Electrical utilities in the United States generate 80
million tons of fly ash as a by-product each year, primarily
from coal combustion [1]. Fly ash is typically disposed in
landfills, but it is preferred to convert fly ash to a construction
material [1,2]. The use of fly ash as an admixture or as a
cement replacement results in improved resistance to alkali–
silica reaction, sulfate attack and corrosion of steel
reinforcement, partly due to the refinement of the pore
structure, the higher retention of alkalis, the formation of
secondary calcium silicate hydrate, and the lower content of
free Ca(OH)2 [3–6]. Moreover, it results in increased
abrasion resistance [7], decreased carbonation depth [8],
reduced heat evolution during curing [9], and enhanced
chemical resistance [10,11]. This article provides a new
application for fly ash, namely, the use of fly ash as an
admixture for enhancing the electromagnetic interference
(EMI) shielding.