Kyrychok O. Effective concretes for winter concreting

Subject of researches: concrete with complex antifreeze admixture on base of sodium thiocyanates and thiosulfates; purpose - development of concrete works at negative temperatures, using effective concretes with complex antifreeze admixture on base of sodium thiocyanates and thiosulfates; methods - review and analysis of literature, experimental researches, analysis and introduction of research results to production; results - according to research results, got in thesis, effective concrete with complex antifreeze admixture on base of sodium thiocyanates and thiosulfates is proposed. It is characterized by capacity to be used at negative temperatures of hardening; it is suggested to use method of accelerated determination of corrosion resistance of reinforcement in concrete in the presence of sodium thiocyanates and thiosulfates; newness - it is theoretically grounded and experimentally proved that it is possible to obtain effective concretes of up to B 45 compressive strength grade with complex antifreeze admixture on base of sodium thiocyanates and thiosulfates; it is indicated that processes of reinforcement corrosion in concrete have wave-like behavior; using of complex methods (electrochemical and weight) determined limiting content of sodium thiocyanates and thiosulfates in concrete without worsening of its protective properties relatively to steel reinforcement, created by different methods (hot-rolled, cold-drawn); it is stated (using complex of physical-chemical research methods) that components of complex antifreeze admixture create protective cover of solid solutions of the following content: 3CaOoFe2O3oy XonH2О, where Х - CaSO4, Ca(NO2)2, Ca(CNS)2 on reinforcement as a result of oxidation-reduction reactions during interaction with water, cement minerals, oxygen and reinforcement; it is stated that concrete with complex antifreeze admixture on base of sodium thiocyanates and thiosulfates is characterized by fine-grained compact-grained microstructure; it is introduced - concrete mixes on base of developed effective complex antifreeze admixture were used in industrial conditions (JSC "Rivne region RCA 15698") for concreting of foundations. Using of the given admixture helps to realize concrete works in conditions of negative temperatures and to create effective concretes. Economic effect, got by introduction of effective concrete with complex antifreeze admixture, is 2262 hryvnas for 290 m3 of concrete.