Introducing a novel optimised binder activator with Redcar mudstone feedstock in the UK for geopolymer cement formation

This paper evaluates Redcar Mudstone (RM), a type of shale rock, as a potential geopolymeric binder for cement
production, highlighting its preparation through milling and calcination, followed by blending with an alkali
activator. The study utilises an L8 orthogonal array matrix to determine the optimal mix design based on
maximum compressive strength. Mechanical tests reveal that sodium-activated RM serves as a viable feedstock,
producing cement comparable to or better than other mineral-based feedstocks, achieving a maximum mean
compressive strength of 71.98 MPa. The mix optimisation process indicates the RM to alkali ratio and the sodium
silicate to sodium hydroxide ratio as critical factors in developing this geopolymer cement. Results show a
significant presence of aluminosilicates in their oxidised state, essential for the geopolymerisation process,
aligning with all mineralogical analyses. The competitive results of this cement experimentation with Ordinary
Portland Cement (OPC) and other geopolymers underscore its potential. This research underscores the environmental and strength performance advantages of RM derived geopolymers, suggesting their potential as an
effective waste valorisation method and a green alternative in cement production, driven by the global push to
reduce CO2 emissions and the extensive research on geopolymers and innovative binders.