When moving towards a circular economy, the impacts of replacing virgin materials with secondary materials need to be well examined. Also decision-makers put ever-higher emphasis on environmental impacts, GPP (Green Public... [ view full abstract ]
When moving towards a circular economy, the impacts of replacing virgin materials with secondary materials need to be well examined. Also decision-makers put ever-higher emphasis on environmental impacts, GPP (Green Public Procurement) promotes sustainable choices and environmental impacts as a criterion in public tendering. Besides the use of secondary raw materials promoting a circular urban economy, transport distances can be actively reduced, generating significant reductions in the environmental impacts of infra construction.
MELI is a tool for life cycle emission assessments of infra construction, targeting to promote material recycling and waste utilization. All the work stages from material production to transport and construction are covered in the analyses. Almost two decades of VTT’s IPR has been invested in MELI. Since MELI was first developed, the infra construction sector in Finland has agreed on product and method quality assurance through the Infra RYL code of building practice, and MELI has also been updated to fit into the Infra RYL nomenclature. In 2016, also a web based MELI tool was developed to improve the user interface to further promote user-friendliness. MELI enables infrastructure planners to estimate environmental impacts and to compare different material options already at early planning stage.
A case study comparing the environmental impacts between planned and executed solution of the construction of a road segment in Helsinki enlightens the importance of active decision-making and the potential for reduced environmental impacts in infra construction. The study was conducted at VTT using VTT’s in-house excel based tool for life cycle emission analysis, MELI (Maarakentamisen elinkaariarviointi). The main findings of the study were reduced environmental impacts due to initiatives to reduce transport distances, and the potential for further reduction due to alternative method and material choices.
One aim of the comparison study was to enlighten the difference in environmental impacts when replacing virgin materials with secondary materials. Virgin gravel was replaced with concrete waste for some embankments and part of the cement was replaced with ashes in soil stabilization. The study shows that the use of secondary raw materials significantly reduces the environmental impacts for some methods and materials, while the replacement of other materials had marginal environmental benefits.
When moving towards smarter city planning, a need for infrastructure planners to estimate environmental impacts and to compare different project solutions and material options already at planning stage arises. The preliminary data should be ready available as part of the decision-making process. MELI offers simplicity and user-friendliness, a simple tool for internal communication between infra planners and decision-makers.
