Rapid Chloride Permeability Testing of Silica-Fume Concrete

For long-lasting, reinforced-concrete structures exposed to the environment, low permeability concretes are required. ASTM C 1202 (Electrical Indication of Concrete's Ability to Resist Chloride Ion Penetration) is a rapid test that indirectly measures the permeability of concrete. The results of the rapid test have been related to direct measurements of permeability (e.g., ponding test) and have been found to be useful and valid provided that possible interferences are accounted for. For comparisons between tests, similar concretes should be tested at similar ages. The addition of silica fume results in a reduction in the permeability of concretes. The rapid test has been able to provide information on relative permeability of concretes with or without silica fume. This finding has been confirmed by the results of the extended ponding test.