"In... 1983, with Joseph Sawyer as head of Lone Star's research laboratory... I started to develop early high-strength geopolymeric binders and cements based on based on both geopolymeric and hydraulic cement chemistries. Within one month Lone Star Industries Inc. formed the development company, PYRAMENT... exclusively dedicated to... this new class of cement. ...It was discovered that the addition of ground blast furnace slag, which is a latent hydraulic cementitious product, to the poly(sialate) type of geopolymer, accelerates the setting time and... improves compressive and flexural strength. The first Davidovits and Sawyer patent was filed in... 1984... The corresponding European patent... in 1985... and these... disclose our preliminary finding...of 1983. Geopolymer cements are acid-resistant cementitious materials with zeolitic properties that can be applied to long-term containment of hazardous and toxic wastes."