sentences:  The American patent application was filed in 1984 and the patent US 4,509,985 was granted on April 9, 1985 with the title 'Early high-strength mineral polymer'.The replacement of a certain amount of MK-750 with selected volcanic tuffs yields geopolymer cement with better properties and less CO2 emission than the simple slag-based geopolymer cement.Later on, in 1997, building on the works conducted on slag-based geopolymeric cements, on the one hand and on the synthesis of zeolites from fly ashes on the other hand, Silverstrim et al.