INFLUENCE OF CURING METHOD AND ALKALINE ACTIVATORS RATIO ON THE GEOPOLYMERS COMPOSITION AND COMPRESSIVE STRENGTH

Reference	Presenter	Authors (Institution)	Abstract
04-098	Andreia De Rossi	De Rossi, A.(Universidade Federal de Santa Catarina); Ribeiro, M.J.(Instituto Politécnico de Viana do Castelo); Novais, R.M.(Universidade de Aveiro); Labrincha, J.A.(Universidade de Aveiro); Hotza, D.(Universidade Federal de Santa Catarina); Moreira, R.d.(Universidade Federal de Santa Catarina);	In this work, the influence of distinct curing methods on the properties of geopolymers was evaluated. Five cure methods were evaluated varying temperature (ambient and 40 °C) and containers (open, sealed and sample submerged in water). Geopolymeric pastes were obtained with 75 wt.% fly ash and 25 wt.% metakaolin, by using two alkali activators ratios (Na2SiO3/NaOH = 1.0 and 1.5). Characterization involved XRF, SEM, XRD, TGA and compression tests performed after 28 days. Results show that higher amounts of sodium silicate improved the compressive strength of the geopolymers for all curing methods. The highest increase (from 9 MPa to 24 MPa) was obtained at 40 °C in open container. Changes in the phase composition of the developed geopolymers were observed, with zeolite P being found in the curing method in sealed container at 40 °C and Na2SiO3/NaOH = 1.0. In this geopolymer the highest total porosity (62.38 ± 0.58%) was obtained, reflecting in compressive strength of 9.77 ± 0.96 MPa. The other geopolymers studied with the different curing methods showed porosity between 50 - 57% and closed porosity between 6-14%, with water absorptions between 40 - 47%. Thus, the study of different curing methods and concentrations of alkaline activators allowed the production of geopolymers with different characteristics and applications.
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