Fly Ash - An Important Ingredient for use in Hot-Mix ASHphalt Concrete

Abstract

This paper presents an overview of laboratory and field demonstration work with beneficial use of fly ash in hot-mix asphalt. The blend of asphalt binder and fly ash is named "ASHphalt". The field demonstration took place at We Energies, an electric, gas and steam utility headquartered in Milwaukee, Wisconsin, USA. Environmental sustainability benefits include conservation of energy and natural resources as well as reducing CO2 and other environmental impacts. Economic and social benefits include development of construction technologies for longer life pavements with reduced maintenance costs, and reduced impacts for pavement users. The benefits of ASHphalt include: improved workability, easier compaction to specified density, improved binder aging resistance, a reduction in age-related cracking, extending the asphalt binder or reduction of binder content, a reduction in binder related issues, thermal stress relief, and reduced potential for thermal cracking. This paper shares the results of some laboratory testing and field demonstration work.

Performance of Porous Asphalt Mixtures Containing Recycled Concrete Aggregate and Fly Ash

“…The degradation of RCA increased the number of fine particles, which may fill up more voids in the mixture. The impact of fly ash may be explained by its unique features of spherical shape, good size distribution, and chemical properties, which helped to improve the rheological properties and workability of the hot mix asphalt [20,48].…”

“…Polymer modification can be used to improve the performance of asphalt. This technology, however, is expensive due to the high cost of polymers used in the process [20]. Instead, by incorporating additional byproducts such as fly ash, asphalt mixtures with RCA may have improved strength and moisture resistance.…”

“…In the literature, previous research on the use of fly ash in asphalt mixtures showed that the addition of fly ash improved the workability of HMA during construction and increased its durability and resistance to water and freeze-thaw damage [21]. It was deemed that the unique spherical shape, good size distribution, and chemical properties of fly ash contributed to the enhanced performance of asphalt mixtures [20]. Although attention has been paid to using fly ash, primarily as a filler, in asphalt mixtures, most work to date has been on the use of fly ash in DGA mixtures, and the application of fly ash in asphalt pavement construction is still limited [22].…”

Laboratory Evaluation of the Properties of Asphalt Mixture with Wood Ash Filler

“…Fly ash made by the combustion of coal in thermal power plants found their application in asphalt mixtures first [23][24][25][26]. Various applications of this type of ash were the most and longest researched.…”