Abstract: Filling effect of self-compacting concrete (SCC) in rockfill gaps is a crucial factor of rock-filled concrete (RFC) strength and engineeing safety. The flow of fresh SCC in rockfill gaps can be regarded as a particle-Bingham fluid two-phase flow that is particularly complicated due to its non-Newtonian rheological characteristics and the complexity of its passage. In this work, SCC flows in the pores of rockfill material was studied by coupling the lattice Boltzmann method and particle discrete element method. We found out that these flows can fall into three regimes: dilute flow, dense flow and jamming. Aperture ratio, or the ratio of pore outlet size to particle diameter, is the most important factor of the flow and its jamming effect. It is much easier for SCC to form dense flow or jamming flow if its volume fraction of particles is higher. For dense flows, a relationship of outlet flow rate versus aperture ratio was established, which could be used to improve fresh concrete pouring technique.