The presence of chloride ions, at the surface of embedded steel in concrete, is a cause of reinforced concrete degradation. Cracks accelerate this process by allowing chloride ions to reach the steel without traveling through the relatively impermeable concrete. A common repair technique is to fill cracks with an epoxy or methacrylate polymeric material. The extent to which these crack filling materials penetrate and seal the crack from water containing chloride ions is unknown. Furthermore, the effect the crack filler has on the service life of the structure has not been studied. Simulations suggest the crack filler has a pronounced effect on the chloride distribution around the crack but are highly dependent on assumptions made regarding the crack filler/concrete interface. The o b je c tiv e of this study is to determine the extent to which epoxy and m ethacrylate crack fillers seal a crack and to improve upon existing service fife models by incorporating the effects of a polymer-filled crack on chloride ion concentration. Microbeam X-Ray Florescence Spectrometry (pXRF) is used to measure chloride ion ingress and validate a model of chloride ion concentration derived from a mass balance. Neutron tomography is used to observe the crack filler contained within the crack, in three-dimensions, and to estimate the penetration of the crack filler into the m ortar, through the crack face.