Carbonation and leaching of concrete are considered as the main degradation processes for many important applications (e.g. nuclear waste facilities, hydro structures) because of its importance for long-term durability assessment even with extremely slow processes. The degradation modifies the microstructure of cement-based materials from nano-scale up to microand meso-scale. However, there is no unique technique able to characterize these microstructural changes at the different scales. In this study, we introduced a combined method in which N2-adsorption, mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) were used to quantify the microstructural changes at nano, sub-micro, and micro level, respectively. With this approach, we obtain a larger range of pore size distribution and minimize the limitations of each technique. The characterizations were performed on sound, leached and carbonated cement pastes with different w/p ratios and limestone filler replacements. The leached and carbonated materials were obtained under accelerated conditions using ammonium nitrate solution and elevated pressure of pure CO2, respectively.
|14th International Conference on Durability of Building Materials and Components
|2017-05-29 → 2017-05-31