Naqi Ali, Delsaute Brice, Königsberger Markus, Staquet Stéphanie
BATir Department, Université Libre de Bruxelles, CP194/02, 50 Avenue F.D. Roosevelt, 1050 Brussels, Belgium.
Institute for Mechanics of Materials and Structures, TU Wien, Karlsplatz 13/202, 1040 Vienna, Austria.
Materials (Basel). 2022 Dec 30;16(1):373. doi: 10.3390/ma16010373.
The growing use of blends of low- and high-calcium solid precursors in combination with different alkaline activators requires simple, efficient, and accurate experimental means to characterize their behavior, particularly during the liquid-to-solid transition (setting) at early material ages. This research investigates slag-fly ash systems mixed at different solution-to-binder (s/b) ratios with sodium silicate/sodium hydroxide-based activator solutions of varying concentrations. Therefore, continuous non-destructive tests-namely ultrasonic pulse velocity (UPV) measurements and isothermal calorimetry tests-are combined with classical slump flow, Vicat, and uniaxial compressive strength tests. The experimental results highlight that high alkali and silica contents and a low s/b ratio benefit the early-age hydration, lead to a faster setting, and improve the early-age strength. The loss of workability, determined from the time when the slump flow becomes negligible, correlates well with ultrasonic P-wave velocity evolutions. This is, however, not the case for Vicat or calorimetry tests.
越来越多地使用低钙和高钙固体前驱体与不同碱性激发剂的混合物，这就需要简单、高效且准确的实验方法来表征它们的行为，尤其是在材料早期龄期的液 - 固转变（凝结）过程中。本研究考察了以不同的固液比（s/b）与不同浓度的硅酸钠/氢氧化钠基激发剂溶液混合的矿渣 - 粉煤灰体系。因此，将连续无损测试——即超声脉冲速度（UPV）测量和等温量热测试——与经典的坍落度流动、维卡和单轴抗压强度测试相结合。实验结果表明，高碱和二氧化硅含量以及低固液比有利于早期水化，导致更快的凝结，并提高早期强度。由坍落度流动变得可忽略不计的时间所确定的工作性损失，与超声纵波速度的变化有很好的相关性。然而，维卡或量热测试并非如此。
