High-Strength Concrete Subjected to Triaxial Compression

Abstract

The behavior of high-strength concrete subjected to multiaxial states of stress was studied. An experimental program was undertaken to quantitatively determine the failure surface for high-strength concrete. Results from this study provide the means to predict the failure condition for high-strength concrete under combined stresses. The experimental program was comprised of testing high-strength concretes at three different compressive strength levels. The three strength levels included concretes with compressive strengths of 6 ksi (42 MPa), 10 ksi (69 MPa), and 15 ksi (103 MPa). The triaxial tests were performed on 4-by-8 in (100-by-200 mm) cylindrical specimens. The confining pressures employed in the experiments ranged from 1,200 psi (8.3 MPa) to 12,000 psi (82 MPa). A series of uniaxial tension and compression tests were also performed to develop the necessary data for establishment of the failure criterion. Empirical relationships were developed for prediction of axial strength as a function of confining pressure. In general, the axial strength of high-strength concrete increases with increased confining pressure. However, in comparison with the normal-strength concrete, the effect of confining pressure on the failure strength of high-strength concrete is less pronounced.