Lecture by Prof. Eric N. Landis

'Measurements of Fiber and Load-rate Effects on Micro- and Macro-fracture of Ultra-High- Performance Concrete' is the title of the lecture given by Prof. Eric N. Landis (University of Maine, USA) on Friday, 14 August 2026.

Abstract:
Advances in 3D imaging have opened up different ways to observe the internal mechanisms that dictate how a material dissipates energy under extreme loading conditions. Specifically, quantitative analysis of such 3D images allow us to measure fracture and damage in new ways. In the study presented here, several new analysis techniques were applied to an ultra-high-performance concrete subjected to different loading rates. The cylindrical specimens were subjected to x-ray CT scans to create 3D images of the material‘s internal structure. Using a combination of digital volume correlation and discrete crack measurements we were able to break total damage down in macro-cracking and micro-cracking. Here the micro-cracking is defined as that due to the residual strain measured through DIC that is not visible as a macro-crack. While this definition is somewhat arbitrary and dependent on the resolution of the images, it allows us to quantify the effects of both loading rate and micro-structure on the distribution of cracking and damage in the material. Such quantitative information can be used to tune and validate computational models for these materials.

Lecture_Prof_Landis_14-08-2026.pdf