Water Sensitivity of Cement-Based Materials

This book redefines concrete as a moisture-responsive, porous material, revealing how cement-based materials interact with water through their nanoscale pore structure. This transforms our understanding of dimensional stability, long-term durability, and other aspects of concrete science. Using low-field nuclear magnetic resonance relaxometry, the author non-destructively characterises the in-situ nanoscale pore structure of white cement-based materials and uncovers how it evolves with water content. The author identifies “water sensitivity”—the wetting expansion and drying contraction of calcium silicate hydrate—as the mechanism behind this behavior, analogous to clay minerals. The water sensitivity theory is validated by the microstructural characteristics of the dynamic pore structure, including a layered structure with a large specific surface area and a negative surface charge, and is substantiated by experimental results on permeability and sorptivity. Building on this framework, the book reexamines the effects of the water-to-cement ratio and curing temperature on the pore structure and water permeability of cement mortars. The book also successfully models phenomena, including deviated long-term water absorption, the anomalous dependence of sorptivity on initial saturation, and the isothermal drying of cement-based materials. This book will serve as an essential reference for concrete scientists, materials engineers, and researchers studying the dimensional stability and long-term durability of cement-based materials, as well as their many other moisture-regulated performances.