ABSTRACT
The propagation of a crack i n concrete involves a great deal of microcracking, much of i t occurring i n the highlystressed region ahead of the apparent crack t i p . According to Bazant and Oh (1983), because of the heterogeneity of concrete, i t behaves i n a nonlinear fashion i n a r e l a t i v e l y large region adjacent to the apparent fracture front; the fracture process zone represents that part of the n o n l i n e a r zone i n which the m a t e r i a l undergoes progressive microcracking, manifested by s t r a i n softening behaviour. On the other hand, Shah (1988) has equated the fracture process zone as the region of p r e c r i t i c a l crack growth (or slow crack growth) which precedes the maximum load. Thus, while there i s general agreement that a fracture process zone exists i n concrete, there i s no agreement on exactly what constitutes a "process zone" i n cementitious materials.
