Torres Ortega Ramon, Luna Velasco María, Arrieta Baldovino Jair
Civil Engineering Program, University of Cartagena, Calle 30 # 48-152, Cartagena de Indias 130001, Colombia.
Faculty of Engineering, University of Cartagena, Calle 30 # 48-152, Cartagena de Indias 130001, Colombia.
Materials (Basel). 2025 Mar 12;18(6):1248. doi: 10.3390/ma18061248.
Oil palm kernel shell ash (POFA), a byproduct of the highly cultivated agro-industrial sector in Colombia, has been widely used for its pozzolanic properties, which enhance the mechanical and durability characteristics of concrete. Six POFA samples were analyzed after undergoing drying, cutting, grinding, crushing, and calcination at temperatures ranging from 500 °C to 1000 °C. SEM-EDS/EDX analysis, X-ray fluorescence (XRF), and loss on ignition (LOI) tests were conducted to characterize its pozzolanic potential. The results revealed that the SiO content increased with the calcination temperature, reaching a peak of 76.8% at 1000 °C. However, calcination at 600 °C was identified as the optimal temperature, as it balances impurity removal without inducing the formation of crystalline silica, which would negatively affect the material's reactivity. Considering the optimal calcination temperature and the high initial LOI values, which exceeded 70% in the first calcination stage, a second calcination was performed on the 500 °C sample by increasing the temperature to 600 °C. This resulted in an LOI of 3.33%, according to ASTM C311 standards for natural pozzolans used in Portland cement concretes.
油棕核壳灰（POFA）是哥伦比亚高度发达的农业工业部门的一种副产品，因其火山灰特性而被广泛使用，这种特性可增强混凝土的机械性能和耐久性。对六个POFA样品进行了干燥、切割、研磨、粉碎以及在500℃至1000℃温度范围内的煅烧处理后进行了分析。进行了扫描电子显微镜-能谱仪/能量色散X射线光谱仪（SEM-EDS/EDX）分析、X射线荧光（XRF）分析以及烧失量（LOI）测试，以表征其火山灰活性潜力。结果表明，SiO含量随煅烧温度升高而增加，在1000℃时达到峰值76.8%。然而，600℃的煅烧温度被确定为最佳温度，因为它在去除杂质的同时不会诱导结晶二氧化硅的形成，而结晶二氧化硅会对材料的反应活性产生负面影响。考虑到最佳煅烧温度以及在第一次煅烧阶段初始烧失量值较高（超过70%），对500℃的样品进行了第二次煅烧，将温度提高到600℃。根据用于波特兰水泥混凝土的天然火山灰的ASTM C311标准，这使得烧失量为3.33%。
