Research has been conducted towards the development of a compressive t
est method more suitable than present procedures for use on advanced c
eramics with extremely high compressive strength. A dumb-bell-shaped s
pecimen is proposed as an edge-effect-free shape, and test equipment w
ith a self-aligned system is suggested to estimate accurately the comp
ressive strength. Experimental results for some structural ceramics in
dicate the following: (1) the columnar specimen prescribed in the Japa
nese Industrial Standards has edge effects, whereas a dumb-bell-shaped
specimen has no edge effect and shows higher strength than the column
ar specimen; (2) acoustic emission events are detected at an early sta
ge of the compressive load, and the behaviour coincides with the initi
ation of the crack propagation under compression; (3) an isolated crac
k on the specimen surface of ceramics with a fine matrix has little in
fluence on compressive strength.