Fly Ash is an environmentally-friendly solution in concrete! It brings down the carbon emissions from Portland cement and is a more durable infrastructure that doesn’t need to be rebuilt as often. Fly Ash is a natural product of the coal combustion process. It’s actually similar to volcanic ash. Many concrete mixes will replace fly ash up to 25 percent but more can be replaced from the concrete. There are many benefits for using fly ash, such as: greater strength, decreased permeability, increased durability, reduced head of hydration (which means less cracking), and reduced efflorescence. Fly ash concrete is also more acid-and fire- resistant. The final color of fly ash in concrete is usually ranging from dark grey to yellowish tan.