This paper describes an interaction phenomenon when a moving shock wave hits a two-phase medium of gas and particles. A carbon particle-laden oxygen gas is considered to be located along a ramp so that numerical integration is accomplished from the tip of ramp for a finite period. Transient development of thermo-fluid mechanical characteristics is calculated and discussed by changing the initial pre-shock gas temperature and pressure, incident shock Mach number, and particle size and mass fraction. For the numerical solution, a fully conservative unsteady implicit 2$^{nd}$ order time accurate sub-iteration method and a 2$^{nd}$ order Total Variation Diminishing (TVD) scheme are used with the finite volume method (FVM) for gas phase. For particle phase, the Monotonic Upstream Schemes for Conservation Laws (MUSCL) as well as the solution of the Riemann problem for the particle motion equations is used. In the results, depending on the conditions given, the shock-wave diffraction and the thermo-fluid mechanical behavior become remarkably different during relaxation period due to momentum drag, heat exchange and chemical reaction. In general, when more particles are present, it is found that the shock wave speed is reduced and the gas density becomes locally denser and locally more dilute. Especially, when a chemical reaction is active, there can be zones where the particle velocity is faster than the gas velocity.
