Chloride ingress rate and threshold content, as determined by the ‘Integral’ test method, in concrete with several w/c ratios in saturated and unsaturated conditions

Abstract

The ‘integral’ test method aims at the simultaneous determination of the chloride migration rate and chloride threshold content. This information is required for durability performance design of reinforced concrete structures in the marine environment. Standard tests are generally designed to be applied on saturated samples to improve their repeatability and reproducibility, but this condition differs from the actual conditions of depassivation in structures in service. This paper compares results of the ‘integral’ test method applied on concrete made with ordinary Portland cement and a water-to-cement ratio ranging 0.35–0.50, preconditioned for full saturation and a saturation degree of 77%. Results are contrasted with concrete properties commonly associated with its performance concerning chloride ingress. The variation in the saturation degree in the range 77–100% showed a greater effect on the chloride ingress rate than in the chloride threshold content. The determined chloride threshold decreases with increasing w/c ratio.