introduction

Aggregate is a rock like material, used in many civil engineering and construction applications including:

§  Portland cement concrete

§  Asphalt concrete

§  Base materials for roads

§  Ballast for railroads

§  Foundations

§  Plaster, mortar, grout, filter materials, etc.

Used over 2,000,000,000 tons/yr.

ASTM (American Society for Testing and Materials) C 125 & D 8 are standard definitions

Granular material such as:

  §  Sand & Gravel

  §  Crushed stone

  §  Iron ore blast furnace and other slags

  §  Manufactured (lightweight and heavy weight)

  §  Reclaimed (Crushed Portland cement concrete, clay bricks, or any other waste material etc.)

Aggregates in Concrete, Why?

§  Aggregates are the important constituents in the concrete. Aggregates occupy 60 – 75 % of the volume of concrete.

§  Economy is not the only reason for using aggregates, aggregates give a higher volume stability and better durability to concrete. Cement paste alone has no such higher volume stability, strength and durability.

§  Aggregate properties significantly affect the workability of plastic concrete and also the durability, strength, thermal properties, and density of hardened concrete.

§  Aggregate is cheaper than cement and it is, therefore, economical to put into the mix as much of aggregates and as little of cement as possible.