Relation between durability and mechanical properties on glass fiber reinforced slag-based geopolymer

This work seeks to improve the understanding of the durability of pure slag-based geopolymer composites containing glass fibers. Degradation by attack of saline mist, simulated by the salt-spray essay, was carried out for a period of 30 days. The test simulates the conditions found in the sea and nearby environments. The chamber works at relative humidity ∼97%, by nebulizing sodium chloride solutions with a concentration of 5% at 35+2 °C, solution pH between 6.5 and 7.2. After the cycle, the loss of mass and the compressive strength of the specimens were measured. The efflorescence formation in slag-based geopolymers is also assessed in this study to provide a better understanding of the effect of the synthesis parameters. It is noted that physical and chemical properties of geopolymers, and environmental exposure conditions can affect the rate of efflorescence formation. Besides the control set group, two different solutions to prevent efflorescence were tested, MgO and an efflorescence reduction agent from Sika®. The work aims to examine the effect of efflorescence formation on mechanical properties, through flexural and compressive strengths. A compromise between durability and mechanical properties was found for specimens enriched with 2% of efflorescence reduction agent.