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

© 2017, RILEM. 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 ingredient, was also observed during the experiment seemingly without causing any effect on mechanical properties of geopolymers.status: publishe