Leaching experiments were performed over several weeks on cylinders of OPC mortars, previously cured 28 days, in acidic conditions.The pH was maintained constant at 2, 4 or 6 with the addition of H2SO4 at 30℃ during 28 days.A temperature of 30℃ instead of 20℃ enabled us to accelerate the rate of leaching without modifying the mineralogical phase assemblages.The aqueous solution was analyzed for calcium, silicon,aluminium and iron elements by ICP-OES.Moreover, at the end of the experiment, the microstructure of the OPC mortar was observed by SEM on polished section.The results presented as the cumulated amounts of chemical elements leached as a function of time, clearly demonstrated that silicon, aluminum and iron in addition to calcium can be released markedly after an induction period but in larger amounts at a lower pH.A greater release of these elements is associated to a larger thickness of the degraded zone that is depleted in calcium.Indeed significant amounts of low solubility phases such as silica and alumina gels are found in the degraded zone that was very porous.Thus the dissolution rate of these low solubility phases that have a large surface area in contact with aqueous phase in the degraded zone due its large porosity, can bring a contribution to the rate of leaching of these chemical elements.Moreover for longer leaching times, the volume of the degraded zone increased relatively to the total volume of the sample and as a consequence, the efficiency of H+ ions to solubilise the minerals decreased.Thus the degradation of the cement paste of the mortar is less than what would be expected on the basis of short term leaching experiments mostly based on the leaching of calcium ions.A leaching coefficient (LC) was thus proposed to follow the efficiency of H+ ions as a function of time.