Journal of CO2 Utilization (Jun 2024)

Novel utilization of waste concrete powder in alkali-activated binder

  • Aidarus Yonis,
  • Prabhat Vashistha,
  • Yanchen Oinam,
  • Martin Cyr,
  • Sukhoon Pyo

Journal volume & issue
Vol. 84
p. 102859

Abstract

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This experimental study investigates a novel approach to utilize waste concrete powder (WCP) in conjunction with metakaolin as a precursor in the production of alkali-activated binder for sustainable consumption of construction and demolition waste. A Chapelle test confirms the presence of reactive silica in thermo-mechanically activated WCP. Different alkali-activated mixtures with metakaolin replacement ranging from 0 % to 80 % were prepared. The mixture with 40 % activated WCP, with a sodium silicate to sodium hydroxide ratio of 2, achieved better compressive strength than the reference sample without WCP. Mineralogical analysis of the mixture pastes revealed that activated WCP-based mixtures developed geopolymer gel and C-S-H gel, contributing to better strength properties in the case of the mixture with 40 % activated WCP. Life cycle analysis demonstrated that incorporating 40 % thermo-mechanically activated WCP by replacing metakaolin reduces carbon dioxide emissions by 49.5 % and 2.2 % compared to Portland cement and metakaolin-based binder, respectively.

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