Effects of Zn substitution on the mechanical and thermal transport properties of calcium silicate hydrate: a...

Calcium silicate hydrate (C-S-H) was selected as the model system in this study. Pristine C-S-H and Zn-substituted C-S-H models, in which Zn replaced Si at either Q¹ or Q² sites, were constructed to investigate structural stability, tensile behavior, and thermal conductivity. The results show that Zn doping reduces the stability of the system. Q¹ doping formed a more stable local coordination region, whereas Q² disrupted silicate-chain continuity. Zn doping weakens the mechanical properties of C-S-H, with more pronounced reductions in the Y and Z directions. Zn doping lowers thermal conductivity in all directions, with Q¹ affecting Z-direction interlayer transfer and Q² affecting Y-direction chain transfer.

Molecular dynamics simulations (MD) were performed to study Zn-doped C-S-H. After energy minimization and NPT/NVT equilibration, structural characteristics were analyzed. Uniaxial tensile and non-equilibrium heat transfer simulations were then conducted to evaluate mechanical properties and thermal conductivity.