Abstract
•Unground POFA (UPOFA) was not a suitable cement replacement material.•Incorporating nanosilica (NS) modified microstructure and pozzolanic activity of UPOFA mortars.•Addition of 0.5% NS increased the compressive strength of UPOFA mortars.•Admixing NS augmented the replacement level of UPOFA up to 20%.
The present study focused on enhancing properties of unground palm oil fuel ash (UPOFA) mortars by incorporation of nanosilica (NS). To do so, 0.5–1.5% NS was admixed in each series of 10–30% UPOFA, respectively. The results revealed that incorporating NS offset the adverse effect of UPOFA on flowability, compressive strength and water absorption of mortars. Addition of NS increased the replacement level of UPOFA up to 20% with comparable compressive strength to control sample. SEM and XRD results showed that admixing NS led to improvement in the microstructure, and pozzolanic behavior of UPOFA mixtures at 28days.