NECESSARY’ – Net zEro CEments for Soil Stabilisation via wAste RecoverY

   Faculty of Computing, Engineering and the Built Environment

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  Dr Paul Sargent, Dr Angela Rolfe, Dr Adrian Boyd  No more applications being accepted  Competition Funded PhD Project (Students Worldwide)

About the Project

Significant sections of civil engineering infrastructure networks (e.g. roads, railways) cross large areas of soft ground (e.g. river floodplains). To permit construction in such troublesome areas, ‘heavy engineering’ solutions such as reinforced-concrete piling are commonly used. However, continuing this approach is unfavourable due to: 1) the high costs of Portland cement and steel in concrete and 2) Portland cement manufacture generates 8-10% of global CO2 emissions.

Deep soil mixing (DSM) is an increasingly popular alternative ground improvement technique to concrete piling that: 1) produces zero waste; 2) achieves engineering strengths comparable with concrete and 3) makes time savings. DSM involves mixing cement into the ground, which produces a ‘soil-concrete’ to form foundations.

To date, DSM has used Portland cement due to its ability to achieve long term high strengths. However, continuing this approach is unsustainable if the civil engineering industry is to achieve net zero carbon emissions by 2050 and limit global warming to 1.5oC. It is therefore NECESSARY to develop and commercialise new Portland cement-free binders.

The ‘NECESSARY’ project aims to develop a new generation of Portland cement-free Net zEro carbon CEments for deep mixing Soil Stabilisation via wAste RecoverY. This more sustainable approach intends to facilitate growth within the UK’s circular economy and will help develop a new ‘state-of-the-art’ practice in low carbon DSM ground improvement technology. The project will involve a combination of laboratory work (e.g. soil mechanics testing, mineralogy, microstructure visualisation) to assess the engineering performance of new low carbon cements developed, along with an environmental assessment.

Architecture, Building & Planning (3) Engineering (12) Environmental Sciences (13)


Sargent, P. and Rouainia, M., 2023. A new framework for quantifying the structure of undisturbed and artificially cemented alluvium. Géotechnique, 73 (2), 143-164. https://doi.or ar g/10.1680/jgeot.21.00059.
​Sargent, P., Gonzalez, J. and Ennis, C. J., 2023. Compressibility, structure, and leaching assessments of an alluvium stabilized with a biochar-slag binder. Journal of Geotechnical and Geoenvironmental Engineering, 149 (12), 04023114.
​Núñez, V., Lotero, A., Bastos, C. A., Sargent, P. and Consoli, N. C., 2023. Mechanical and microstructure analysis of mass-stabilized organic clay thermally cured using a ternary binder. Acta Geotechnica.
​Gonzalez, J., Sargent P. and Ennis, C., 2021. Sewage treatment sludge biochar activated blast furnace slag as a low carbon binder for soft soil stabilisation. Journal of Cleaner Production. 311, 127553.
​Sargent, P., Jaber, N. H. and Rouainia, M., 2020. Mineralogy and microstructure effects on the stiffness of activated slag treated alluvium. Géotechnique Letters. 10 (2), 327-335.
​Sargent, P., Rouainia, M., Diambra, A., Nash, D., and Hughes, P. N., 2020. Small to large strain mechanical behaviour of an alluvium stabilised with low carbon secondary minerals. Construction and Building Materials. 232, 117174.
​Sargent, P., Hughes, P. N. and Rouainia, M., 2016. A new low carbon cementitious binder for stabilising weak ground conditions through deep soil mixing. Soils and Foundations. 56 (6), 1021-1034.
​Sargent, P., Hughes, P. N., Rouainia, M. and White, M., 2013. The use of alkali activated waste binders in enhancing the mechanical properties and durability of soft alluvial soils. Engineering Geology 152 (1), 96-108.​
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 About the Project