Durabilidade de compósitos cimentícios reforçados com fibras de PVA frente ao ataque de sulfato de sódio e de magnésio

Abstract

The deterioration of structures in Civil Engineering has generated concerns about durability, leading to the search for innovative materials, as alternatives for repairs and reinforcements. Strain Hardening Cementitious Composites (SHCC) emerges as a solution with improved mechanical characteristics, elevated toughness, and crack control. However, its behavior in sulfate environments has knowledge gaps due to lack of documentation and regulations. This study addresses the behavior of SHCC after aging up to 1092 days in sodium and magnesium sulfate, using samples in water curing with calcium hydroxide for the same period, as reference. This study used 3 variations of SHCC mixtures, with different contents of fly ash and water. Axial compression and four-point bending tests were carried out to evaluate the mechanical properties, and absorption, porosity, density, expansion and SEM tests, to study the physical properties. The results showed that the fiber-reinforced cementitious composite mixtures performed well when exposed to sodium sulfate, because presented similar properties with the reference samples. After aging in magnesium sulfate, all mixtures finished the tests with significant changes in water absorption, porosity, expansion, compressive strength, first crack stress and maximum stress and deflection, after bending tests.