Emission reduction through preconstruction and utilization of alternative materials in infrastructure projects

Construction have a significant impact on the amount of emitted green-house gas (GHG) and a potential to cut emissions is quite substantial. In this article, possibilities provided by preconstruction activities and utilization of alternative materials are discussed. Preconstruction means actions to be taken in advance when soils in the construction area are too soft. These actions may be e.g. deep mixing, replacement or preloading. Considering that constructed subgrades, ground improvement and some other earth works required for the infrastructure project can be very energy-intensive, emissions can be reduced substantially only if preconstruction options, areal mass balance and potentiality of alternative materials are identified early enough. Examined case studies also focus on possibilities to reduce emissions related to certain materials e.g. deep mixing binding agents. In deep mixing, blend of cement and quick lime is the most traditional binder component. Therefore, reducing the amount of cement + lime and selecting the cement type have a great impact on CO2 emissions. Cement amount can be reduced by alternative materials such as fly ash, blast furnace slag or gypsum. Possibilities to reduce CO2 emissions were studied in various infrastructure projects and reflected to climate strategies. The studies were focused on areas and operations where changes were possible such as transportation, construction materials or subgrade construction methods. This article describes the case studies related to construction of various infrastructure projects and identified possibilities to reduce emissions.