Liu, H.; Dong, S.; Tang, L.; Anoop Krishnan, N. M.; Masoero, E.; Sant, G.; Bauchy, M.
Journal of Colloid and Interface Science 2019, 542, 339–346
Publication year: 2019

When subjected to a sustained load, jammed colloidal gels can feature some delayed viscoplastic creep deformations. However, due to the long timescale of creep (up to several years), its modeling and, thereby, prediction has remained challenging. Here, based on mesoscale simulations of calcium–silicate–hydrate gels (CASAH, the binding phase of concrete), we present an accelerated simulation method—based on stress perturbations and overaging—to model creep deformations in CASAH. Our simulations yield a very good agreement with nanoindentation creep tests, which suggests that concrete creep occurs through the reorganization of CASAH grains at the mesoscale. We show that the creep of CASAH exhibits a logarithmic dependence on time—in agreement with the free-volume theory of granular physics. Further, we demonstrate the existence of a linear regime, i.e., wherein creep linearly depends on the applied load—which establishes the creep modulus as a material constant. These results could offer a new physics-based basis for nanoengineering colloidal gels featuring minimal creep.