Optimisation of rheological parameters, induced bleeding, permeability and mechanical properties of supersulfated cement grouts

Abstract

Presenting a promising option that could be used to encapsulate nuclear waste material for disposal, supersulfated cement (SSC) is, again, receiving wide attention among research community as a cementitious system that has noteworthy properties. It is also an environmentally friendly cement since it is mainly composed of ground granulated blast furnace slag (GGBS) that is activated by a sulphate source such as gypsum, hemihydrate or anhydrite. Although there is some research on SSC, little research work has focused on modelling the effects of the various parameters using a statistical approach which is the aim of this paper. The effect of dosages of GGBS, anhydrite (ANH) and water-to-binder ratio (W/B) on the fresh and rheological parameters, induced bleeding, permeability, compressibility, and compressive strength of supersulfated grouts was investigated. Then, statistical models and isoresponse curves were developed to capture the significant trends of the tested parameters using factorial design approach. The models suggested that that W/B had significantly higher influence on most of the parameters tested while the influence of GGBS and ANH and their interactions varied depending on the parameter in question. The findings of this study show the importance of understanding the role of and optimising the relevant key factors in producing SSC fit-for-purpose. The statistical models developed in this paper can facilitate optimizing the mixture proportions of grouts for target performance by reducing the number of trial batches needed.