3D porosity distribution of partly calcium leached cement paste

Calcium leaching of cement-based materials is one of durability concerns in concrete structures. Calcium leaching leads to high porosity and porosity gradient near the wet surfaces of cement-based materials. In this research, the 3D porosity distributions of partly leached cement pastes with different water-to-cement ratios are characterized for the first time, and the porosity evolution caused by calcium leaching are discussed. The results are verified using the average porosities of the partly leached specimen. From the quantitative porosity results, large porosities over 60% are observed on the leached parts, and very sharp porosity gradients are observed on the leaching fronts. The results of current research can be used for the verification of calcium leaching models and for understanding the leaching mechanism. (C) 2013 Elsevier Ltd. All rights reserved.