ABSTRACT
Today, the construction industry represents 6 to 8% of total GWP emission worldwide (Lee and Romero, 2023). Actions have been taken for several years to reduce these emissions, but progress is still being made to reach the global greenhouse gas emission reduction targets. MSE walls are mainly composed of a facing made of concrete or welded mesh panels with a backfill reinforced by metallic or geosynthetic elements. They are one of the least CO2 intensive earth retaining structures. This article deals with the proposal of technical solutions to reduce each component’s carbon footprint of a MSE wall (facing, reinforcement, backfill) and to estimate the CO2 emission reduction at the construction project level (calculations based on a specific and real construction project). Concerning the concrete panels, the replacement of ordinary Portland concrete by low carbon concrete is a key parameter in the reduction of CO2 emissions of the construction of a MSE wall (estimation of CO2 emission reduction between 15% and 30% on the total CO2 emission for this project). Regarding the backfill reinforcement, using geosynthetic reinforcement instead of steel reinforcement is also a way to reduce CO2 emissions. Indeed, steel reinforcement accounts for around 20% of total CO2 emissions for this project, while geosynthetic reinforcement accounts for around 5%. Finally, regarding backfill, its carbon impact represents about 45% of this project's overall CO2 emissions, considering the materials and their transportation. Thus, using recycled materials as backfill or marginal backfill to reduce transportation distance are essential.
