Influência do silicato de sódio neutro na degradação de pastas de cimento Portland submetidas ao ataque por ácido sulfúrico

Since that wastewater treatment plants are exposed to microorganism-induced corrosion due to sulfuric acid attack (H2SO4), this study aimed to test neutral sodium silicate (Na2SiO3) as a mitigating solution to the acid attack. Specimens were molded with different contents of Na2SiO3 (0%, 1%, 5% and 10%), and with 35% of CP-V ARI Portland cement replacement for class C fly ash. Finally, the samples immersed in sulfuric acid solution were compared with those immersed in saturated limewater. In the results, it was observed that the water absorption and the voids ratio depended on the development of the microstructure and the reaction kinetics between cement and H2SO4, expressed as the chemical recombination between sulphate and portlandite ions. The microstructural degradation was proven by the FT-IR analysis.