Describing the Failure Characteristics of Concrete Derived from Standard ASTM Testing-An Illustration of Full-Field Measurement Using 3D Digital Image Correlation

Concrete is one of the most recognized materials in civil infrastructure with a long history of applications, but its nonhomogeneous nature and complex multi-phase interactions across different dimensional scale levels have always presented a challenge for describing its behavior. In practice, it is assumed that the bulk material is approximately homogeneous while the behavior can be described using empirical models developed based on series of experimental tests. Over time, most of these experimental methods have been standardized, with most yielding a single-value parameter to define the overall response characteristic of the materials. However, the majority of these methods are not well suited to characterize local features, which often govern the failure characteristics of such brittle material. Recent advances in non-contact full-field measurement technologies, such as digital image correlation (DIC), have provided the opportunity to revisit this complex behavior and comprehensively characterize the behavior of concrete at specimen scale level. In this manuscript, 3D-DIC is used to evaluate the behavior of two conventional concrete mixes tested according to a series of ASTM standard tests. The experimental study consisted of a series of concrete tests including compression, modulus of elasticity, split tensile, and flexural tests. Results from this investigation demonstrated the suitability of the DIC technique for characterizing the full-field behavior of concrete subjected to various states of stresses and providing a mechanism to understand the linkage between local behavioral features and corresponding failure characteristics. Comparisons of experimental results to those obtained from theoretical predictions also highlighted the shortcomings associated with these existing theoretical approaches in describing the brittle nature of concrete. Results from this investigation provided a foundation for improving the current knowledge base regarding the behavioral features of conventional concrete materials and provides a framework for efficiently describing the behavior of the next generations of innovative high-performance cementitious composites.