Cements of the Future and Future Nuclear Cements

There has been dramatic change in the operation of UK heavy industry over the past few decades, putting the availability of materials crucial to currently established Portland cement compositions for the application of radioactive waste encapsulation under question. The uncertainty surrounding the availability of these materials means that it is now viable for the nuclear industry to explore options with regards to successor cements, many of which are now in reliable and continuous supply, with demonstrable records of performance in experimentation and construction. This is an opportunity for investigation into cements that may not only be more sustainable, and therefore more likely to be easily obtainable for decades to come, but also those that may offer enhanced performance characteristics.
This thesis aims to build upon the knowledge base of two potential cements for nuclear applications: calcium sulfoaluminate and metakaolin geopolymers. In collaboration with the UK nuclear industry, two large scale series of commercially available grout trials were conducted, followed by an extensive review of the phase assemblage in the context of the unique requirements for the encapsulation and/or immobilisation of radioactive waste. This represents a significant step in the maturity of both of these systems and their potential adoption by the industry, bridging the gap between small scale laboratory experiments and full-scale mix trials. The robustness of both systems was proved on a 90-day timescale and beyond, with a range of mixing variables appropriate for nuclear applications.
Following this, the technology readiness level of each cement is considered, as well as the likelihood of these cements being adopted by the wider cement market so much as to ensure the security of their supply. Not only is this assessed in terms of the maturity of the technology, but also a discussion is held about the adoption of Portland cement almost two centuries prior, and the behaviour of heavy industry, particularly towards emerging technologies. Any similarities may then be drawn to better understand how the cements market might react in the future to these alternative binder systems. Both of these cement systems are actively being researched and have been used successfully. Calcium sulfoaluminate is of particular interest to the construction industry, with an increasing case portfolio of rapid set and strength gain applications, and a more familiar production and application method.