Rapid chloride migration

The next step is to test one or more of the selected concrete compositions using a compliance test that determines the chloride-penetration resistance. DuraCrete has adopted the rapid chloride migration (RCM) test for this purpose [21,25], which is a short-term test based on acceleration of chloride penetration by an electric field. 

J ci,o = chloride-penetration resistance determined from compHance tests (y/mm ), i. e. the inverse of the diffusion coefficient from the rapid chloride migration test (RCM),... 

Rapid-Chloride-Migration test. The chlorides in sea water do not attack the mortar itself. However, exceeding the critical chloride content in the mortar near the steel surface might lead to a high corrosion risk. In that case, a localized corrosion occurs, which might spread quickly to the center of the steel tower. 

By adding polymer dispersions and thereby decreasing the permeability, a further reduction of the chloride migration coefficient can be achieved. The rapid chloride migration test is a quick tool to test the chloride resistance by applying a voltage [1]. In relation to the depth of cover, the risk for corrosion of the steel surface can be estimated in terms of time. 

The resistance of the concrete against chloride penetration was mainly tested by use of the Rapid Chloride Migration (RCM) method [6] and electrical resistivity measurements based on the two-electrode method [7], The testing was carried out on 50 mm cut slices from 0100 x 200 mm concrete cylinders, and the concrete samples were mainly cured in water with a temperature of 20 2 C and tested at regular intervals of up to 90 days. In addition, some samples from two of the concrete mixtures (PO O and Pl. O) were wrapped in plastic sheeting after demoulding and stored in air with a temperature of 20 2°C until time of testing. 

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