Cement Hydration Extents for Hardened Cement Paste Incorporating Nanosized-Palm Oil Fuel Ash: A Thermal and XRD Analysis Study

Abstract

The suitability of nanosized-POFA (nPOFA) as a supplementary cementing material has not been discovered enough. Therefore, the present study investigates the degree of cement hydration of Hardened Cement Paste (HCP) incorporating nPOFA via thermal and XRD analysis. The nPOFA was prepared by grinding the micro-POFA (mPOFA) using ceramic ball milling for 30 h. A series of Hardened Cement Paste (HCP) incorporating 10–60% of nPOFA and 10–30% of mPOFA were prepared and examined at 28- and 90-day curing age. The hydration of cement was assessed by monitoring the dehydroxylation of portlandite (CH) through Thermogravimetric Analysis (TGA) and X-ray Diffraction (XRD) analysis. The prepared nPOFA possesses average crystallite size calculated from the XRD diffractogram which is 34.74 nm, and BET surface area of 145.35 m2/g. Based on the TG analysis, the HCP with 30% nPOFA replacement gives the highest CH consumption in the HCP within the interval time of two curing ages. Significantly, it indicates that 30% nPOFA replacement in HCP accelerates the hydration of cement through the pozzolanic reaction between the amorphous silica and CH from the hydrated products. Meanwhile, the XRD analysis indicated a decrease in CH peaks intensity in nPOFA HCP, which corresponds to the consumption of CH in the pozzolanic reaction. The results show that the high fineness of nPOFA results in the high distribution in HCP and rapid dissolution as it increases the rate of pozzolanic reaction.