Material Calculators

Aggregates FAQ

What is aggregate?

Aggregate is all the products of a pit or quarry; including sands, gravels and crushed stone.

Is a pit the same as a quarry?

A pit contains loose sands and gravels that are immediately excavated, screened, and transported. A quarry contains bedrock that must be blasted first before it can be crushed into smaller fragments.

What is the difference between sand and gravel and crushed rock?

Sand and gravels are naturally occurring, in pits; whereas crushed rock comes from the blasting and crushing of stone, in a quarry.

Where does sand and gravel come from?

Sand and gravel used to be bedrock that was crushed by movement and melting of glaciers during the last ice age. Deposits are now found near river deltas and at expansions in rivers where flow slows and deposits fall out.

What is riprap?

Riprap is large pieces of rock which have undergone only initial crushing and sizing, or are larger uncrushed pieces. These pieces of rock range in size from 6 to 30 inches in diameter. Riprap is generally used to stabilize slops and shorelines and construct erosion-control structures.

What makes a base product?

A base product is composed of a crushed or naturally coarse rock and sand that is well graded to create, when compacted, a strong stabilized sub grade for streets, concrete slabs or highways.

What is the difference between limestone and gravel?

Limestone is commonly white in color with angular edges. Gravel has several different colors and is generally smooth and rounded.

What are the different sizes of aggregate available?

Aggregates range from small grains of sand to huge boulders.

What happens during the quarrying process?

First the stone is drilled and blasted into smaller pieces. The material then goes through various stages of crushing and screening to produce the sizes and specifications desired by customers. The aggregates are then stored in separate areas to avoid segregation, mixing and product pollution.

What are sources of supply for aggregates?

Aggregates come from three sources: Unconsolidated rock, sand and alluvial materials; sold rock, limestone and hard rock; and recycled materials.