Abstract

This study examines the structural evaluation of differently activated kaolins for potential use as supplementary cementitious materials (SCM) or as precursor for alternative cementitious materials (ACM). Chemical activation involved amorphizing the kaolinite structure using varying phosphoric acid concentrations, reaction times, and temperatures. Metakaolin obtained via thermal activation served as a comparison. Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES) characterization of the activating solutions revealed phosphoric acid activation leading to dealumination in kaolinite structures, with temperature emerging as the most significant parameter. X-ray diffraction (XRD) confirmed amorphization, attributed to the dealumination process causing Al loss and creating new Si–O–Si interlayered bonds, as monitored by 29Si magic-angle spinning nuclear magnetic resonance (MAS NMR) tracking the change from Q3 to Q4 environments. Furthermore, pozzolanic activity was assessed through Ca(OH)2 consumption and reaction heat release via modified Chapelle and R3 tests, respectively. Kaolinite subjected to intensive chemical activation exhibited high reactivity and increased specific surface area, indicating its potential as a pozzolanic material. Keywords: Kaolin; Chemical activation; Supplementary cementitious materials; Alternative cementitious materials; Dealumination; Pozzolanic reactivity.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.