Nanoindentation Characterization of Calcium-Silicate-Hydrate with Different Curing Conditions

摘要

The calcium-silicate-hydrate(C-S-H) existing in cement-based materials has been focused on for a long time,however,the nanometer-scale properties are rarely concemed,because of its complicated structure. In this paper we study the nanomechanical properties of C-S-H by nanoindentation measurement,particular attention is paid to the pastes cured for 2 days and 28 days,respectively, both at 20℃ and 60℃. The results demonstrate in all cases the existence of two types of C-S-H with low stiffness and high stiffness. Also,the two types of C-S-H are of different characteristic modulus. The average modulus of each C-S-H is almost the same for all pastes tested,indicating that the heat curing process does not change the intrinsic mechanical properties of the C-S-H. However,the volumetric proportion of two types of CSH is changed at 60 ℃ compared to that at 20℃ at the early age.