Natural zeolite-based geopolymers as alternative building materials

In recent years, the use of natural zeolites to synthesize geopolymer composites (pastes, mortars and concretes) has gained increasing interest among researchers seeking to replace partially or totally the use of ordinary Portland cement. The main objective of this paper is to broaden the information available on the development of alternative materials, for which the present research prepared samples of natural zeolite-based geopolymer mortar as a possible building material application, in which their mechanical properties were evaluated in terms of compressive strength. Additionally, the mix design was optimized by using two alkali activators (NaOH 14M and Na2SiO3) in different proportions, river sand as fine aggregate, and curing time and temperature. All samples were characterized by quantitative X-ray diffraction, SEM-EDS, simultaneous TGA-DSC analysis and compressive strength. The results showed that the best mix corresponds to NaOH: 14M, Na2SiO3/NaOH: 3, activator/zeolite: 0.5, sand/zeolite: 1.5, cured at 60 degrees C, which showed a compressive strength increase (17.3 MPa) at an early age as well as in the long term.