Micro- and nanostructural investigations of high and ultra-high performance concrete under fatigue

Engelhardt, Michael; Kalytta-Mewes, Andreas; Volkmer, Dirk; Lohmann, Jessica; Ritter, Martin; Schaan, Gunnar; Schmidt-Döhl, Frank; Ali, Mohamed Abubakar; Basaldella, Marco; Haist, Michael; Kern, Bianca; Lohaus, Ludger; Oneschkow, Nadja; Rozanski, Corinna; Timmermann, Tim; Grosse, Christian; Birtel, Veit; Garrecht, Harald; Madadi, Hamid; Markert, Martin

doi:https://doi.org/10.15480/882.15220

Micro- and nanostructural investigations of high and ultra-high performance concrete under fatigue

Citation Link: https://doi.org/10.15480/882.15220

Basic Data Publication

Publikationstyp

Journal Article

Date Issued

2025-04-30

Sprache

English

TORE-DOI

10.15480/882.15220

TORE-URI

https://hdl.handle.net/11420/55726

Publisher Version

Journal

International journal of fatigue

Volume

199

Article Number

109038

Citation

International Journal of Fatigue 199: 109038 (2025)

Publisher DOI

10.1016/j.ijfatigue.2025.109038

Scopus ID

2-s2.0-105004743286

Publisher

Elsevier

Abstract

A fine-grained UHPC, both undamaged and damaged by fatigue loading, was comparatively examined by various microstructural analytical methods, to evaluate the different techniques with respect to their applicability and relevance for the investigation of fatigue damage processes. The fatigue tests were stopped at the transition from phase II to phase III of the s-shaped strain development. The cyclic compression loading was performed with a frequency of ft = 1 Hz, and a stress level between Smin = 0.05 and Smax = 0.75 (fcm = 170.2 MPa). The fatigue process under these loading conditions is dominated by alterations and damages on the nano-scale, that can be observed by transmission electron microscopy. The resulting coarsening of the pore structure was also visible with dynamic vapor sorption. Nanoindentation indicates, that changes of the HD-C-S-H-phase occur. IR spectroscopy also indicates changes of the C-S-H phase and thermal analysis changes of the water content. Dynamic mechanical analysis (DMA) gave insight into the complex Young's modulus and Poisson's ratio changes. The acoustic emission technique gives information on the different processes during the single phases of fatigue and reveal a very different damage behaviour of dry and moist materials. Some microcracks are visible with light microscopy. It appears, that the number of cracks after fatigue is higher than before. With X-ray computed tomography, X-ray powder diffraction, the drying behaviour, the free water uptake, the water uptake under vacuum and by mercury intrusion porosimetry no significant differences between specimens with and without fatigue loading could be observed in this examination.

Content

Subjects

Fatigue | HPC | Microstructure | Testing Methods | UHPC

DDC Class

620.1: Engineering Mechanics and Materials Science

541.3: Physical Chemistry

Funding References

Funding(s)

Projekt DEAL

Files

Lizenz

https://creativecommons.org/licenses/by/4.0/

Publication version

publishedVersion

Download

Name

1-s2.0-S014211232500235X-main.pdf

Type

Main Article

Size

21.58 MB

Format

Adobe PDF