EFFECT OF VIBRATIONS OF FRESH CONCRETE ON THE BEARING CAPACITY OF OVERLAPPING STRUTS

EINFLUSS VON ERSCHUETTERUNGEN VON FRISCHEM BETON AUF DIE TRAGFAEHIGKEIT VON UEBERGREIFUNGSSTOESSEN

THE STUDIES ARE INTENDED TO DETERMINE WHICH RELATIVE MOVEMENTS BETWEEN HARDENING CONCRETE AND REINFORCEMENT CAN BE ABSORBED WITHOUT DAMAGE TO THE BONDING PROPERTIES. IT IS INTENDED TO UNDERTAKE TENSILE TESTS ON OVERLAPPING STRUTS EMBEDDED IN A CONCRETE CASING. THE DIMENSIONS OF THE CASING ARE IN ACCORDANCE WITH THE OVERLAP LENGTHS SPECIFIED IN DIN 1045. TRANSVERSE MOVEMENT IS NOT EXPECTED: CONCRETE COVER IS ABOUT 5 CM ON EACH SIDE. RIBBED BARS WITH A DIAMETER OF 12 MM ARE BEING USED. THE VIBRATION ACTION IS TO BE INTRODUCED TRANSVERSELY ONTO THE EMBEDDED BARS. IT IS KNOWN FROM PREVIOUS TESTS THAT THE CRITICAL PHASE IS BETWEEN THE 2ND TO THE 6TH HOUR AFTER THE COMPACTION OR MIXING OF THE CONCRETE. IT IS THEREFORE INTENDED TO TEST SEVERAL SIMILAR SAMPLES AT VARIOUS TIMES WITHIN THIS CRITICAL PHASE BY INTRODUCING CERTAIN VIBRATIONS AND DETERMINING THEIR EFFECT ON THE DEVELOPMENT OF THE BOND. THE TENSILE TEST WILL FOLLOW AFTER 28 DAYS.