Influence of different water types on the physical and mechanical properties of gypsum

evaluate if gypsum mixed with different water types, with their different compositions influence the dimensional change, surface roughness and compressive strength of type IV and V gypsum specimens. Methods: Sixty specimens were fabricated from metal matrices and divided into six groups (n=10) according to the used type of gypsum and water: G1, G2 and G3 type IV gypsum and tap, mineral and distilled water, respectively; G4, G5 and G6 type V gypsum and tap, mineral and distilled water, respectively. Water/powder ratio followed the manufacturers recommendations (19 mL/100 g) in all groups. The same specimens were used for all tests. A micrometer dial evaluated the dimensional change. The surface roughness of three random points was determined with a rugosimeter; a universal testing machine performed the compressive strength test. The data were subjected to analysis of variance (ANOVA). Results: There was no statistically significant difference (p>0.05) between the three types of water in the studied variables. There was statistically significant difference (p<0.05) between the gypsum mixes for the dimensional change variable. Conclusions: The different water types, with their different compositions, did not influence the analyzed physical and mechanical properties