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

This is the final version. Available from Elsevier via the DOI in this record. 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 CO eq/m 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 CO eq/m , 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.Engineering and Physical Sciences Research Council (EPSRC)Natural Environment Research Council (NERC)NERC GW4+ Doctoral Training Partnership studentshi

Soil-steel composite bridge: An alternative design solution for short spans considering LCA

In a bridge project, several alternative design solutions can be functionally equivalent for the designated location. Today’s bridge constructions highly rely on the non-renewable resources, the consumption of fossil fuels, and the intensive usage of concrete. This urges designers to explore the new design options to mitigate the associated environmental burdens. When comparing to the concrete slab frame bridges (CFB), the soil-steel flexible culverts (or soil-steel composite bridge, SSCB) show advantages in ease erection, low maintenance as well as the competitive cost. However, its environmental performance has never been studied. This paper intends to compare the environmental performance of these two bridge types through the whole life cycle, based on 8 selected cases in Sweden. Unlike previous studies only limited to few impact indicators, this study comprehensively covers a wide range of indicators: including eleven types of mid-point impact categories, the cumulative energy demand (CED) and the associated cost. The construction phase, which seldom included previously, is a specific focus in this paper. The results find that: 1) the SSCBs show advantages over the CFBs in most of the investigated indicators; 2) the construction phase, when explicitly evaluated, may take up to 34% of the total life cycle environmental burdens; 3) the environmental performance of a bridge is closely linked with the bridge type selection, multiple indicators in the environmental domain, designers' preference, the construction phase, as well as the time schedule constraints

Life cycle sustainability assessment: An ongoing journey

As the call for sustainable solutions at operational, industrial, and policy level increases, the need for a comprehensive assessment tool has been addressed by literature and practitioners. In particular, for the definition of a complete framework, the application of a life cycle thinking lens is required to explore the longitudinal dimension of the impacts and possible indirect effects triggered on environmental, social, and economic levels. The definition of an integrated life cycle sustainability assessment framework is currently an ongoing journey, which is summarized in the present chapters. The narrative follows a set of milestones, namely the definition of the concept and the preliminary scheme in the early years, the pathway towards the implementation of a standardized set of tools, an anthology of significant case studies in different sectors, and an overview of the challenges identified by literature and yet remaining open for future researches