Studies of cementitious materials with molecular dynamics simulations

摘要

In this study we perform molecular dynamics (MD) simulation on several cementitious-related materials such as CSH C3S C3A as well as 11 and 14 °A tobermorite A magnesium-substituted tobermorite model is studied and can be stabilized Our molecular models are equilibrated and stabilized with empirical interatomic potentials through LAMMPS for stress-strain relationships In addition quantum molecular dynamics (QMD) simulation with SIESTA was performed on the minerals to verify their structures as well as thermal expansion coefficients and bulk modulus The Ewald method was adopted to calculate Coulomb electric potentials Atomic structural analysis such as radial distribution function (RDF) structure factor (SF) X-ray diffraction (XRD) of the materials are conducted Vibration spectra are calculated from velocity autocorrelation functions Mechanical properties of the materials are discussed from calculated quantities In the result of 14 °A tobermorite the shear modulus is around 15 8 GPa ~ 37 5 GPa thermal expansion coefficient is (10^6K^-1) and bulk modulus is 46 0 GPa in atmospheric In addition 14 °A tobermorite may undergo a phase change around 8 GPa at room temperature according to a change in bulk modulus and atomic configuration

獎項日期	2014 8月 29
原文	English
監督員	Yun-Che Wang (Supervisor)