ПРОТИДІЯ ДИФУЗІЇ ІОНІВ МОРСЬКОЇ ВОДИ В СТРУКТУРУ ШЛАКОЛУЖНОГО ЗАЛІЗОБЕТОНУ

Abstract

Application of alkali-activated slag cement concrete (further, AASC concrete) for structures, operated in seawater, is relevant due to their increased resistance in aggressive environments. High consistency fresh concrete causes negative changes in structure of hardened concrete which ensure increase of aggressive ions diffusion. Thus, the means to prevent corrosion of steel reinforcement in plasticized AASC concrete are actual for investigations. It has been shown, that modification of plasticized AASC concrete by complex of additives including portland cement, calcium aluminate cement, trisodium phosphate (Na3PO4
.12H2O) and clinoptilolite enhances protection of steel reinforcement. By physical-chemical methods it was concluded that specified complex restricts diffusion of Cl and SO4 2-ions in modified AASC concrete due to chemical adsorption by gel-like phases, chemical binding with formation of Kuzel`s salt 3CaO∙Al2O3∙0,5CaCl2∙0,5SO4∙10H2O and chlorapatite Ca5(PO4)3Cl as well as occluding by zeolite-containing admixture and hydrates presented by alkaline hydrosilicates. This phenomena was confirmed by qualitative reactions on Cl and SO4 2- ions in concrete structure, as well as by mass losses of steel bars embedded in AASC concrete and reached out after 9 months storing in sea water.