Theoretical principles for obtaining gypsum-free Portland cement (GFPC) modified by organic-mineral additives were investigated. Gypsum-free Portland cement was improved by rational selection of the chemical additives which act as hardening accelerators, plasticizers and setting retarders. The hydration and structure formation processes as well as building-technical properties and running ability were established. The influence of alkaline metals carbonates as hardening accelerators on pH of a liquid phase, hydration degree in the alkaline systems as well as features of plasticizers action in constitution complex chemical additives were investigated. The possibility of speed regulation of GFPC early structure formation by introduction setting retarders which are replacing the effects of gypsum was determined. There were investigated the characteristics of the phase structure and microstructure of the artificial cement stone on the basis of gypsum-free Portland cement modified by the complex chemical additives and fine-dyspersated lime stone. Early structure formation is characterized by hydroaluminate hardening type with formation of metastable carbonate replaced by AF-phase followed by structurally active hexagonal AFm-phase C4A.C02-11H20.
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