Production of silica fume-based geopolymeric foam

Shakouri, Sahra
This study investigates the activation of silica fume powder with sodium hydroxide solutions, to produce foamy geopolymeric material. The powder was mixed with NaOH solutions of different concentration, at different solution-to-powder ratios and cured at 100 °C for different length of time. Upon to heating to 200-500 °C, a volume expansion up to 10 times of the initial paste volume took palace, and a porous structure resulted. Ground perlite, expanded perlite and basalt fibers were tested as additives to the initial mixtures. The main goal of this study was to reach a uniform foamy structure with as low density as possible. The final density of materials decreased to as low as ~50 kg/m3. The morphological characteristics of samples were investigated by SEM analyses performed on heat treated products. Compressive strength of expanded materials ranges between 50 kPa and 1 MPa. Also the structural evolution of pastes was determined using FTIR spectroscopy and 29Si MAS NMR measurements. Pore size distribution and pore volumes measured by nitrogen adsorption and x-ray microcomputed tomography.


Production of lightweight aerated alkali-activated slag pastes using hydrogen peroxide
Sahin, Murat; Erdoğan, Sinan Turhan; Bayer, Özgür (Elsevier BV, 2018-08-30)
This study investigated the production of lightweight aerated alkali-activated slag pastes (LAAASP) using hydrogen peroxide (H2O2). A mixture of sodium hydroxide and sodium silicate solution was used for the activation of slag. Physical, mechanical, and thermal properties of samples cured under different curing conditions were investigated. Various water-to-slag ratios (W/S) and H2O2 contents were used to explore the expansion mechanism of fresh mixtures and to investigate their effect on apparent density. ...
Effects of nanoclays on the flammability of polystyrene with triphenyl phosphate-based flame retardants
Kaynak, Cevdet (SAGE Publications, 2013-07-01)
The main purpose of this study is to investigate the effects of nanoclays on the flammability behavior of neat polystyrene and polystyrene compounded with traditional flame retardants triphenyl phosphate and its synergist melamine cyanurate. Nanocomposites were prepared via ultrasound-assisted solution intercalation technique. Dispersion and nanomorphology of nanoclays were investigated through X-ray diffraction analysis and transmission electron microscopy. Thermal stability and flammability behaviors were...
Characterization of Ti-6Al-4V alloy foams synthesized by space holder technique
ESEN, ZİYA; Bor, Sakir (2011-03-25)
Ti-6Al-4V foams, biomedical candidate materials, were synthesized by powder metallurgical space holder technique as a result of evaporation of magnesium to achieve desired porosity content. Final products contained porosities in the range similar to 43-64% with an average macropore size between 485 and 572 mu m and a lamellar type Widmanstatten microstructure composed of alpha-platelets and beta-laths. Unlike the case of bulk Ti-6Al-4V alloy tested under compression loading, compression stress-strain curves...
Investigation of single-walled carbon nanotube growth parameters using alcohol catalytic chemical vapour deposition
Ünalan, Hüsnü Emrah (2005-10-01)
A detailed parametric study of single-walled carbon nanotubes (SWNTs) synthesized in powder form and on substrates using the alcohol catalytic chemical vapour deposition (ACCVD) method is reported. As-grown SWNTs were analysed using transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy and UV-vis-NIR spectroscopy to obtain structural and electronic information. We found that nucleation and growth of SWNTs occurs within seconds after introduction of ...
Use of boron oxide and boric acid to improve flame retardancy of an organophosphorus compound in neat and fiber reinforced polyamide-6
POLAT, Osman; Kaynak, Cevdet (2016-09-01)
The aim of this study was to investigate the usability of boron oxide and boric acid to enhance flame retardancy of (aluminum diethyl phosphinate)-type organophosphorus compound in polyamide-6 and its 15 wt% of short (glass fiber)-reinforced composite. Materials were compounded by melt-mixing method via a twin-screw extruder, and the specimens for testing and analyses were shaped by injection and compression-molding. For the neat polyamide-6 specimens, mass loss cone calorimetry analyses indicated that repl...
Citation Formats
S. Shakouri, “Production of silica fume-based geopolymeric foam,” M.S. - Master of Science, Middle East Technical University, 2017.