Study of a Fire-Resistant Plate Containing Fly Ashes Generated from Municipal Waste Incinerator: Fire and Mechanical Characteristics and Environmental Life Cycle Assessment.

The recycling of fly ash from municipal solid waste incineration is currently a global issue. This work intends to examine the viability of a novel recycling alternative for fly ashes as a component of fire-resistant plates. To lessen the quantity of heavy metal leaching, the fly ash was utilized after being washed using a water/fly ash ratio of 2 for one hour. Subsequently, an inexpensive, straightforward molding and curing process was used to create a plate, with a composition of 60%wt of MSWI-FA, 30%wt of gypsum, 0.5%wt of glass fiber and 9.5%wt of vermiculite. The plate exhibited high fire resistance. Furthermore, it demonstrated compression, flexural strength and surface hardness slightly lower than the requirements of European Standards. This allows for manufacturing plates with a high washed MSWI-FA content as fire protection in firewalls and doors for homes and commercial buildings. A Life Cycle Assessment was carried out. The case study shows that a 60% substitution of gypsum resulted in an environmental impact reduction of 8-48% for all impact categories examined, except four categories impacts (marine eutrophication, human toxicity (cancer), human non-carcinogenic toxicity and water depletion, where it increased between 2 and 718 times), due to the previous washing of MSWI-FA. When these fly ashes are used as a raw material in fire-resistant materials, they may be recycled and offer environmental advantages over more conventional materials like gypsum.

Physical, Mechanical and Radiological Characteristics of a Fly Ash Geopolymer Incorporating Titanium Dioxide Waste as Passive Fire Insulating Material in Steel Structures.

This research analyzes whether a titanium dioxide waste (TiO2 waste) can be used as a source material for geopolymers with good fire resistance properties. Samples with different proportions were prepared, replacing fly ashes with titanium dioxide waste on geopolymers (0, 20, 30, 40 and 100% w/w). The activating solution has a Na2O/SiO2 molar ratio of 0.98. Physical (bulk density, moisture content and water absorption) and mechanical (superficial hardness and compressive strength) characteristics have been evaluated. In addition, their thermal behavior at high temperatures (fire resistance, compressive strength at elevated temperature and absorbed energy) has also been evaluated to see if they can be used as fire insulating materials. This work also studies the radiological activity of geopolymer materials. The replacement of FA with WTiO2 increases the bulk density due to its higher specific bulk density. The highest compressive strength values were obtained with a TiO2 waste content between 30 and 40% w/w. The compressive strength decreases at high temperatures, especially when more TiO2 waste is added. When the amount of TiO2 waste is increased, so is the plateau of evaporation, and this, in turn, increases the resistance to fire. Geopolymers containing FA and TiO2 waste do not present radiological problems, although, when the TiO2 waste is increased, the activity index of the geopolymer also rises.