A Experimental Study Of Dynamical Properties Of Two New Concrete Materials

Self-compacting concrete (ab. SCC) and Macro-defect-free (ab. MDF) cements have become two important orientation of high performance concrete materials, and study of dynamical properties of the two concrete materials become more important.In this paper, MDF cements and SCC with different strength (such as c45, c55 and c65) have been studied on their material dynamical performance and constitutive relation, etc.(1) Dynamic compressive stress-strain curves of the MDF cements and SCC are obtained at different strain rates from 10s^-1 to 1000 s^-1 by SHPB tests. A pulse shaping technique has been used in the split Hopkinson bar (SHPB) experiments, for ensuring the specimen in dynamic stress equilibrium and loaded under constant strain rate during the test.(2) Dynamical properties of the two concrete materials have been analysed based on the compressive stress-strain curves at different strain rates, which show that the two concrete materials are sensitive to the strain-rates, and the higher the strength of the SCC, the more sensitive the material properties to the strain rate.(3) The experimental results also showed that the higher the strength of SCC, the higher the failure strain of SCC. The failure strain of SCC is about 7‰⁹‰, which is far higher than that of general virbro-casting concrete.(4) According to the experimental results of the two concrete materials under different strain rates, the constitutive relations have been established for the compression behavior of the two concrete materials.The jobs of this dissertation reveal some characteristics of dynamic mechanical behaviors of the two concrete materials. All the experimental results and analysis in this paper provide a good exploration for further researches and applications of the mechanical behavior of the SCC and MDF cements.