The effect of CSF on the mechanical behavior of the steel-concrete bond, and on the
microstructure of the steel-cement paste transition zone was studied by several
investigators [GjΦrv et al., 1990; Bentur et al., 1987; Cheg-Yi et al., 1985]. The
addition of CSF up to 10% by weight of cement showed an improving effect on the
pullout strength, especially in the high compressive strength range of concrete. It also
affected the morphology and microstructure of steel-cement paste transition zone. Thus
aggregate matrix transition zone, which is usually porous and weak in normal concrete,
became very compact in presence of silica fume.