Fly Ash-Based Geopolymer: Green Material in Carbon-Constrained Society

Abstract

Climate change is recognized as a global problem and even the industrial and construction sectors are trying to reduce the green-house gas emissions, especially on CO2 emissions. In Vietnam, the coal-fired thermal power plants are discharging millions of tons of CO2 and coal ash annually. This coal ash is comprised of about 80% of fly ash and the rest is bottom ash. This study would like to introduce one of the potential solutions in a carbon-constrained society that would not only manage the fly ash but also utilized this as raw material for green materials through geopolymerization. The geopolymer-based material has lower energy consumption, minimal CO2 emissions and lower production cost as it valorizes industrial waste. The fly ash containing high alumino-silicate resources from a coal-fired power plant in Vietnam was mixed with sodium silicate and sodium hydroxide solutions to obtain the geopolymeric pastes. The pastes were molded in 10x10x20cm molds and then cured at room temperature for 28 days. The 28-day geopolymer specimens were carried out to test for engineering properties such as compressive strength (MPa), volumetric weight (kg/m3), and water absorption (kg/m3). The microstructure analysis was also conducted for this eco-friendly materials using X ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Differential Thermal Analysis - Thermal Gravimetric Analysis (DTA-TGA).

Đánh Giá Đặc Tính Kỹ Thuật Của Bê Tông Tro Bay Cao Sử Dụng Phụ Gia Vôi Và Silica Fume

“…Vật liệu pozzolanic có khả năng đóng rắn hay cứng lại với nước nhờ hoạt hóa với chất kiềm như vôi [5]. Đặc tính thủy hóa này làm cho tro bay có thể thay thế xi măng trong các cấp phối bê tông và nhiều ứng dụng xây dựng khác [6,7]. Ngày nay, tro bay được sử dụng nhiều trong bê tông và các sản phẩm nền xi măng khác, làm nền đường, chất ổn định dầu, chất độn sạch, chất độn trong nhựa đường, thu hồi kim loại, và chất độn khoáng khác [5,7].…”

Study of the Mechanical Properties and Microstructure of Alkali-Activated Fly Ash–Slag Composite Cementitious Materials

“…However, due to the low activity of fly ash, as well as its slow reaction curing, it needs to be cured under high temperatures, high levels of humidity, and other environmental conditions, and it has poor anti-permeability. Moreover, the composition of different types of fly ash varies, so the performance of the prepared alkali-activated materials varies greatly, which limits the actual use of alkali-activated fly ash materials in engineering [12][13][14][15][16][17]. Nath et al [18] and Ling et al [19] found that the incorporation of a certain amount of slag in an alkali-activated fly ash system can effectively improve the defects that exist in single use conditions.…”

Fabrication of Transparent Composites from Pinaceae Wood Packaging Residues

“…Meanwhile, the types of domestic waste are sorted, mixed with additives and then they are composted in many days to produce fertilizer for the agricultural production. For the industrial solid waste, the recycling has still faced to many difficulties due to the variety of origins, containing many different components included hazards and toxic substances or heavy metals [9][10][11][12][13][14]. This is a big obstacle for the recycling and use of the industrial solid waste as raw materials for other industries.…”