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Документ Feasibility of incorporating SO42--ions in zeolite-like matrices based on alkaline aluminosilicate binders(Elsevier BV, 2023-08) Krivenko, Pavlo; Rudenko, Igor; Konstantynovskyi, Oleksandr; Vaičiukynienė, DanutėFactors determining minimization of the influence of sulfate environments on concrete and risk of corrosion of embedded steel reinforcement have been analyzed. Coatings based on alkaline aluminosilicate binders were proposed to prevent transport of the sulfate ions into concrete. The formation of water resistant zeolite-like matrices on the alkaline aluminosilicate binder of the Na2O-K2O-Al2O3-SiO2-H2O system at 20 ± 2 ◦C can be provided by the use of calcium-containing modifying additives. Optimized molar ratios between oxides of binder constituent were SiO2/Al2O3 = 4–5 and K2O/(Na2O + K2O) = 0.15–0.30. The results of the study show that the speed of incorporating sulfate ions in cement matrix of binder from the sulfate environment is dependent upon a cation and ranks as follows: (NH4)2SO4 > MgSO4 > Na2SO4 > CaSO4. Complete protection of concrete against the penetration of sulfates can be reached when the developed coating is applied in a thickness of 3 mm.Документ Enhancement of alkali-activated slag cement concretes crack resistance for mitigation of steel reinforcement corrosion(EDP Sciences, 2020-04) Krivenko, Pavlo; Petropavlovskyi, Oleh; Kovalchuk, Oleksandr; Rudenko, Igor; Konstantynovskyi, OleksandrThe paper is devoted to mitigation of steel reinforcement corrosion in alkali-activated slag cement (further, AASC) concretes, based on soluble sodium silicates (further, SSS’s), obtained from high consistensy concrete mixes. Enhancement of AASC fine concretes crack resistance due to modification by complex shrinkage-reducing additives (further, SRA’s) based on surfactants and trisodium phosphate Na3PO4.12H2O (further, TSP) was proposed for mitigation of steel reinforcement corrosion. SSS’s were presented by sodium metasilicate (silica modulus 1.0, dry state) and water glass (silica modulus 2.9, density 1400 kg/m3). In case of sodium metasilicate the application of SRA composition “ordinary portland cement clinker – TSP – sodium lignosulphonate – sodium gluconate” provides enhancement of crack resistance starting from early age structure formation with restriction of drying shrinkage from 0,984 to 0,713 mm/m after 80 d. The effect is caused by reduction of water and by higher volume of crystalline hydrates. In turn, SRA presented by compositions “TSP – glycerol” and “TSP – glycerol – polyacrylamide” provide enhancement of AASC fine concretes fracture toughness during late structure formation with increasing ratio of tensile strength in bending to compressive strength up to 37 – 49 % if compare with the reference AASC when water glass is used.Документ Enhancement of alkali-activated slag cement concretes crack resistance for mitigation of steel reinforcement corrosion(EDP Sciences, 2020-04-22) Petropavlovskyi, Oleh; Kovalchuk, Oleksandr; Krivenko, Pavlo; Rudenko, Igor; Konstantynovskyi, OleksandrThe paper is devoted to mitigation of steel reinforcement corrosion in alkali-activated slag cement (further, AASC) concretes, based on soluble sodium silicates (further, SSS's), obtained from high consistensy concrete mixes. Enhancement of AASC fine concretes crack resistance due to modification by complex shrinkage-reducing additives (further, SRA's) based on surfactants and trisodium phosphate Na3PO .12H2O (further, TSP) was proposed for mitigation of steel reinforcement corrosion. SSS's were presented by sodium metasilicate (silica modulus 1.0, dry state) and water glass (silica modulus 2.9, density 1400 kg/m3). In case of sodium metasilicate the application of SRA composition "ordinary portland cement clinker - TSP - sodium lignosulphonate - sodium gluconate" provides enhancement of crack resistance starting from early age structure formation with restriction of drying shrinkage from 0,984 to 0,713 mm/m after 80 d. The effect is caused by reduction of water and by higher volume of crystalline hydrates. In turn, SRA presented by compositions "TSP - glycerol" and "TSP - glycerol - polyacrylamide" provide enhancement of AASC fine concretes fracture toughness during late structure formation with increasing ratio of tensile strength in bending to compressive strength up to 37 - 49 % if compare with the reference AASC when water glass is used.