Global quantitative monitoring of the ion exchange balance in a chloride migration test on cementitious materials with mineral additions

Abstract The concrete pore solution changes during chloride transfer due to the species leaching and the dissolution/precipitation of compounds. The latter could affect the material porosity and the chloride diffusion coefficient. In order to quantify these changes, the global movement of species was monitored on blended cement materials during a chloride migration test. Compartment solutions and sample pore solutions were analyzed in order to quantify the ion exchange balance. Two migration test protocols were carried out using (i) NaOH, KOH and NaCl, and (ii) synthetic seawater and synthetic pore solution. The use of slag reduces the free chloride in the porosity by about 9 times. For the Portland cement material, a precipitation of 0.3%wt of Na, 0.6%wt of K and 1%wt of Cl participated in a porosity clogging of 60%. Finally, the materials with mineral additions reduce the portlandite dissolution during chloride transfer and the calcium leaching phenomena up to 26%.