Studies at EPFL [10], [11] have shown that a kaolinite content of only about 40% in a mixture of LC 3-50 (50% ground clinker, 30% calcined clay, 15% limestone, 5% gypsum) is sufficient to give mechanical properties comparable to the reference plain Portland cement from about 7 days (EN 196-1 mortar bars w/c = 0.5, sand/cement = 3 …