“…Partial replacement of cement with other materials allows for the production of hybrid cement-geopolymer concrete. Earlier it was shown that Portland cement can be partially replaced by various materials [ 14 ], such as a metakaolin (MK) [ 18 ], which improves the properties of hybrids, their workability and durability, and reduces the environmental impact of the cement industry [ 19 , 20 , 21 ]. Further, fly ash and slag, due to their properties being similar to cement, are also suitable alternatives to its partial replacement [ 22 , 23 ].…”