High-Temperature Resistance of Incineration Fly Ash Mineral Powder Cementitious Material.

Abstract

The feasibility of incineration of fly ash and mineral powder as cementitious materials has been studied, and the room-temperature performance has been investigated. To investigate the high-temperature resistance of incineration fly ash mineral powder mortar in fire environments and evaluate its safety in heavy-metal-ion leaching environments, mineral powders with different dosages of incineration fly ash (30, 40, 50, 60, 70%) were selected, and the performance changes as well as heavy-metal-ion leaching at different temperatures (20, 200, 400, 600, 800 °C) were studied. The experimental findings revealed that the compressive strength of incineration fly ash-mineral powder mortar initially increased and subsequently decreased as the dosage of incineration fly ash was augmented. Specifically, when the dosage of incineration fly ash exceeded 50%, a pronounced decline in the mortar's compressive strength was observed. For instance, at an incineration fly ash dosage of 70%, the compressive strength of the mortar at 600 and 800 °C was merely 2.0 and 0.7 MPa, respectively. The hydration products of the incineration fly ash-mineral powder mortar were found to decompose under high-temperature conditions. Moreover, an increase in the dosage of incinerated fly ash resulted in a higher number of internal voids within the mortar, thereby accelerating its damage in high-temperature environments. The specimens incorporating incineration fly ash at dosages within the range of 30 to 40% are capable of sustaining superior mechanical properties subsequent to exposure to high-temperature environments. Moreover, these specimens are in strict compliance with the established standards for hazardous waste treatment.