Investigation on the mechanical and microstructural properties of meta-halloysite-based geopolymer mortars cured at room temperature

In this study, meta-halloysite (MH) mixed with an alkaline solution (8, 10, and 12 M) was used as a binder phase to produce geopolymer mortars with alkaline solution/MH ratios of 0.6, 0.7, and 0.8. The flow slump behaviour, setting time, and mechanical properties of the end products were studied at room temperature. The microstructural properties of the geopolymer mortars were evaluated using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. The matching slump values of fresh geopolymer mortars dropped as the alkaline solution concentration increased. The initial setting time increased as the alkaline solution/MH ratio grew (from 0.6 to 0.8). Increasing the alkaline content above 0.6 was averse to the development of strength and densification of the structure. The geopolymer mortar sample made with 0.6 and 12 M NaOH had a high compressive strength (65 MPa), low porosity, and low water absorption. According to the current study findings, geopolymer mortar has demonstrated great practicality and application potential for usage as an environmentally friendly building material, which may be a viable alternative for typical cement mortar in the future.