In order to tackle behavior of individual components in concrete cells under shock loading, a multi-part model for concrete is presented, wherein mortar and aggregate are assumed to be in mechanical equilibrium and compressed or released isentropically. Computational simulations of plate shock experiments using the multi-part model for concrete are performed. Computational velocity histories of the free surface of the target are compared with experimental results. Nonlocal response of the multi-part model for concrete to uniform shock loading is presented. The irregular aggregate distribution in actual concrete is replaced by a distribution of single-sized equally separate aggregates and the radius of influence surrounding each aggregate is given. The phenomena accompanied by the passage of a spherical shock wave through the mortar and aggregate are discussed. It is shown that RayleighTaylor instability would cause separation of mortar and aggregate seriously for concrete with porous mortar at low initial density. It is shown that the behavior of the interface between mortar and aggregate under shock loading is captured qualitatively by the multi-part model for a simulated concrete cell. The multi-part model presented in this paper can be expected to numerically simulate shock loading behavior of concrete.