ITZ IN PLAIN AND FIBER CONCRETE

摘要

The ITZ around aggregate particles and fibers results from size segregation of cement in the fresh state. The paper introduces the relevant stochastic concepts of heterogeneity and of representative units. It discusses the relationship between sensitivity to structural details and the impact on experimental design. The ITZ packing structure can be investigated analytically, by experiments and computer simulation. Theoretical and most of the computer simulation approaches are based on random generator principles. Experiments are liable to serious biases. The paper stipulates that size segregation under such conditions will be limited to an interface zone with a thickness equal to maximum grain size. Computer simulation by SPACE, which relies on a dynamic stage, reveals the extent of the ITZ to depend on the afore-mentioned sensitivity. The paper offers simulation material showing the ITZ packing structure at aggregate and fibre surfaces to be quite similar.