Unlocking the potential of biopolymer soil stabilisation
Lead Research Organisation:
University of Sheffield
Department Name: Civil and Structural Engineering
Abstract
The global soil stabilisation market is forecast to grow to $35 billion by 2027 driven primarily by infrastructure and construction activities and exacerbated by the increasingly urgent need to adapt to climate change, flood risk and sea-level rise.
Cement and lime are widely used to stabilise soil, but suffer from significant carbon and energy costs. Naturally sourced biopolymers are a promising low carbon 'green' substitute, achieving higher strength in stabilised soils than cement and at similar cost. However, widespread uptake of biopolymers is impeded by the fact that they suffer from (a) poor water resistance and (b) poor resistance to biodegradation over time.
To address these limitations, this proposal aims to investigate novel biopolymer treatment processes which have been designed from the molecular level up and which can be applied at the soil/biopolymer mixing stage. These have the scope to provide water and biodegradation resistance using only small volumes of additional natural materials and if successfully demonstrated have the potential to achieve a transformational impact on the soil stabilisation market.
Cement and lime are widely used to stabilise soil, but suffer from significant carbon and energy costs. Naturally sourced biopolymers are a promising low carbon 'green' substitute, achieving higher strength in stabilised soils than cement and at similar cost. However, widespread uptake of biopolymers is impeded by the fact that they suffer from (a) poor water resistance and (b) poor resistance to biodegradation over time.
To address these limitations, this proposal aims to investigate novel biopolymer treatment processes which have been designed from the molecular level up and which can be applied at the soil/biopolymer mixing stage. These have the scope to provide water and biodegradation resistance using only small volumes of additional natural materials and if successfully demonstrated have the potential to achieve a transformational impact on the soil stabilisation market.
Organisations
Publications
| Description | Cement and lime are widely used to stabilise soil but suffer from significant carbon and energy costs. Naturally sourced biopolymers are a promising low carbon 'green' substitute, achieving higher strength in stabilised soils than cement and at similar cost. However, widespread uptake of biopolymers is impeded by the fact that they suffer from (a) poor water resistance and (b) poor resistance to biodegradation over time. In this proof of concept study we have demonstrated that acetylation (a process successfully used in 'green' timber treatment) can be used to enhance the water resistance of biopolymer treated soils while achieving similar strengths to cement and lime treatment. In contrast to cement stabilisation that might require a 1 part cement to 9 parts soil mix, biopolymer stabilisation typically requires 1 part biopolymer to 99 parts soil. We were able to demonstrate that the additional acetylation treatment typically requires only 0.25 parts treatment agent to 1 part of biopolymer, and can maintain significant strengths in treated soils after full immersion in water, in contrast to untreated specimens. A range of treatment protocols have been evaluated including those suitable for field application and those for use in factory environments and a conceptual model for the underlying physical/chemical processes was developed to aid in further design of treatment processes. |
| Exploitation Route | Soil stabilization is of interest to many organizations, including construction (geotechnical and structural), materials production (e.g. bricks and blocks) and low-cost self build applications (domestic and overseas). We are developing a follow up grant application to convert this proof of concept study to a process acceptable to industry early adopters, and liaising with a local industrial partner to explore novel use of the stabilized soil as a concrete substitute in specialist structural applications. Funding for this has been sought for a small pilot study. |
| Sectors | Construction |