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Advances in Civil Engineering
Volume 2010, Article ID 136768, 10 pages
http://dx.doi.org/10.1155/2010/136768
Research Article

Influence of Air Temperature on the Performance of Different Water-Reducing Admixtures with Respect to the Properties of Fresh and Hardened Mortar

1Universidade Federal de Santa Catarina, Campus Universitário, Eng.Civil, Bl. B/s.114, 88040970 Florianópolis, Brazil
2Instituto Federal de Santa Catarina, Avenida Mauro Ramos 950, 88020-300 Florianópolis, Brazil

Received 24 May 2010; Revised 4 September 2010; Accepted 11 October 2010

Academic Editor: K. Soudki

Copyright © 2010 Wilson Ricardo Leal Silva et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The performance of water-reducing admixtures used in concrete is affected by the weather conditions to which the concrete mixture is exposed. The most used WRAs are lignosulfonate, naphthalene, and polycarboxylate. However, they react differently to weather conditions, especially to air temperature. Therefore, it can be useful to evaluate how temperature affects admixture performance. In this study, the performance of three admixtures (naphthalene, lignosulfonate, and polycarboxylate) was evaluated at 15, 25, and 35°C by means of the flow table test, mixture air content, and compressive strength. Moreover, mixture temperature was monitored and time-temperature curves were plotted in order to assess whether the admixtures affected cement hydration reactions at different temperatures. The final results indicate that an increase in temperature leads to an increase in saturation dosage; lignosulfonate had the most pronounced retarding effect, followed by polycarboxylate, and finally, naphthalene, and considering the weather conditions in the area where the study was carried, the final finding would be that the naphthalene-based admixture had the best performance.