Fly ash is typically finer than Portland cement and lime. Fly ash consists of silt-sized particles which are generally spherical; typically ranging in size between 10 and 100 micron These small glass spheres improve the fluidity and workability of fresh concrete. Fineness is one of the important properties contributing to the pozzolanic reactivity of fly ash. Under a microscope, they look like tiny bubbles of various sizes. The annual generation of fly ash has increased from about 1 million tonnes in 1947 to about 40 million tonnes during 1994 and to about 112 million tonnes at present. As per an estimate of FAUP, TIFAC, the annual ash generation figures are expected to reach about 170 million tonnes by 2012 and 225 million tonnes by 2017. Over a period of the last ten years, the image of fly ash has completely been changed from a ¿Polluting Waste¿ to ¿Resource Material¿. The economic worth of fly ash has been understood by the people Use of Fly ash for Road Embankment Fly ash Roads and it has now become a ¿sought after material¿.