Influence of size reduction of fly ash particles by grinding on the chemical properties of geopolymers

Chemical properties of geopolymers were evaluated from the reduction of fly ash particle size by grinding. X-ray diffraction determined that at early curing ages new crystalline phases appear in the matrix of the geopolymer and they remain for 28 days, with increases in intensities up to 60%. In Fourier transform infrared spectroscopy, displacements were identified in the main band of the geopolymers at higher wavenumbers, attributed to the greater rigidity in the structures of the aluminosilicate gel due to the increase of the reaction products in the geopolymers obtained through fly ashsubjected to previous grinding, which is observable in the geopolymers matrix. Results indicate that the reduction of fly ash particle size by grinding has an influence on the chemical properties of geopolymers.Peer ReviewedPostprint (published version

Strength, elastic properties and fiber–matrix interaction mechanism in geopolymer composites

The current geopolymers have limited mechanical strength against the effect of tension, which makes them susceptible to brittle failure. However, owing to their potential as a sustainable construction material, there is growing interest in improving the poor mechanical properties of geopolymers. This study experimentally investigated crucial properties of polypropylene-fiberreinforced fly ash-based geopolymer composites. The effects of polypropylene fibers (PPF) addition (0.5%, 1.0% and 1.5% by volume) on the mechanical properties of the geopolymer composites were investigated with respect to compressive and flexural strength, deformation behavior of Young’s and shear moduli, and resilience capacity. In addition, scanning electron microscopy was performed to establish the morphology of the geopolymeric matrix and the fiber–matrix interfacial interaction. The addition of PPF significantly increased the flexural strength: compared with the control, at 7 days it was 27% greater for the 0.5% PPF composite and 65% greater for the 1.0% PPF composite. By 14 days it was 31% and 61% greater, respectively. By contrast, the 1.5% PPF composite had lower strength parameters compared with the control because the fiber dispersion increased the porosity. Similar trends were seen for resilience. The SEM observations showed the dispersion of the fibers and helped elucidate the fiber–matrix interaction mechanismPeer ReviewedPostprint (published version

EFFECT OF CURING TEMPERATURE IN THE ALKALI-ACTIVATED BLAST-FURNACE SLAG PASTE AND THEIR STRUCTURAL INFLUENCE OF POROSITY

Due to the environmental problem posed by the use of Portland cement as construction material, it becomes necessary the search for supplementary cementitious materials that mitigate the ecological damage caused by it. Because the chemical similarity and the high cementitious powers of the blast furnace slag, it is used in the generation of geopolymers in a cement total replacement. This research focused on the study of the influence of the curing conditions on the final properties of blast furnace slag establishing three variables: no cured process (N-C), cured of controlled temperature of 45°C (CT45-C) and room temperature cure (RT-C); evaluating the mechanical behavior until 28 days of age and the water porosity index. The results show that geopolymers based on blast furnace slag has a behavior similar to hydration maturity of Portland cement and curing process decreases the porosity; On the other hand, applying a controlled temperature generates densest resistant pastes such as the variable CT45-C which reach the highest value of resistance in all curing ages

Effect of curing temperature in the alkali-activated blast-furnace slag paste and their structural influence of porosity

Due to the environmental problem posed by the use of Portland cement as construction material, it becomes necessary the search for supplementary cementitious materials that mitigate the ecological damage caused by it. Because the chemical similarity and the high cementitious powers of the blast furnace slag, it is used in the generation of geopolymers in a cement total replacement. This research focused on the study of the influence of the curing conditions on the final properties of blast furnace slag establishing three variables: no cured process (N-C), cured of controlled temperature of 45°C (CT45-C) and room temperature cure (RT-C); evaluating the mechanical behavior until 28 days of age and the water porosity index. The results show that geopolymers based on blast furnace slag has a behavior similar to hydration maturity of Portland cement and curing process decreases the porosity; On the other hand, applying a controlled temperature generates densest resistant pastes such as the variable CT45-C which reach the highest value of resistance in all curing ages.Peer Reviewe

Influence of size reduction of fly ash particles by grinding on the chemical properties of geopolymers

Chemical properties of geopolymers were evaluated from the reduction of fly ash particle size by grinding. X-ray diffraction determined that at early curing ages new crystalline phases appear in the matrix of the geopolymer and they remain for 28 days, with increases in intensities up to 60%. In Fourier transform infrared spectroscopy, displacements were identified in the main band of the geopolymers at higher wavenumbers, attributed to the greater rigidity in the structures of the aluminosilicate gel due to the increase of the reaction products in the geopolymers obtained through fly ashsubjected to previous grinding, which is observable in the geopolymers matrix. Results indicate that the reduction of fly ash particle size by grinding has an influence on the chemical properties of geopolymers.Peer Reviewe

Estudios multidisciplinarios en Ciencias de la Salud

Es una distinción, como miembro de la Comisión del Programa del Doctorado en Ciencias de la Salud de la Universidad Autónoma del Estado de México, presentar el libro titulado Estudios multidisciplinarios en Ciencias de la Salud, en el que distinguidos y reconocidos investigadores, entusiastas y comprometidos alumnos del programa nos dan a conocer los resultados de sus proyectos de investigación, trabajos que forman parte de los requisitos para acceder al grado de doctor. Entre las razones que invitan a la lectura del libro destaca su contenido conformado con la participación de autores en cuatro áreas en el campo de la salud: Odontología, Ciencias Médicas y Nutrición, Ciencias de la Conducta, y Enfermería y Obstetricia, quienes contribuyen a incrementar el acervo del conocimiento en cada área, en favor de la ciencia, la tecnología, y la salud física y mental de la población.Universidad Autónoma del Estado de México