THE INFLUENCE OF SLENDERNESS ON THE DIRECT TENSILE STRENTH OF CONCRETE CYLINDERS AND PRISMS /IN FRENCH/

EXPERIMENTAL STUDIES HAVE SHOWN THE RELATION BETWEEN THE SLENDERNESS OF TEST SPECIMENS - VERTICALLY AND HORIZONTALLY COMPACTED CONCRETE CYLINDERS AND PRISMS - AND THE DIRECT TENSILE STRENGTH OF CONCRETE. NEW TESTING EQUIPMENT WITH NEW TYPES OF GLUE, DESIGNED BY THE PRAGUE TECHNICAL UNIVERSITY INSTITUTE OF BUILDING RESEARCH WAS USED TO DETERMINE THIS STRENGTH. ALTHOUGH TESTS WERE CARRIED OUT WITH TWO DIFFERENT GRADINGS (RIVER PEBBLES AND GRANULAR AGGREGATES) NO BASIC DIFFERENCE IN THE PERCENTAGE INCREASE OF THE DIRECT TENSILE STRENGTH WAS ESTABLISHED AS A FUNCTION OF THE SLENDERNESS OF THE TEST SPECIMENS. THE DIRECT TENSILE STRENGTH OF CONCRETE IS NOT INFLUENCED BY THE GLUEING OF TEST SAMPLES IF THE SLENDERNESS RATIO OF THE CYLINDERS REACHES 2 AND THAT THE HEIGHT TO AREA RATIO OF THE PRISMS EQUALS 3. ACCORDING TO COMMONLY ACCEPTED CURVES OF PERCENTAGE INCREASE IN APPARENT DIRECT TENSILE STRENGTH OF TEST SAMPLES IN WHICH SLENDERNESS COEFFICIENT IS SMALLER THAN ACCEPTED BASIC COEFFICIENT, IT'S POSSIBLE TO DETERMINE REAL DIRECT TENSILE STRENGTH OF THE CONCRETE STUDIED. /LCPC/A/RRL/