Abstract
In this research, the enhancement of the pozzolanic activity of cinder ash was evaluated using pulverized raw cinder ash particles. Since the sum of SiO2+Al2O3+Fe2O3 of pulverized cinder ash (PCA) was >70% and based on the results of XRD analysis, it could be classified as Class F fly ash (FA). Also the chemical composition and mineralogical characteristics of PCA was similar to FA. But the shape of PCA particles differed from those of FA particles, as the pulverized particles were rougher in texture and has sharp edges than FA particles, which have round shape and smooth surfaces. From the results of the mechanical properties development and compressive strength values, it could be considered that the addition of 20% PCA, as cement replacement in concrete produced the best effects. The X-ray diffraction and scanning electron microscopy techniques revealed that the PCA had satisfactory pozzolanic activity though a bit lower than FA. This is because of insufficient formation of C-S-H and C-A-S-H gels even with a high consumption of CH. The pozzolanic activity of fly ash was much greater than PCA due to the higher glassy phase and round finer particles of fly ash. Therefore, the 20% of cement content replaced by PCA was better than 30% replacement, with fly ash the 30% replacement ratio was preferred.
