Comparison and study of mechanical and physical properties of metakaolin reinforced gypsum composite

This study investigated the effect of creating a composite of gypsum with metakaolin as well as the physical and mechanical behavior of the produced composites. For this purpose, gypsum composites were prepared with 2.9, 4.8, 6.5, and 9 wt.% metakaolin in 100 g of gypsum and a constant content of water. To determine the mechanical properties of the composites, the compressive strength test was used and the porosity, water absorption percentage, and bulk density of the composites were obtained using the Archimedes method. The results showed that the porosity was reduced by adding up to 7 wt.% metakaolin to the gypsum specimens, it increases the compressive strength by 41% and also raises the Young's modulus of gypsum by 121%. Scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) was employed for the microstructural evaluations. The EDS-SEM observations showed the presence of Al and Si elements in the fracture zones. The presence of metakaolin elements at one point increases resistance in that area. Metakaolin-reinforced gypsum composites can be used in boards and panels.