Steel fibre reinforced self-compacting concrete subjected to quasi-static and dynamic loading conditions

The paper deals with the self-compacting concrete reinforced with short steel fibres. The dosage of the fibres was equal to 118 kg/m³. The SFR-SCC specimens were subjected to the high strain rates and the accompanying quasi- static compression and flexural tensile tests. The fibers improved the post-peak response of SCC to the quasi-static conditions, however not significantly. The high strain rate tests were performed with a use of the SHPB stand consisted of the bars with a diameter of 40 mm. The special attention was paid to the procedure of conducting the SHPB tests. The assumptions that must be fulfilled during the tests were discussed and summarized. The conditions were: the equilibrium stress state in the specimen, the application of proper pulse shaper and ensuring full surfaces fitting of the specimen to the bars. The stress-strain curves obtained in the tests were characterized by the very good repeatability what confirms the need of fulfillment of the above mentioned requirements. Generally, the pronounced increase of the compressive strength under high strain rates was noted. The average Dynamic Increase Factor was equal to 2.18, what indicates that the SFR-SCC is a highly strain rate sensitive material.