Mechanical behavior and cracking pattern analysis of geopolymer composites reinforced with sisal fibers

Geopolymers are materials that present high initial compressive strength, in addition to presenting resistance to high temperatures, sulfates and acids. However, it is a ceramic material with brittle behavior. To compensate for such fragility, several types of fibers have been used. In the present work, geopolymer composites reinforced with sisal fibers were produced and tested under direct tension. Two different distributions of continuous and aligned fibers were evaluated: fibers distributed longitudinally and fibers distributed at 45°, in both cases a volume fraction of 3% of fibers was used. The deformation and cracking behavior were analyzed by the Digital Image Correlation (DIC) technique. The results found were compared with other results present in the literature, demonstrating similarity with the studies analyzed. The composites presented strain hardening behavior with the formation of multiple cracks, with an increase in resistance after the formation of the first crack. Composites with longitudinally distributed fibers showed better performance, demonstrating that the performance of composites depends on the orientation of fiber distribution in relation to the applied load.

Keywords:
Geopolymer composites; sisal fibers; geopolymers; digital image correlation (DIC)