Title:
Internal Cracking and Strain Softening Response of Concrete Under Uniaxial Compression
Author(s):
S. P. Shah and R. Sankar
Publication:
Materials Journal
Volume:
84
Issue:
3
Appears on pages(s):
200-212
Keywords:
compression; concretes; cylinders; deformation; loads (forces); microcracking; microscopy; petrography; specimens; strains; strength; stress-strain relationships; Materials Research
DOI:
10.14359/1926
Date:
5/1/1987
Abstract:
Understanding the strain-softening response of concrete is important for numerical modeling of the constitutive behavior of concrete. The strain-softening response, and hence the internal cracking, depends on the method of testing and the specimen-machine boundary effects. In this study the nature and extent of internal cracking were studied for concrete cylinders subjected to axial strains in the post-peak part of the stress-strain curve. Several testing methods to reduce the end-restraint were evaluated and the one that gave essentially homogenous stress distribution was used for the study. Longitudinal and transverse slices of the specimens loaded to different values of axial strains were examined using petrographic techniques for microcracks. Internal cracking was uniformly distributed in the pre- and the postpeak regions. However, the cracking seemed to localize just before and immediately after the peak near the free edge of the cylinder. The direction of cracking was essentially along the compressive loading direction, and no shear bands were observed.