STUDY OF THE INFLUENCE OF THE SCALE EFFECT ON CONCRETE CREEP

ETUDE DE L'INFLUENCE DE L'EFFET D'ECHELLE SUR LE FLUAGE DU BETON

THE FIRST MEASUREMENTS MADE ON SMALL CROSS-SECTION BEAMS DURING PREVIOUS TESTS LEAD TO THE ASSUMPTION THAT THE LAW GOVERNING CONCRETE BEHAVIOUR UNDER LONG-TERM LOADING DEPENDS ON THE TRANSVERSE DIMENSIONS OF THE TEST UNITS, BUT THAT THE VARIATION IN CREEP AS A FUNCTION OF THESE DIMENSIONS IS NOT ADEQUATELY REPRESENTED BY THE CHARTS INCLUDED IN THE REGULATIONS. IT IS PROPOSED TO TAKE MEASUREMENTS OF CREEP DEFORMATIONS ON TEST PIECES OF DIFFERENT DIMENSIONS, BUT FAIRLY SIMILAR IN SIZE TO UNITS USED IN ENGINEERING STRUCTURES, WITH A VIEW TO STUDYING THE SCALE EFFECT. THIS WILL PERMIT TO PUT TO GOOD USE THE MEASUREMENTS ALREADY CARRIED OUT ON SMALL TEST PIECES BY USING A METHOD OF TRANSPOSING THE CREEP VALUES OBTAINED TO TEST SPECIMENS OF LARGER DIMENSIONS. MEASUREMENTS WILL BE MADE AT THE FOLLOWING INTERVALS: 1 DAY, TWO DAYS, THREE DAYS, TWO WEEKS, ONE MONTH, THEN EVERY OTHER MONTH UP TO THE TIME OF CREEP STABILIZATION.