Investigation of sulfates effects in perlite-based geopolymer

Abstract

Condition deterioration of the concrete, especially in corrosive environments, is one of the most common imperfection and disadvantages of reinforced concrete structures. Sulfates' main damages are expansion and loss of strength. Geopolymers are one of the newest structural materials that have been widely developed in recent years for use in sustainable designs. Geopolymers are environmentally friendly and considered as green materials since they are effective in sustainable and eco-friendly material design concept. One of the most important matters in the sustainability of structural materials is their resistance against sulfates. So far, the durability of perlite-based geopolymers against sulfates and acids has not been investigated. In this research, the fineness influence, curing conditions, duration of maintaining in the sulfate environment at different weight percentage in solution (i.e., 2.5, 5, 7.5, and 10%) have been investigated. Compressive strength and microstructure changes of geopolymer samples have been assessed in this research. As a result, optimum increase in perlite fineness causes increase in compressive strength and durability of samples against sulfate attack. Also, samples that have been cured by autoclave method have better mechanical properties and better durability. It is hoped that by filling these deficiencies and gaps, a positive step can be taken to accelerate attempts for finding a suitable replacement for ordinary Portland cement. © 2019 fib. International Federation for Structural Concrete