Creep Mechanisms of Calcium–Silicate–Hydrate: An Overview of Recent Advances and Challenges

A critical review on existing creep theories in calcium–silicate–hydrate (C–S–H) is presented with an emphasis on several fundamental questions (e.g. the roles of water, relative humidity, temperature, atomic ordering of C–S–H). A consensus on the rearrangement of nanostructures of C–S–H as a main consequence of creep, has almost been achieved. However, main disagreement still exists on two basic aspects regarding creep mechanisms: (1) at which site the creep occurs, like at interlayer, intergranular, or regions where C–S–H has a relatively higher solubility; (2) how the structural rearrangement evolutes, like in a manner of interlayer sliding, intra-transfer of water at various scales, recrystallization of gelled-like particles, or dissolution–diffusion–reprecipitation at inter-particle boundary. The further understanding of creep behavior of C–S–H relies heavily on the appropriate characterization of its nanostructure.