Success at the 45th Cement and Concrete Science Conference

The 45th Cement and Concrete Science Conference, a two-day meeting, is an annual opportunity for scientists and engineers from both industry and academia to come together to discuss the latest developments in the field of cement and concrete science. The meeting's residential setting and its tradition as a forum for the presentation of the very latest research encouraging informal and stimulating discussion. This year the event was held at the Convention Centre, Dublin, 

Geo and Sylvia are both part of the SMASH (Sustainable Materials at Sheffield) research group which is led by Professor Brant Walkley, Professor of Sustainable Engineering in the School of Chemical, Materials and Biological Engineering.   

Geo’s research focuses on the implementation of machine learning to optimise limestone calcined clay cement formulations for nuclear waste encapsulation. 

Speaking about the award Geo said: “I am honoured and grateful to have won this award. I am very thankful to my supervisors Prof. Brant Walkley and Prof. Solomon Brown who have supported me through this process. 

"My favourite part about the conference was the great discussions with other researchers and learning about the novel work being done in the sector.” 

Sylvia added “My research focuses on developing a solidification route for the safe disposal of radioiodine. I am very honoured to have received this award, it’s recognition of the work and the people behind it.

"The conference was a fantastic opportunity to learn about the developments in the industry and to network with fellow researchers.” 

Project abstracts

Machine learning optimisation of limestone calcined clay cements for nuclear waste encapsulation. Geovanni Vazquez

Aim and scope: Given that the diminishing supply of conventionally used supplementary cementitious materials (SCMs) is insufficient to meet future demand, the cement industry has begun to adopt more abundant SCMs to decarbonise cement and concrete. This led to the development of limestone calcined clay cement (LC 3 ), a ternary blend that utilises the synergy among limestone, calcined clay, and clinker [1]. The open literature on LC 3 focuses on construction applications, with limited studies on its use as a matrix for nuclear waste conditioning. However, LC 3 is expected to be widely deployed in the next decade, hence dictating the materials available for producing cements for nuclear waste management. Therefore, understanding how LC 3 systems perform across a broad formulation envelope will enable the industry to apply tailored blends and safely adopt LC 3 as a next-generation encapsulant. 

This study aims to develop a Gaussian process regression (GPR) model to accurately predict heat generation across a wide range of formulations. In addition, this model will provide statistical insights to analyse the drivers influencing the heat generated by the system. This approach will ultimately lead to the optimisation of LC 3 blends for nuclear waste conditioning whilst decreasing experimental time and cost.

The effect of iodine and phosphorus-to-aluminium molar ratio on the durability of phosphoric acid-based geopolymers. Sylvia Pestana

Aim and scope: 129 I is a long-lived radionuclide produced by reprocessing spent  nuclear fuel. Radioiodine can be easily mobilised in the environment and is harmful to human life, causing thyroid cancer. Cementation is a nuclear waste conditioning route that requires low temperatures, offers high throughput, simplicity and scalability. For these reasons, various cementitious materials have been studied for the safe disposal of 129 I. Portland cement (PC) and alkali-based geopolymers (AGP) were unsuccessful for radioiodine encapsulation, as the reducing environment reduced AgI, releasing iodine in PC, and the elevated pH led to the degradation of the adsorbent, resulting in the release of iodine in AGP. Phosphoric acid-based geopolymers are novel cementitious binders possessing optimal physicochemical properties and an acidic environment, which is particularly relevant for the encapsulation of 129 I. As a novel material, there is limited literature available on its durability and application for long-term disposal of radioiodine.

This study aims to investigate the effect of the P/Al molar ratio on water resistance, which is crucial for a geological disposal facility. Furthermore, the geopolymerisation reaction kinetics, chemical bonding, thermal stability and phase assemblage will be assessed to understand the effects of iodine inclusion and varying P/Al ratios in the matrix. Ultimately, the objective of this analysis is to optimise PGPs and evaluate their suitability for implementation as a solidification route for radioiodine disposal.