What is a Circular economy?
A circular economy is an industrial system that is restorative or regenerative by intention and design. A circular economy replaces the linear economy, and its ‘end-of-life’ concept with restoration and regeneration, shifts towards the use of renewable energy, eliminates the use of toxic chemicals and aims for the elimination of waste through the design of materials, products and systems that can be repaired and reused.
The circular economy concept shown in the bottom part of the Figures below illustrates an evolution of the current Linear Economy (top part) to the Circular Economy (bottom part) which is achieved through the application of principles: maintain, repair, reuse, remanufacture and recycle, as well as leasing and servicing.
definition by LETI
Trying to achieve the carbon targets cannot be realised without stretching the idea of incorporating a fully circular economy. To reach a zero-carbon national economy, the consideration of design and construction of infrastructure and buildings should be thought not in a separate manner however thought of as a circular cycle of things being reused and put back into the system as it is the core principles of a circular economy. Circular economy principles could be achieved only by redeveloping the entire value chain to generate an alternative approach to developments.
Circular Economy/net-zero
The core pillar for achieving a circular development of the construction sector will be to extremely emphasise the need for interdisciplinary collaboration of all the stakeholders associated with the pipeline of project delivery.
Contractors, designers, suppliers, facility managers and investors should all work from an early stage of the projects to deliver projects of a circular manner achieved by having a system-thinking approach with considerations of the social, financial, natural, built environment and human frameworks in which businesses operate. To achieve the full potential of a circular way of thinking a life cycle thinking should be established as a standard work of assessment. Assessments developed in the industry such as life cycle assessment (LCA), life cycle cost (LCC) should be consistent to succeed in a modern circular economy.
What is LCA?
The life cycle approach way of thinking is dating back to the 1960s where it was first introduced by Harry Teasley at Coca-Cola Company in 1969, where he used LCA for purposes of quantifying the energy, material and environmental burden from the packages of the product (DU, 2015). Sustainability is very difficult to measure and quantify, however, there is a solution that is based on life cycle thinking (LCT). Various standards introduced such as the BS EN ISO 14040-2016, BS EN 15804-2012 and BS EN 15978 outline the fundamental techniques and principles of LCA assessment and quantification methodology in general and specifically for the build environment industry.
Furthermore, the sustainability performance of an asset is not only related to environmental but also aspects of social and economic performance is assessed from a whole-life standpoint (BS15978, 2011). The use of LCA can assist to identify opportunities to improve the environmental performance of products at various stages of their life cycle, by enlightening decision-makers in the industry with real data, with the purpose to revaluate strategies and planning based on a holistic cycle approach to projects (ISO14040, 2006).
LCA measuring techniques provide results based on scientific data analysis that help to set a benchmark on the environmental burden of processes and assets and help to spot environmentally inefficient components of systems with the aim of re-think and redesign for improving environmental performance (ISO14040, 2006). When LCA is adopted from an early stage of a bridge project a quantitative comparison of the environmental performance of different design options could be achieved.
For this study, LCA methodology is applied in accordance with ISO standards and other recognised approaches with the aim of analysing the global warming potential by calculating the carbon dioxide equivalent emissions (tCO2e) of bridges for stages from Cradle to Practical completion (Modules A1-A5).