STRUCTURAL LIGHTWEIGHT CONCRETE UNDER BIAXIAL COMPRESSION

AN EXPERIMENTAL STUDY WAS CARRIED OUT ON STRUCTURAL LIGHTWEIGHT CONCRETE UNDER SHORT-TERM BIAXIAL COMPRESSION. STRENGTH, DEFORMATIONAL BEHAVIOR AND FRACTURE UNDER VARIOUS COMPRESSIVE STRESS COMBINATIONS WERE STUDIED. STRESS-STRAIN RELATIONSHIPS ARE REPORTED FOR UNIAXIAL AND BIAXIAL COMPRESSION. FAILURE STRESS ENVELOPES WERE COMPARED WITH RESULTS FOR NORMAL CONCRETE, OBTAINED BY VARIOUS AUTHORS, AND WITH RESULTS FOR LIGHTWEIGHT CONCRETE OBTAINED BY ONE OTHER AUTHOR. THE MODES OF FAILURE OF SPECIMENS INDICATED THAT TENSILE DEFORMATION IS DOMINANT IN THE FAILURE MECHANISM OF STRUCTURAL LIGHTWEIGHT CONCRETE LOADED IN BOTH UNIAXIAL AND BIAXIAL COMPRESSION. THE APPLICATION OF TRANSVERSE COMPRESSION ON THE SPECIMENS CAUSED A STRENGTH INCREASE (24 TO 28 PERCENT) COMPARED TO UNIAXIAL COMPRESSIVE STRENGTH. THIS STRENGTH INCREASE IS DEPENDENT ON THE STRESS COMBINATION (MAXIMUM AT APPROXIMATELY SIGMA SUB 2/SIGMA SUB 1 EQUALS 0.4 TO 0.5), BUT NOT VERY MUCH ON COMPOSITION OF THE CONCRETE. /AUTHOR/