Abstract: Flowing and filling process of self-compacting concrete (SCC) in the complex voids of rockfill is of high concealability, so it is difficult to scientifically quantify the filling effect of rock-filled concrete (RFC). This study conducts an in-situ monitoring and experiment on SCC at Shibahe gravity dam: lay temperature sensors at different locations of a typical section; measure real-time fresh concrete levels; track pouring locations; record the instants of monitoring sensors covered by fresh concrete mixture. And the free surface profiles of fresh SCC are plotted for different instants. The test results show SCC has a great lateral self-flow filling capacity－it can flow and reach the monitoring section 17 m away from the pouring location. In pouring and filling of the fresh SCC, its surface levels upstream and downstream of the section keep a trend of rising at nearly constant speeds. The slope I_s of the free surface is about 0.03 - 0.08 upstream and downstream of the section and roughly 0.06 along the dam axis in the whole impermeable layer. The damping coefficient η of the rockfill voids is about 65 - 173 in theoretical calculations. Analysis of the temperature data of rockfill-SCC mixture reveals that during pouring, its spatial distribution starts from heterogeneous but approaches relatively uniform soon after mixing. The process of flow filling and temperature rise in the mixture observed in-situ synchronously is of great significance for further quantitative evaluation of RFC compactness and mesoscopic temperature distribution.

Key words: rock-filled concrete, in-situ experiment, flowing and filling effect, free surface, temperature monitoring