Aggregate Terminology

Natural Aggregates:  Aggregates originated from  stone  quarries,  gravel, sand or igneous/ metamorphic rock deposits.

Slag Aggregates:  By-products formed  in  the production  of  iron,  copper, and steel.

Iron   Blast   Furnace   Slag:  A  synthetic  nonmetallic  by-product simultaneously  produced  with  pig  iron in  a  blast  furnace  that  primarily consists of a fused mixture of oxides of silica, alumina, calcium, and magnesia.

Reverberator Furnace Slag:  A non-metallic  by-product  of  refined  copper ore.

Steel  Furnace Slag:  A  synthetic  by-product  of  basic  oxygen, electric or open-hearth steel furnaces that primarily consists of a  fused  mixture  of  oxides  of  calcium,  silica,  iron,  alumina,  and  magnesia.

Crushed Concrete Aggregate:  Crushed portland cement concrete.

Salvaged    Aggregate:  Dense-graded  aggregate   saved   or   manufactured from Department project sources that may consist of  natural  aggregate,  blast  furnace  slag,  crushed  concrete,  or  reclaimed  asphalt  pavement  with  particle  sizes  no  greater  than  2 inches and no visible organic or foreign matter.

Manufactured  Fine  Aggregate:  One  hundred  percent  crushed  rock,  gravel,  iron  blast  furnace  slag,  reverberatory  furnace  slag,   steel furnace slag, or portland cement concrete.

Natural  Sand  2NS  and  2MS:  Fine,  clean,  hard,  durable,  uncoated  particles of sand free from clay lumps, and soft or flaky granular material  resulting  from  the  natural  disintegration  of  rock,  and used  in  concrete  mixtures,  mortar  mixtures,  and  intrusion  grout  for pre-placed aggregate concrete.

Stone  Sand  2SS: Sand  manufactured  from  stone  sources.    These  stone  sources  must  meet  the  physical  requirements  for  coarse  aggregate  6A  prior  to  crushing.    The Engineer  will  only  allow  stone  sand  in  concrete  base  course  or  structural  concrete  not  exposed to vehicular traffic.

Soft Particles: Structurally weak particles or particles experiencing environmental deterioration, including  shale,  siltstone,  friable  sandstone, ochre, coal, and clay-ironstone.

Crushed Particles:  Particles  with  at  least  one  fractured  face.    The contract  will  specify  the  number  of  fractured  faces  based  on  required  use.    Unless otherwise  specified,  one  fractured  face  is considered a crushed particle.

Base Fineness Modulus:  The average fineness modulus typical of the source for a specific fine aggregate.

Cobblestones (Cobbles): Rock  fragments,  usually  rounded  or semi-rounded, with an average dimension between 3 inches and 10 inches.