Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.cemconres.2016.11.017
Title (Primary) The influence of substrate moisture preparation on bond strength of concrete overlays and the microstructure of the OTZ
Author Benshausen, H.; Höhlig, B.; Talotti, M.
Source Titel Cement and Concrete Research
Year 2017
Department TUCHEM
Volume 92
Page From 84
Page To 91
Language englisch
Keywords Concrete repair; Bond strength; Microstructure; Overlay transition zone; SEM
UFZ wide themes RU4;
Abstract The influence of substrate moisture preparation on the direct shear bond strength of composite substrate-overlay specimens was evaluated. The substrate surface was exposed to four different moisture conditions prior to overlay application. A quantitative analysis of backscattered electron images of the microstructure of the overlay transition zone was carried out to quantify its properties along the interface and help analyse the results of the shear bond testing. The results show that pre-wetting the substrate surface prior to application of the overlay provides no added benefit towards increasing the bond strength and may in some cases reduce bond strength significantly. The microstructural investigations confirmed that pre-saturated substrates increase the w/c ratio and the porosity in the overlay transition zone (OTZ), which was found to have a thickness of about 100 μm. The OTZ in overlays cast on dry substrate surfaces had lower porosity and an increased amount of anhydrous cement.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=19478
Benshausen, H., Höhlig, B., Talotti, M. (2017):
The influence of substrate moisture preparation on bond strength of concrete overlays and the microstructure of the OTZ
Cem. Concr. Res. 92 , 84 - 91 10.1016/j.cemconres.2016.11.017