Impact of WO<sub>3</sub>-Nanoparticles on the Setting Time and Early Strength for Different Cementitious Materials

Abstract

Generally, the setting time and early strength of the cementitious materials are good indications to identify their suitability to be employed as binding materials. Due to the high surface area of nanomaterials, it is considered one of the optimal solutions to modify these properties. Accordingly, this work is focused on comparing the impact of laboratory-prepared tungsten oxide nanoparticles (WO 3 -NP) on two cementitious materials: OPC and alkali-activated slag (AAS). The initial/final-setting time and early compressive strength up to 28-days of the OPC and AAS specimens, modified with 1, 2 wt.% WO 3 -NP, were investigated. The results displayed that WO 3 -NP has a significant impact on the acceleration of the initial/final-setting time of both binding materials. Moreover, the optimal dosage from WO 3 -NP (1 wt.%) upgraded the compressive strength by 19.5 and 15.1% for OPC and AAS, respectively after 7 days. The nucleation-seeds and nano-filler effect of WO 3 -NPs are the focal explanations behind improving these properties via the formation of strength-giving phases and then obtaining a compact microstructure as proved by XRD and SEM.