Dental Prosthetics and Materials Science, Leipzig University, 04275 Leipzig, Germany.
Else Kooi Lab., Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, 2628 CT Delft, The Netherlands.
Molecules. 2020 May 19;25(10):2359. doi: 10.3390/molecules25102359.
This paper investigates the development of the alkalinity and its impact on carbon steel reinforcement embedded in alkali-activated fly ashes (AAFA) and alkali-activated fly ashes with ten percentage mass (wt%) of blast furnace slag (AAFAS)-based materials (geopolymer-GP). The pH analysis of eluates indicates a remarkable decrease of alkalinity in AAFA and AAFAS in the first hours of the geopolymerization process. Phenolphthalein solution and pore solution tests on concretes also show a sharp decrease of alkalinity with increased content in the binder due to carbonation. Micro X-ray computer tomography (µXCT) and electrochemical techniques indicate that the changed pH in the GP systems was accompanied by a decrease in the corrosion rates of steel reinforcement when compared to ordinary Portland cement (OPC) systems. In contrast to calcite and vaterite, which were detected in OPC and AAFAS after a carbonation process, only sodium carbonate natron was determined at lower levels in AAFA by X-ray diffraction (XRD).
本文研究了碱度的发展及其对碱激发粉煤灰（AAFA）和掺有 10%质量百分比高炉矿渣（AAFAS）的碱激发粉煤灰基材料（地质聚合物-GP）中嵌入的碳钢钢筋的影响。浸出液的 pH 值分析表明，在地质聚合过程的最初几个小时内，AAFA 和 AAFAS 的碱度显著降低。混凝土中的酚酞溶液和孔溶液测试也表明，由于碳化作用，粘结剂中的含量增加，碱度急剧下降。微 X 射线计算机断层扫描（µXCT）和电化学技术表明，与普通波特兰水泥（OPC）系统相比，GP 系统中 pH 值的变化伴随着钢筋腐蚀速率的降低。与 OPC 和 AAFAS 碳化后检测到的方解石和文石不同，XRD 仅在 AAFA 中较低水平检测到碳酸钠苏打。
