Multiscale analysis of the environmental impacts of the concrete masonry: from masonry unit to building

Abstract

Life Cycle Analysis of buildings can be led at various scales: from construction products one by drawing the Environmental Product Declarations according to EN 15804+A1 to building’s one by assessing the environmental performance of the buildings according to EN 15978. The new French Labelling scheme “Energie Positive & Reduction Carbone” has adopted a multi-criteria and multi-stage approach to declare the energy consumptions and environmental efficiency of new buildings. A special focus has been put on Greenhouse gas emissions by defining a set of global threshold and subthreshold values covering the whole life cycle of the building and only the contribution Product and Construction Process stage including equipment. Results of different French cases studies for collective housing buildings and single houses shows a variation of less than 10% of the global emissions of greenhouse gas for buildings of different mode of construction (concrete structure, concrete masonry, clay masonry, wood structure …) having a similar energy efficiency of their thermal envelope. The contribution of concrete masonry units typically ranges from 2.5 to 10% of the total amount of the CO2 emission for the Product and Construction Process stages and consequently less than 5% of the emission for the total life cycle, respectively 4–15% and less than 8% for collective housing buildings. No significative differences of the environmental impact calculated as greenhouse gas emissions at the building’s scale can be observed although the environmental impacts of the different type of concrete masonry units (dense and lightweight aggregates, composite blocks including mineral foam) vary significantly.