Biochar-augmented carbon-negative concrete

Liang Chen, Yuying Zhang, Lei Wang, Shaoqin Ruan, Junfeng Chen, Huanyu Li, Jian Yang, Viktor Mechtcherine, Daniel C.W. Tsang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Biochar is a waste-derived carbon-based material that can sequester carbon. This study proposed a revolutionary design of carbon-negative concrete with a large volume of biochar incorporation and elaborated the roles of biochar in the cement hydration and microstructure development of biochar-augmented concrete. The total CO2 emissions and economic values of biochar-augmented concrete were, for the first time, quantified by conducting life cycle assessment and cost-benefit analysis. Biochar as aggregate in concrete promoted the cement hydration process, facilitating the formation of calcium-silicate-hydrate (C-S-H) gel and enhancing the polymerization degree of C-S-H gel via internal curing. The incorporation of supplementary cementitious materials (SCMs) in the binder further enhanced the mechanical strength of biochar-augmented concrete via time-dependent pozzolanic reaction. The life cycle assessment confirmed that the biochar incorporation significantly reduced CO2 emissions, and most importantly, the combined use of biochar and SCMs successfully achieved carbon-negative concrete production. Preliminary cost and benefit analysis illustrated that the biochar-augmented concrete could yield satisfactory overall economic profits. Considering the mechanical performance, resource availability, negative CO2 emissions, and economic profits, the 30BC-MK (with biochar as aggregate and metakaolin as a binder representing 30 wt% and 9 wt%, respectively) was the most promising mixture, which could sequester 59 kg CO2 tonne-1 and potentially generate the overall profit of 35.4 USD m−3. In summary, our novel design of biochar-augmented concrete can open up a new field of biochar application that produces technically feasible and financially profitable carbon-negative construction materials.

Original languageEnglish
Article number133946
JournalChemical Engineering Journal
Volume431
DOIs
Publication statusPublished - 1 Mar 2022

Keywords

  • Carbon neutrality
  • Circular economy
  • Eco-friendly construction materials
  • Engineered biochar
  • Life cycle assessment
  • Sustainable waste management

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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