Introduction and Understanding Fly Ash Bricks

What is Fly Ash?

Fly ash is a fine, powdery residue that is generated as a byproduct during the combustion of pulverized coal in coal-fired power plants. It is composed of inorganic mineral matter present in the coal, which becomes airborne during the combustion process and is captured by pollution control devices such as electrostatic precipitators.

Here are some key points about fly ash:

1. Composition of fly Ash: Fly ash mainly consists of silicon dioxide (SiO2), aluminum oxide (Al2O3), iron oxide (Fe2O3), calcium oxide (CaO), and other minor elements.

2. Types of fly ash: There are two main types of fly ash: class F and class C.

• Class F fly ash is produced from burning anthracite or bituminous coal and is typically low in calcium content. ( Good for manufacturing concrete products )
• Class C fly ash is generated from burning sub-bituminous or lignite coal and contains higher amounts of calcium. ( Class F fly ash typically requires the addition of an activator, such as lime )

3. Pozzolanic properties: Fly ash is known for its Pozzolanic properties, which means it can react with calcium hydroxide in the presence of moisture to form cementations compounds. This reaction contributes to the strength and durability of concrete when fly ash is used as a partial replacement for cement.

What are Fly Ash Bricks?

Fly ash bricks are building materials that are produced by utilizing fly ash, with addition of cement, sand, and water.

Here are some key points about fly ash bricks:

• Composition: Fly ash bricks are primarily composed of fly ash, Cement acts as a binder, while sand provides additional strength and workability. Water is used for hydration and to form a homogeneous mixture for molding the bricks.