A detailed investigation of the nature of the intruded fluid obtained by Rietveld analysis shows that water molecules penetrate first chabazite at the intrusion pressure of 54 and 60 MPa for 2 M NaCl and CaCl 2 respectively, followed by electrolyte intrusion at a much higher pressure of ∼250 and ∼600 MPa and the concentration inside the chabazite is found to be much higher than those of the bulk, closed to the saturation concentration. Once intruded, it is shown that electrolyte interpher with silanol defect, but it does not mean in absolute that silanol defects would results in itself on electrolyte intrusion at a higher concentration than the bulk. The non-intrusion of electrolyte is consistent with experiments reporting only penetration of water molecules at the intrusion pressure, but the reported intrusion of electrolyte at a much higher pressure may not be accessible due to limits of both forcefield and classical simulations. First, the force field used to model interactions within the zeolites are tailored to reproduce the intrusion of TIP4P water in silicalite-1 and may not be relevant to describe properly interaction with water at very high pressure. Second, the use of our current empirical force field to model electrolyte by a simple electrostatic potential coupled with Lennard-Jones interaction does not take into account polarizability, charge transfer or use of unreduced Coulomb interactions, that may relevant at higher pressure. 63