Supersulfated Cements: A Review Analysis of the Features of Properties, Raw Materials, Production and Application Prospects

Abstract

Currently, research aimed at developing alternative binders that can partially or completely replace Portland cement is relevant. At the same time, the priorities are minimal impact on the environment (including dust and CO2 emissions), energy saving, and rational use of natural resources through the disposal of man-made waste. Extremely promising from these positions are supersulfated cements (SSC), which consist of 80–85 % of the aluminosilicate component; 10–20 % from the sulfate component and 3–5 % alkaline activator. The traditional aluminosilicate component for SSC is granulated blast furnace slag (BFS), however, due to the removal of requirements for the content of aluminum oxide in its composition (not lower than 14 %), it has become possible to partially or completely replace it with other technogenic or natural aluminosilicate products. Instead of natural gypsum-containing raw materials, technogenic ones (phosphogypsum, desulfurization gypsum) are increasingly being considered as a sulfate component, both in the form of dihydrate and in the form of anhydrite and hemihydrate. Due to this composition and the possibility of using waste as the main components, this type of cement is characterized by significantly lower CO2 emissions into the environment and energy costs for production compared to Portland cement. The article describes the features of the hydration mechanism of SSC, which determine its main properties: low heat generation, high resistance in sulfate and chlorine environments, acid resistance. Disadvantages are considered - long hardening times, reduced frost resistance, high carbonization rates. Ways to combat the shortcomings of SSC and prospects for further research are described