National Research Conseil national I N21d Council Canada de recherches Canada Construction construction A Procedure for Determining the Thermal Diffusivity of Materials Thermal Diffusivity of Materials

a p l a q u e s chaudes. On f a i t v a r i e r l a t e m p e r a t u r e d e c e s p l a q u e s R un t a u x c o n s t a n t . On suppose q u e l a c o n d u c t i v i t e thermique, l a c h a l e r l r s p ' e c i f i q u e e t l a m a s s e v o l u m i q u e d u m a t 6 r i a u s o n t c o n s t a n t e s a u x t e m p 6 r a t u r e s A ' ----' " . ABSTRACT The thermal difisivity of a solid material can be determined using pairs of identical specimens prepared for a thermal conductivity determination in a Guarded Hot Plate apparatus (ASTM C-177). Specimens are placed one on top of the other with a temperature sensor between them, and the pair is placed between the heat-sink plates of a Guarded Hot Plate apparatus. The temperature of these plates is varied at a constant rate. The thermal conductivity, specific heat and density of the material are assumed to be constant over the range of temperature used for the test. For a pair of granite slabs, at a mean temperature of 8OC, the thermal diffusivity is 8.49 x lo-' m2/s Z!C 0.02 x lo-' m2/s