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Title: Evaluation of Structural Build-Up at Rest of Mortar and Concrete Using RRT Data

Author(s): Amziane

Publication: Web Session

Volume: ws_S22_Amziane.pdf


Appears on pages(s):



Date: 3/28/2022

This presentation shows the results of the static yield stress at rest of three mortar and five concrete mixtures that were determined using two ICAR rheometers, Viscomat XL and EbTV rheometers, and the plate test. For the measurements carried out with rheometers, three different structural build-up indices (i.e., structural build-up rate, critical time, and coupled effects of initial static yield stress and rate of structural build-up) were determined. The indices were established using two static yield stress values measured after 10 and 40 minutes of rest as well as three static yield stress values that combine the two static yield stress measurements and the initial dynamic yield stress obtained from the flow curves. The presentation discusses the test results and highlights inaccuracies that can be encountered in determining the static yield stress. Test results indicate that all the ICAR rheometers and selected thixotropic indices can provide similar results, and that the dispersion between the test results obtained from different rheometers can be considerably reduced when using three yield stress values to calculate the rate of the static yield stress at rest.