STUDIES OF THE BIAXIAL STRENGTH OF CONCRETE

UNTERSUCHUNGEN UEBER DIE ZWEIACHSIGE FESTIGKEIT DES BETONS

A NEW LOADING DEVICE WAS DEVELOPED WITH WHICH UNIFORM BIAXIAL COMPRESSION, COMPRESSION-TENSION AND TENSION-STRESSES CAN BE PRODUCED. THE TEST PIECES OF DIMENSIONS 20 X 20 X 5 CM WERE LOADED BY SO-CALLED STEEL BRUSHES WHICH CONSIST OF MANY INDIVIDUAL SMALL STEEL RODS COMBINED TO FORM A SET. USING THESE BRUSHES, BOTH COMPRESSION AND TENSILE FORCES CAN BE INTRODUCED ALMOST UNIFORMLY AND AT RIGHT ANGLES TO THE LOADING SURFACES OF THE PARALLELOPIPED-SHAPED CONCRETE TEST PIECE. A TWO-PART LOADING FRAME WAS CONSTRUCTED FOR APPLYING THE LOADS IN 2 DIRECTIONS. A SIMPLE HYDRAULIC SYSTEM ENABLES THE MAINTAINING OF A CONSTANT STRESS CONDITION DURING THE WHOLE TEST. USING THESE TEST DEVICES, CONCRETE SLABS 20 X 20 X 5 CM WITH VARIOUS PRISM STRENGTHS WERE TESTED UNDER DIFFERENT PRINCIPAL STRESS CONDITIONS.