In order to predict consequences of replacing jet grouting with biogrouting, and identify major contributors to the cost of both technologies, a large road project in Stockholm, Sweden, was used as a case study. Jet grouting had been used to seal the contact between sheet piling and bedrock, biogrouting for the same function was computed. A comparative environmental and economical assessment was carried out using life cycle assessment (LCA). The results show that biogrouting was cheaper than jet grouting and would have had lower environmental impact. The major difference was the transport and use of heavier equipment for jet grouting. Biogrouting also used less water and produced less landfilled waste. However, the production of urea and CaCl(2) for biogrouting required much energy.

Life cycle assessment (LCA) is becoming an increasingly important environmental systems analysis tool in the construction sector for the identification of measures and strategies to reduce the environmental impact of buildings throughout the whole value chain. Geotechnical processes, such as earthworks, ground improvement and foundation construction, are often energy- and resource-intensive. Geotechnical works can thus play an important role in moving towards more sustainable building construction practices. This article reviews recent applications of LCA of buildings, including foundations as the focus or part of the system studied, based on the ISO 14040/44 standards. The system boundaries of geotechnical works are defined and a conceptual model for LCA of geotechnical works in building construction is proposed. The results of the literature review showed that the application of LCA to the building substructure is currently under development, but still in a fragmented state. There is a need for a unified framework for LCA of geotechnical works in building construction, especially regarding the definition of the functional unit, the choice of system boundaries, the appropriateness of inventory data, and the selection of impact categories. The conceptual model focuses on the demonstration of inventory flows and system boundaries and can serve as a basis for scope definition in future LCA studies of geotechnical works in building construction. It may also support effective communication between different actors and stakeholders regarding environmental sustainability in the construction sector.

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The construction and demolition of infrastructure can produce a surplus of excavated soils that ends up at landfills. This practice is not sustainable, and approaches are needed to reduce soil waste and minimize environmental and human health hazards. The “Reuse of urban soils and sites” Working Group in the European Large Geotechnical Institute Platform (ELGIP) works towards a safe and resource efficient use of excavated soils for construction. By considering relevant literature and practicals based on experience in the participating ELGIP countries (France, Norway, Portugal, Slovenia and Sweden), this study presents current practice related to the reuse of excavated soils, and the main barriers (regulatory, organizational, logistical and material quality) to effectively reuse them. Results show that there is no consensus on the best strategies to manage excavated soils in urban areas. This paper provides suggestions of ways in which stakeholders can increase reuse of excavated soils.

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