Effect of different curing conditions on the compressive and flexural properties of Plaster of Paris

Gypsum plaster is often used when modelling rock and rock structures. As such, it is important that the mechanical properties of the plaster models are known and are consistent. In this study, uniaxial compressive tests (UCS) and 3-point bending tests were conducted to investigate the effect of different curing conditions on the compressive and flexural properties of Plaster of Paris specimens. The variations in curing condition consisted of curing time (1 day, 3 days, 5 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 8 and 12 weeks) and curing environment (room temperature and in a 45°C oven). It was found that the plaster placed in the oven possessed greater overall uniaxial compressive strength than its room condition counterpart, and both groups experienced an increase in UCS over time, reached a maximum but then weakened with further cure time. In a similar finding the plaster cured in the oven had greater flexural strength than the plaster cured under room conditions.