Nanoscale insight into structural characteristics and dynamic properties of C-S-H after decalcification by reactive molecular dynamics simulations

The mechanical properties of cement will deteriorate after decalcification but will increase with the increasing strain rate. However, the mechanisms are not evident. Therefore, the variants of structure and mechanical characteristics caused by decalcification for calcium silicate hydrate (C-S-H), the major binder phase of cement, were evaluated utilizing reactive molecular dynamics simulations(MD) at the nanoscale. The results indicate that decalcification only significantly weakens the dynamic properties of C-S-H along the interlayer direction, which is supported by microscopic experimental findings. The strain rate sensitivity is positively correlated with the level of decalcification of C-S-H. The mechanisms are discovered by changes in structural features and chemical bonds. The findings shed light on the structure-dynamic properties relationship of C-S-H after decalcification at the nanoscale.