FURTHER INVESTIGATION ON THE REAL RATE EFFECT OF DYNAMIC TENSILE STRENGTH FOR CONCRETE-LIKE MATERIALS

Abstract

AFFECTED BY THE INERTIA EFFECT, REAL RATE EFFECT AND END FRICTION EFFECT (ONLY EXISTED IN SPLITTING AND SPALLING TESTS), THE EXPERIMENTAL TENSILE STRENGTH OF CONCRETE-LIKE MATERIALS GREATLY INCREASES WITH THE LOADING-RATE OR STRAIN-RATE. TO FURTHER INVESTIGATE THE INFLUENCE DEGREE OF REAL RATE EFFECT FOR CONCRETE-LIKE MATERIALS IN DYNAMIC TENSILE TESTS, THIS PAPER SYSTEMATICALLY CONDUCTS EXPERIMENTAL RESEARCH TO STUDY DYNAMIC BEHAVIORS OF CONCRETE-LIKE MATERIALS IN TENSILE EXPERIMENTS, VIZ. DIRECT TENSILE TESTS, SPLITTING TESTS AND SPALLING TESTS. AT THE SAME TIME, FINITE ELEMENT SIMULATIONS ARE EMPLOYED TO ANALYZE THE MECHANICAL CHARACTERISTICS OF CONCRETE-LIKE MATERIALS, WHERE A HYDROSTATIC PRESSURE DEPENDENT MODEL, THE DRUCKER-PRAGER CONSTITUTIVE MODEL, IS USED FOR SPECIMENS, WHICH CAN CONSIDER THE INFLUENCE OF INERTIA EFFECT. IN THE NUMERICAL MODEL, THE SPECIMEN IS SET WITH RATE-INDEPENDENCY, THUS THE PREDICTED DYNAMIC TENSILE STRENGTH OF SPECIMENS IS FREE OF THE REAL RATE EFFECT. THE END FRICTION EFFECT IS ALSO TAKEN INTO ACCOUNT IN THE NUMERICAL ANALYSIS OF DYNAMIC SPLITTING AND SPALLING TESTS. IT IS FOUND THAT THE DYNAMIC TENSILE STRENGTH ENHANCEMENT OF CONCRETE-LIKE MATERIALS IN NUMERICAL SIMULATIONS DOES NOT VARY OBVIOUSLY WITH LOADING-RATES, WHICH INDICATES THAT THE INERTIA EFFECT AND END FRICTION EFFECT MAKE LITTLE CONTRIBUTIONS TO THE DYNAMIC INCREASE FACTOR (DIF) OF CONCRETE-LIKE MATERIALS. THEREFORE, THE REAL RATE EFFECT DOMINATES THE DYNAMIC TENSILE STRENGTH ENHANCEMENT OF CONCRETE-LIKE MATERIALS IN LABORATORY TESTS, BUT THE INERTIA EFFECT AND END FRICTION EFFECT DO NOT.