In Kerala, blue metal, also known as crushed stone or aggregate, is a vital component in construction, serving as a key material in various applications. Here are some common types of blue metals used in construction in Kerala:

1. 20mm Blue Metal: This is one of the most commonly used types of blue metal in construction projects across Kerala. It is typically used as a coarse aggregate in concrete mixtures for applications such as foundation bases, floorings, and structural elements. The 20mm size is ideal for providing strength and stability to concrete structures.

2. 6mm Blue Metal: Smaller in size compared to 20mm blue metal, 6mm blue metal is often used as a fine aggregate in concrete mixtures, mortar, and plastering works. Its smaller size allows for better bonding between particles, resulting in a smoother finish for surfaces such as walls and ceilings.

3. Quarry Dust (Blue Metal Dust): Quarry dust, also known as blue metal dust or crusher dust, is a by-product of crushing blue metal rocks in quarries. It is commonly used as a filler material in construction applications where a compacted base is required, such as under paving stones, roadways, and pathways. Quarry dust can also be mixed with cement to improve the strength and workability of concrete mixtures.

4. Crusher Run (Blue Metal Aggregate): Crusher run is a type of blue metal aggregate that is mixed with fine particles, ranging from dust to 20mm in size. It is commonly used as a base material for road construction, driveways, and pathways due to its excellent compaction properties and ability to provide a stable foundation.

5. Manufactured Sand (M-Sand): While not technically a type of blue metal, manufactured sand (M-sand) is often used as a substitute for natural river sand in construction projects in Kerala. M-sand is produced by crushing hard granite rocks into fine particles and is widely used in concrete production, plastering, and masonry works due to its consistent quality and particle shape.