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Three-point bending tests on notched beams of a high-strength concrete have been conducted using both a servo-hydraulic machine and a self-designed drop-weight impact device. The work of fracture and the peak load were measured over a wide range of displacement rates (loading rates). Under low displacement rates, from 10-4 mm/s to 10 mm/s, the tests were performed with the servo-hydraulic machine; from 102 mm/s to 103 mm/s we used the drop-weight impact machine instead. The results show that the work of fracture and the peak load increase as the displacement velocity increases. Nevertheless, such trend is relatively mild under low rates and can be attributed to viscous effects mainly originated by the presence of water in the pore structure. Under high rates the increases in the work of fracture and in the peak load are dramatic due to the effect of inertia.