Rock-filled concrete technology has been used in the construction of 175 dams bythe end of June, 2024. Due to the requirement of a particle size of no less than 300mm for rock-fills, it poses a challenge for testing the mechanical properties of rock-filled concrete. In this study, specific molds are designed and manufactured, and cubic specimens of self-compacting concrete (SCC) and rock- filled concrete (RFC) with 900mm side length are made. By using a testing machine with maximum compressive load of 30000kN, laboratory tests on the compressive and splitting-tensile strengths of large-scaled RFC are carried out. The results show that the molds used are reliable. Both large-scaled SCC and RFC show ‘X’-shaped failure pattern in compression test, which is in consistent with normal concrete. For the specimen of 900mm side length, the compressive and spitting-tensile strengths of RFC is 12.6% and 13.2% larger than SCC respectively. Compared to the SCC specimen of 150mm side length, the compressive strengths of RFC and SCC decreased 24% and 33% respectively, while the splitting-tensile strengths of RFC and SCC decreased 33% and 42% respectively, which shows strong size effect on the mechanical properties of RFC and SCC. There are three types of failure in RFC specimen for both compressive and splitting-tensile tests, rock-fills’ breakage, SCC failure and failure on the interface between rock-fills and SCC. This research provides valuable test data for engineering scale RFC, which can be a reference for the future design and construction of RFC dams.
