ABSTRACT
Fracture of refractories is considered from the traditional strength point of view
and from the perspective of fracture mechanics. Strength and fracture toughness
are related through the aggregate sizing of refractories, which illustrates the
importance of the microstructural aspects of the refractory aggregate to the
strength. The J-integral analysis methodology and the wedge-splitting exper-
imental technique are both reviewed as they are useful to address the nonlinear
load-displacement character of refractories. The latter is associated with the con-
cept of a rising R-curve, which is discussed from the phenomenological point of
view. The rising R-curve is directly related to the refractory aggregates through
toughening mechanisms that are active in the crack process zones, both in front of
and behind an extending crack.
