Natural bentonite as an internal curing agent in the production of eco-friendly ultra-high performance concrete with low autogenous shrinkage

Xudong Zhao, Jian Xin Lu, Weichen Tian, Shixiang Li, Xibo Qi, Zhonghe Shui, Chi Sun Poon

Research output: Journal article publicationJournal articleAcademic researchpeer-review

13 Citations (Scopus)

Abstract

This study investigated the use of natural bentonite as a green internal curing agent to prepare eco-friendly ultra-high performance concrete (UHPC) with low autogenous shrinkage and excellent heavy metal ions solidification properties. A method based on the pore fractal dimension analysis was used for assessing the performance of UHPC. Results showed the use of bentonite as a replacement of cement could effectively reduce the autogenous shrinkage through its internal curing effect without compromising the compressive strength and workability of UHPC. The UHPC containing 4% bentonite showed the best volume stability and durability, with a 26.9% reduction in the autogenous shrinking compared to the control UHPC. The addition of bentonite further improved ion penetration resistance and solidification of heavy metal ion owing to its ion exchange capacity. However, the enhancement effect decreased when the bentonite content was too high due to the volume change of bentonite. Two kinds of pore classification dimensions, Dmin and Dmax, were obtained from NMR results to build good correlations with the autogenous shrinkage and durability, respectively. Finally, the ecological evaluation demonstrated that the designed UHPC with bentonite had relatively low environmental impact compared to other internal curing material, which was promising to generate a cleaner product in the near future.

Original languageEnglish
Article number139471
JournalJournal of Cleaner Production
Volume428
DOIs
Publication statusPublished - 20 Nov 2023

Keywords

  • Autogenous shrinkage
  • Bentonite
  • Environmental impact
  • Heavy metal ions solidification
  • Pore fractal dimension
  • UHPC

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • General Environmental Science
  • Strategy and Management
  • Industrial and Manufacturing Engineering

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