# Thermal conductivity of porous jennite by molecular dynamics method

## TL;DR

This study uses molecular dynamics simulations to analyze how porosity and temperature affect the thermal conductivity of porous jennite, a key component in cement paste, revealing significant decreases with porosity and complex temperature dependence.

## Contribution

It provides a detailed molecular dynamics analysis of porous jennite's thermal conductivity, including porosity and temperature effects, using validated computational methods.

## Key findings

- Thermal conductivity decreases significantly with porosity.
- Temperature influences thermal conductivity, increasing then decreasing with temperature.
- The empirical coherent potential model accurately predicts conductivity changes.

## Abstract

The thermal conductivity of porous jennite, as the major component of cement paste, and its porosity and temperature dependences are simulated by molecular dynamics methods using ClayFF force field. The porous jennite models with different porosities are created by removing atoms within the sphere from bulk jennite model. The thermal conductivity elements of bulk jennite calculated by equilibrium Green-Kubo method are almost identical to those by non-equilibrium M\"{u}ller-Plathe (MP) method at 300 K. The volumetric thermal conductivity of porous jennite is found to decrease from 1.141 W/m$\cdot$K to 0.144 W/m$\cdot$K as increasing the porosity from 0\% to 72.22\% at 300 K, following the empirical coherent potential model when the pore is assumed to be filled with air. As increasing temperature, the thermal conductivity is observed to increase from 240 K to 560 K and gradually decrease until 1100 K for porous jennites with the porosities of 0\%, 15.99\% and 32.79\%.