Chloride Ingress into Reinforced Concrete Sustaining In-service Loads: a Study Trying to Relate Chloride Diffusion Coefficient to Stresses or Bending Moments in Concrete Subjected to Loads

The objectives of this study were to investigate the effect of sustained load on chloride ingress into concrete and to examine the reliability of spraying a AgNO3 solution onto concrete as a quick method to determine chloride penetration. An experimental program was carried out, in which a small-scale RC slab was subjected to wet and dry cycles with a saturated chloride solution while sustaining static service loads. The concrete slab was cast with three strips of different w/c ratios to represent diff- erent field condition. Supports were located to create both positive and negative moment regions in the top mat reinforcement of the slab. Chloride diffusion coefficients were obtained from the data obtained from spraying AgNO3 and titration of core samples taken at different sections of different stress levels at three time intervals, each of them after a wet/dry cycle of 90 days. The comparison between both sets of data reveals that the diff- erences diminish as the time of exposure increases. The chloride diffusivity along the span of the slab, relative to that of an unstressed section, was related to the applied bending moment.