Nanoindentation-probed Oliver-Pharr half-spaces in alkali-activated slag-fly ash pastes: Multimethod identification of microelasticity and hardness. Issue 26 (26th October 2022)

• Record Type: Journal Article
• Authors: Königsberger, Markus; Zelaya-Lainez, Luis; Lahayne, Olaf; Pichler, Bernhard L. A.; Hellmich, Christian
• Is Part Of: Mechanics of advanced materials and structures. Volume 29:Issue 26(2022)
• Page Start: 4878
• Page End: 4889
• Publication Date: 2022-10-26
• Subjects: Alkali-activated materials -- microscopy -- image analysis -- ultrasonic testing -- micromechanics -- nanoindentation; Composite materials -- Mechanical properties -- Periodicals; Composite construction -- Periodicals; 620.118
• DOI: 10.1080/15376494.2021.1941450
• Languages: English
• ISSNs: 1537-6494

Abstract

Abstract: The mechanical interactions of C-(N-)A-S-H (Calcium-sodium-aluminum-silicate-hydrate) gel with slag and fly ash inclusions in alkali-activated materials (AAM) are quantified through image-supported grid nanoindentation. Nonuniform distributions of indent-specific indentation properties reveal that the elasticity-related domain is up to 130 times the contact indentation depth, while the hardness-related domain, in turn, is by a factor of two to three smaller. These rather large domains are consistent with the slag/fly-ash inclusions being much stiffer and harder than the surrounding C-(N-)A-S-H gel. Corresponding Hashin-Shtirkman bounds for the overall AAM stiffness consistently frame ultrasonic data characterizing this homogenized material scale. This confirms our new testing protocol.