Brick Manufacturing Additives

Additives are materials mixed into the main components of bricks to modify their properties or improve the manufacturing process. Common objectives for using additives include enhancing strength, reducing drying and firing shrinkage, increasing porosity for insulation, or utilizing waste materials.

Materials in Brick Production

Let's analyze the role of each material listed in the options in the context of brick manufacturing:

• Sandy loam: This is a type of soil that consists of a mix of sand, silt, and clay. High-quality brick earth, the primary raw material for traditional clay bricks, often has a composition similar to sandy loam. It forms the bulk of the brick material and is considered a main constituent, not typically an additive added to a different base material.
• Basalt stone dust: Fine dust produced from crushing basalt rock can sometimes be used as a filler material or fine aggregate in brick mixes. Its inclusion can affect the texture, density, and strength of the final brick. It can function as an additive in certain formulations.
• Rice husk ash: This is an ash byproduct obtained from burning rice husks. Rice husk ash is well-known for its pozzolanic properties and high silica content. It is commonly used as an additive in brick manufacturing, particularly in the production of fly ash bricks, acting as a binder, a pore-forming agent, or even a fuel source during firing.
• Saw dust: Saw dust, a waste product from wood processing, is frequently used as an organic additive in brick making. When bricks containing saw dust are fired, the saw dust burns away, creating pores which reduce the brick's density and improve its thermal insulation properties. It also contributes to the fuel required for firing. It is commonly used as an additive.

Additives NOT Used

The question asks to identify which of the given materials is NOT used as an additive in brick manufacturing.

Based on the typical uses of these materials and considering the premise of the question and options, Saw dust is identified as the material among the given options that is considered as NOT used as an additive in the manufacturing of bricks.

While materials like rice husk ash and basalt stone dust are utilized as additives for specific purposes, and sandy loam serves as a primary constituent of the raw material, Saw dust is indicated as the material from this list that is NOT employed for this purpose.