COMPARISON BETWEEN THE MECHANICAL AND DIELECTRIC STRENGTH DISTRIBUTIONS FOR HARDENED GYPSUM

Hardened gypsum is chosen as a simple model of hardened cement materia ls and an analogy between the mechanical and dielectric strength distr ibutions is investigated. Both of the strengths are evaluated in terms of Weibull statistics and a two-parameter Weibull function is adopted for both of the strength distributions. Both plots show good coincide nce which is independent of the water content used during the mixing o f hemihydrate gypsum powder for hardening. The hardened gypsum sheets made with 70 wt% of water, have mechanical and dielectric strength dis tributions that show two different behaviours in the Weibull plots, ho wever, both the plots agree with each other. From our results, it is c oncluded that the mechanical strength distribution of hardened gypsum can be evaluated in terms of the dielectric strength distribution, whi ch can be easily measured from a breakdown test.