42. Residual Structural Capacity of a High-Performance Concrete

In this study, the residual unconfined compressive strength of a high-performance concrete (f’c ∼ 140 MPa) was investigated using samples that were pre-loaded to specific states of triaxial confinement. The residual unconfined compressive strengths of the samples were then compared to the unconfined compressive strength of pristine samples not subjected to the pre-load triaxial conditions. To accomplish the pre-load triaxial conditions, the samples were first subjected to specified stress-strain paths corresponding to pure hydrostatic compression and uniaxial strain in compression. Both the hydrostatic compression and uniaxial strain (in compression) tests were performed at low- and high-pressure levels under controlled conditions to prevent reaching the material failure limit. Once the samples were tested through either hydrostatic compression or uniaxial strain, they were recovered and subjected to unconfined compression until failure. Data from these samples were compared to the unconfined compressive strength of pristine samples from the same concrete batch. Residual structural capacity was determined through a comparison of these values and as a means to quantify damage induced (both with and without shear) by the specified stress-strain paths. Applications of these data are discussed for future improvements to concrete constitutive models commonly used at the U.S. Army Engineer Research and Development Center to simulate dynamic events.