Soil material circular economy in infrastructure construction - capturing untapped economic potential

Abstract

Climate change and national emission reduction targets have driven construction companies to cut greenhouse gas emissions from their operations. To reach emission reduction targets, construction companies have recognized that cutting emissions requires improved operations, waste reduction and new circular economy solutions. In addition to emission reduction targets, the implementation of the principles of the circular economy into earthwork construction enables a construction company to gain significant competitive advantage. At present, in this re-search client construction company, soil recycling is part of the operational management of a project, but to maximize recycling, soil recycling planning must become an integral part of project implementation, from planning to execution.

This thesis investigated the current state of soil material recycling from the perspective of an infrastructure construction company. Also, the study examines the untapped economic potential in enhancing soil material circular economy. The aim of the study was to form an understanding of how soil recycling should be organized in order to capture the untapped economic potential. The results of the research are based on a multi-case study involving nine projects from infrastructure company and a workshop involving construction professionals from the company. The research material was collected through semi-structured interviews.

According to this study, the circular economy of soils has long been carried out in infra-structure construction companies. Today, soil recycling takes place on a project-by-project basis and the responsibility for the planning and implementation of recycling lies with the operational management of the project. There is no systematic exchange of information and planning of recycling soil between projects. At present, not all surplus soil can be recycled, but a part of the soil materials had to be disposed of in a landfill. The biggest challenges for soil recycling in a construction company are the lack of information and areas for soil reuse and storage. A major weakness of the current soil recycling operating model is that planning is part of the operational management of the project. The study made it clear that soil recycling planning should be integrated into project planning and the process should be made more systematic. Some of the projects involved in the study had successfully recycled the soil material, resulting in about two percentage cost savings of the project's budgeted costs. Based on this research, large-scale systematic recycling of soil material has significant potential to improve the economic performance of construction company.

The main result of the study is a framework, which provides a guide on how the planning and implementation of soil recycling is taken as a systematic process to a part of the project. The framework was used to address the challenges of soil recycling identified in the study. Another key finding of the study is that people working in earthwork construction have a high level of motivation and interest to soil recycling, but there is a lack of practice in how recycling is implemented. The study highlighted that, the key requirement for large-scale soil recycling is the resourcing of a soil coordinator, who would be responsible for supporting projects in the planning and implementation of soil recycling. Another requirement raised in the study was the need to develop an information system for soil management.