Effects of circulating fluidized bed combustion (CFBC) fly ashes as filler on the performances of asphalt

Abstract

This work investigated the potential of utilizing circulating fluidized bed combustion (CFBC) fly ashes (CFAs) as alternative filler, substituting mineral powders (MPs) that are widely used in asphalt concrete. Physicochemical characteristics of the CFAs and MPs, as well as effects of different mix designs of CFAs and asphalt on asphalt performances were examined, including moisture susceptibility, viscosity, ductility, softening point, penetration, and antiaging performances. The results of the study show that generally the CFAs have greater effects than the MPs on improving the performances of asphalt, and that the specific surface area (SSA), free CaO (f-CaO), morphology, and mineralogical phases of the CFAs are more favorable than those of the MPs respectively, while the alkaline values, hydrophilic coefficients, particle size distributions (PSDs), and water contents of the two fillers are similar. It is suggested that CFAs may be more suitable than MPs for the use as asphalt concrete filler. 

Utilization of Fly Ashes from Fluidized Bed Combustion: A Review

“…FBCFA has been found to be more suitable for asphalt concrete than virgin mineral powders. Li et al [170] investigated the potential of utilizing FBCFA as an alternative filler, substituting mineral powders that are widely used in asphalt concrete. Their results showed that generally FBCFAs have a greater effect on improving the performances of asphalt and that the specific surface area, free CaO, morphology, and mineralogical phases of the FBCFAs are more favorable than those of the mineral powders, respectively, while the alkaline values, hydrophilic coefficients, particle size distributions, and water contents of the two fillers are similar.…”

Low-reactive circulating fluidized bed combustion (CFBC) fly ashes as source material for geopolymer synthesis

“…Normally, CFAs conform to neither North American standards nor European ones for components or additives in concretes (Blondin and Anthony, 1995). The unique thermal history, featuring low combustion temperatures of 800-950°C, makes CFAs differ greatly in physical and chemical characteristics from PFAs, whose typical firing temperatures are 1200-1400°C (Anthony et al, 2002;Li et al, 2009). Eventually, the low combustion temperature may lead to a low pozzolanic activity (Iribarne et al, 2001), which is partially responsible for the poor feasibility of utilizing CFAs in cement industry.…”