Sulfate ingress and microstructural changes in cement pastes at early age

XIII International conference on Durability of Building Materials, SAO PAULO, BRESIL, 02-/09/2014 - 02/09/2014External sulfate attack is mostly studied on saturated matured samples. These laboratory investigations often focus on the expansive mechanisms altering the mechanical macroscopic properties of the cementitious matrix. In practice, however, most concrete structures are exposed to external sulfate attack at early age and initiation or incubation of sulfate attack more than its later consequences seem to be a recurrent topic of debate. In this work, paste samples prepared with either CEM I (Portland cement) or CEM III/A cement (blended cement with 62% slag) at a water to binder mass ratio of 0.60 are immersed in sodium sulfate solution (15 g/l Na2SO4) at controlled pH condition (pH = 8±1) after 24 hours. Sulfate ingress is measured using ICP-AES