Effect of inorganic coating-modified steel reinforcement on properties of sulfoaluminate cement-based non-autoclaved aerated concrete slabs subjected to sodium chloride attack, sodium sulfate attack, and freeze-thaw cycles

Abstract

To address the corrosion challenges associated with steel reinforcement in non-autoclaved aerated concrete slabs (NAACSs), zinc silicate-potassium silicate modified with aluminum powder and muscovite-potassium silicate modified with zinc powder were employed to modify steel reinforcement, while novel NAACSs based on sulfoaluminate cement were fabricated. The degradation trends in physical characteristics, mechanical properties, and morphological changes of the NAACSs were investigated under the erosion effects of Cl, SO₄², and freeze-thaw cycles. The results demonstrated that the mass loss and relative dynamic modulus of elasticity reduction of the NAACS containing muscovite-potassium silicate modified with zinc powder were reduced by up to 42.8 % and 26.3 %, respectively. Moreover, the bond strengths of the NAACSs were 48.1 %-92.3 % higher prior to erosion and 12.5 %-32.1 % higher post-erosion, respectively. The effects of various erosion conditions on bond strength were ranked as follows: SO₄² > freeze-thaw cycles > Cl. Both inorganic coatings effectively inhibited the corrosion of steel reinforcement by erosion media, thereby enhancing the durability of the NAACSs.