“…While GPs can be synthesized with no Ca in the system, such GPs require curing at elevated temperatures of at least 50 °C. This restricts their practical application in the field of civil engineering but not necessarily in wellbore construction. , In GP systems based on precursors that do not contain Ca, Ca is commonly incorporated as an additive to eliminate this need for elevated curing temperatures, for example, through the addition of OPC, GGBFS, class C fly ash, calcium hydroxide, calcium carbonates, calcium aluminate cement, or natural calcium silicate materials. ,,,− In fact, many argue that the coexistence of N–A–S–H and C(−A)–S–H gels leads to the reduced porosity/permeability, reduced water adsorption, increased density, stronger networks benefiting from composite binding phases, and higher compressive strengths of the GP system. ,,,, For instance, the positive impacts that Ca can have on GP gel structures is demonstrated by Yang et al, who reported the presence of amorphous homogeneous N–C(−A)–S–H in fly-ash-based GPs modified with slags, where calcium contributes to the formation of a more compact microstructure and consequently higher compressive strengths compared to unmodified fly-ash-based GPs. , …”