Understanding Cement-Superplasticiser Interactions in Geopolymer Encapsulants for Safe Disposal of Radioactive Waste

Find Similar History 32 Claim Ownership Request Data Change Add Favourite

Title
Understanding Cement-Superplasticiser Interactions in Geopolymer Encapsulants for Safe Disposal of Radioactive Waste

CoPED ID
96aae055-92ba-470c-ad30-6442a948c608

Status
Active

Funder

Value
No funds listed.

Start Date
Sept. 25, 2022

End Date
Sept. 24, 2026

Description

More Like This


In the UK, over 150,000m3 of radioactive waste (enough to fill 60 Olympic size swimming pools) has been produced to date. Most of this radioactive waste needs conditioning by encapsulating it in cement to prevent release to the biosphere.

Geopolymer cements are ideally suited for this, providing low viscosity, increased tolerance to problematic wastes, and lower leach rates of fission products than other encapsulants. Geopolymer cements also have significantly lower CO2 emissions associated with their production compared to traditional Portland cement, reducing these by as much as 90%, and are critical in helping to reach Net Zero 2050.

Superplasticising dispersants can further improve flow characteristics at a given water content, and reduce the requirement for tight specifications on cement powders needed at encapsulation plants. However, superplasticiser behaviour in geopolymers differs significantly from that in common Portland cement encapsulants, due to extensive differences between aqueous and solid-state chemistry in each case. There is little information on what parameters are critical to reliable application.

Chemical differences between geopolymers and Portland cement encapsulants lead to different superplasticiser effects (exacerbated by variability in powder physical/chemical characteristics), and little is known about which superplasticisers are most suitable for geopolymers. It is essential that we understand the fundamental cement-superplasticiser interactions, and effect on geopolymer encapsulant performance, so that robust specifications can be developed, and encapsulant properties and performance can be predicted.

This PhD examines interactions between organic superplasticisers and inorganic cement particles in geopolymer encapsulants, benchmarked against common Portland cement-based encapsulants. It adopts a new in-situ characterisation approach (including surface-specific techniques, spectroscopic and microstructural characterisation) to investigate mechanisms and kinetics of organic-inorganic interactions, and effects on performance.

We will elucidate the fundamental processes controlling dispersion, fluidisation and reaction of these cements, and design, produce and test novel encapsulant formulations with enhanced performance.

University of Sheffield LEAD_ORG
Sellafield Ltd STUDENT_PP_ORG

Brant Walkley SUPER_PER
Cameron Halliwell STUDENT_PER

Subjects by relevance
  1. Cement
  2. Radioactive waste
  3. Geopolymers
  4. Emissions
  5. Wastes
  6. Nuclear waste
  7. Cement industry

Extracted key phrases
  1. Common Portland cement encapsulant
  2. Geopolymer cement
  3. Geopolymer encapsulant performance
  4. Traditional Portland cement
  5. Inorganic cement particle
  6. Fundamental cement
  7. Cement powder
  8. Superplasticiser interaction
  9. Inorganic interaction
  10. Different superplasticiser effect
  11. Novel encapsulant formulation
  12. Geopolymer Encapsulants
  13. Safe Disposal
  14. Encapsulant property
  15. Organic superplasticiser

Related Pages

UKRI project entry

UK Project Locations