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Preparation, characterization and reaction kinetics of green cement: Ecuadorian natural mordenite-based geopolymers

Abstract:

This study was carried out to develop geopolymers derived from mordenite-rich tuffs. First the synthesis of mordenite-based geopolymer was explored through the mix design of three chemical reagents: NaOH, Na4Si5O12, and Ca(OH)2 and varying curing temperature. All the types of synthesized geopolymers were characterized by FT-IR spectroscopy, quantitative X-ray diffraction, SEM–EDS, TGA–DSC, compressive strength. The best mix design and curing temperature by means of the highest compressive obtained after 24 h were found as NaOH: 10 M, Na4Si5O12/NaOH ratio: 0.5, Ca(OH)2: 3% (w/w), and 60 °C, respectively, which showed values of compressive strength about 10 MPa. Then early age reaction kinetics was established using Avrami–Erofe’ev model. The carbonation, as side effect of reactive ingbkp_redient, was also observed during the experiment seemingly without causing any effect on mechanical properties of geopolymers.