Denayer C.; Shtiza A.; Schlegel T.; Haas S. (2019) Geotechnical know-how that supports decision making towards sustainable infrastructure

ABSTRACT:

To manage the geotechnical challenge of a road construction in a sensible region in Northern France, multiple options were considered and compared to minimize and mitigate impacts towards a sustainable and integrated solution. For the construction of the by-pass motorway around the city of Reims (France) three techniques were assessed: 1. On-site soil stabilization with lime, 2. Natural drying and 3. Soil replacement (transport and back fill with suitable soil). To handle the wet clay soils from a road construction site a Life Cycle Cost Analysis and Social impacts were developed based on this well-documented real example instead of using a theoretical generic case. The soil stabilization using this technique resulted in overall sustainable benefits of finalizing the works quicker (option 1), minimize exposure of road contractors to risks (fatalities/injuries) and concluded that option 1 (soil stabilization) is the cheapest solution followed by natural drying (2) and by soil replacement (3). Over time also the carbonation for lime-based applications resulting from the uptake of carbon dioxide from the ambient air. The presence of water vapour is required to enable the reaction between the CO2 and the lime (calcium hydroxide). Through this carbonation reaction the hardening of air-lime is net uptaker of CO2 as illustrated using lime in road stabilization.