Ambient drying of partially water-penetrated concrete: chemical phase and pore structure changes and drying behaviour under hyperspectral imaging observation

A comprehensive understanding of microstructural evolution and moisture distribution under ambient drying conditions is essential for evaluating structural performance. This study examines the drying behaviour and microstructural changes in partially water-penetrated concrete under ambient drying conditions. Concrete specimens with varying water-to-cement ratios and curing conditions were prepared, subjected to partial water penetration, and subsequently exposed to ambient drying. Hyperspectral imaging (HSI) was employed to visualise moisture profiles during drying, complemented by X-ray diffraction and mercury intrusion porosimetry to analyse microstructural changes before and after exposure. The results demonstrate the successful application of HSI for visualising moisture distribution in concrete during drying. Porosity reduction was observed post-drying, with the region further from the drying surface exhibiting a significant change. These findings offer valuable insights into the drying behaviour and microstructural evolution of partially water-penetrated concrete, contributing to the assessment of its durability performance.