrete

PLoS One. 2024 Apr 10;19(4):e0298761. doi: 10.1371/journal.pone.0298761. eCollection 2024.

Abstract

The intent of this study is to explore the physical properties and long-term performance of concrete made with metakaolin (MK) as a binder, using microsilica (MS) and nanosilica (NS) as substitutes for a portion of the ordinary Portland cement (OPC) content. The dosage of MS was varied from 5% to 15% for OPC-MK-MS blends, and the dosage of NS was varied from 0.5% to 1.5% for OPC-MK-NS blends. Incorporation of these pozzolans accelerated the hardening process and reduced the flowability, consistency, and setting time of the cement paste. In addition, it produced a denser matrix, improving the strength of the concrete matrix, as confirmed by scanning electron microscopy and X-ray diffraction analysis. The use of MS enhanced the strength by 10.37%, and the utilization of NS increased the strength by 11.48% at 28 days. It also reduced the penetrability of the matrix with a maximum reduction in the water absorption (35.82%) and improved the resistance to the sulfate attack for specimens containing 1% NS in the presence of 10% MK. Based on these results, NS in the presence of MK can be used to obtain cementitious structures with the enhanced strength and durability.

MeSH terms

  • Bone Cements*
  • Crystallography, X-Ray
  • Glass Ionomer Cements*
  • Intention
  • Microscopy, Electron, Scanning

Substances

  • Bone Cements
  • Glass Ionomer Cements

Grants and funding

The authors are thankful to the Deanship of Scientific Research at King Khalid University, Abha, Saudi Arabia for providing support to this research work through Large Groups RGP2/563/44. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.