Environmental performance of miscanthus-lime lightweight concrete using life cycle assessment: Application in external wall assemblies

Fabrice Ntimugura, Raffaele Vinai, Anna B. Harper, Pete Walker

Research output: Contribution to journalArticlepeer-review

Abstract

In the UK context, miscanthus is a potential alternative perennial crop for the development of bio-based building materials. This paper presents the environmental benefits of using miscanthus shives in lightweight blocks and their potential application in wall assemblies. A systemic life cycle assessment (LCA) is carried out for miscanthus-lime blocks, and the effects of binder type and binder content are discussed. The environmental performance-based analysis reveals that miscanthus blocks can capture 135 kg CO2eq/m3 for an assumed 100-years life period. The impact analysis using the University of Leiden, institute of environmental science (CML) baseline (v4.4) method shows that 75% of the greenhouse gas emissions are attributable to the production of mineral binders. A reduction of binder to aggregate ratio from 2.0 to 1.5 reduces greenhouse gas emissions by 32.9%. The use of 10 wt% mineral additions can potentially stabilise blocks while having little effect on their overall environmental impacts. The environmental profiles of wall systems incorporating miscanthus-lime blocks have been evaluated in this this study. Combining miscanthus blocks with fired clay bricks enables a potential low carbon retrofitting technique for the current stock of residential buildings in the UK. Timber-framed system filled with miscanthus blocks enables a carbon storage of ~97.3 kg CO2eq/m2, which presents a potential carbon offsetting strategy in new-build dwellings. Consideration should be given to the potential negative impacts related to agricultural activities for the production of miscanthus shives. The largest negative environmental impact was ozone layer depletion, where a relative difference of 12.8% was recorded between miscanthus timber-framed wall and a typical solid wall insulated with mineral wool. It appears that miscanthus-lime composites can substantially improve the environmental profile of wall assemblies and sustainability be applied in existing uninsulated masonry walls or incorporated in timber- framed new-build houses.

Original languageEnglish
Article numbere00253
JournalSustainable Materials and Technologies
Volume28
Early online date29 Jan 2021
DOIs
Publication statusE-pub ahead of print - 29 Jan 2021

Keywords

  • Bio-based building materials
  • Carbon capture
  • Environmental impact
  • Miscanthus
  • Thermal insulation

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)
  • Waste Management and Disposal
  • Industrial and Manufacturing Engineering

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