Crumb rubber
Encyclopedia
Crumb rubber is a term usually applied to recycled rubber from automotive and truck
scrap tires. During the recycling process steel
and fluff is removed leaving tire rubber with a granular consistency. Continued processing with a granulator and/or cracker mill, possibly with the aid of cryogenics
or mechanical means, reduces the size of the particles further. The particles are sized and classified based on various criteria including color (black only or black and white). The granulate is sized by passing through a screen
, the size based on a dimension (1/4") or mesh (holes per inch : 10, 20, etc.). Crumb rubber is often used in astroturf
as cushioning, where it is sometimes referred to as astro-dirt.
Mesh refers to material that has been sized by passing through a screen with a given number of holes per inch. For example, 10 mesh crumb rubber has passed through a screen with 10 holes per inch resulting in rubber granulate that is slightly less than 1/10 of an inch. The exact size will depend on the size of wire used in the screen.
is the largest market for crumb rubber in the United States, consuming an estimated 220 million pounds, or approximately 12 million tires annually. Crumb rubber is also used as ground cover under playground equipment, and as a surface material for running tracks and athletic fields.
Retreaders tire buffings shall consist of clean, fresh, dry buffings from tire retread preparation operations.
No.1 - Tire Granule shall consist of granulated tire crumb, Black Only Guaranteed MetalFree, sized. Magnetically separated materials are not acceptable. Fluff from tire cord removed.
No.2 - Tire Granule shall consist of granulated tire crumb, Black & White Guaranteed MetalFree, sized to minus 40 Mesh. Magnetically separated materials are not acceptable. Fluff from tire cord removed.
No.3 - Tire Granule shall consist of granulated tire crumb, Black Only Magnetically Separated, sized. Fluff from tire cord removed.
No.4 - Tire Granule shall consist of granulated tire crumb, Black & White Magnetically Separated, sized. Fluff from tire cord removed.
No.5 - Tire Granule shall consist of unclassified granulated tire crumb, Sized, Unseparated, not magnetically separated, fluff from tire cord not removed.
Truck
A truck or lorry is a motor vehicle designed to transport cargo. Trucks vary greatly in size, power, and configuration, with the smallest being mechanically similar to an automobile...
scrap tires. During the recycling process steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
and fluff is removed leaving tire rubber with a granular consistency. Continued processing with a granulator and/or cracker mill, possibly with the aid of cryogenics
Cryogenics
In physics, cryogenics is the study of the production of very low temperature and the behavior of materials at those temperatures. A person who studies elements under extremely cold temperature is called a cryogenicist. Rather than the relative temperature scales of Celsius and Fahrenheit,...
or mechanical means, reduces the size of the particles further. The particles are sized and classified based on various criteria including color (black only or black and white). The granulate is sized by passing through a screen
Mechanical screening
Mechanical screening, often just called screening, is the practice of taking granulated ore material and separating it into multiple grades by particle size....
, the size based on a dimension (1/4") or mesh (holes per inch : 10, 20, etc.). Crumb rubber is often used in astroturf
AstroTurf
AstroTurf is a brand of artificial turf. Although the term is a registered trademark, it is sometimes used as a generic description of any kind of artificial turf. The original AstroTurf product was a short pile synthetic turf while the current products incorporate modern features such as...
as cushioning, where it is sometimes referred to as astro-dirt.
Mesh refers to material that has been sized by passing through a screen with a given number of holes per inch. For example, 10 mesh crumb rubber has passed through a screen with 10 holes per inch resulting in rubber granulate that is slightly less than 1/10 of an inch. The exact size will depend on the size of wire used in the screen.
Recycled pavement material
Rubberized asphaltRubberized asphalt
Rubberized asphalt concrete , also known as asphalt rubber or just rubberized asphalt, is pavement material that consists of regular asphalt concrete mixed with crumb rubber–ground, used tires that might otherwise be discarded, taking up space in landfills, if they were not re-directed for use as...
is the largest market for crumb rubber in the United States, consuming an estimated 220 million pounds, or approximately 12 million tires annually. Crumb rubber is also used as ground cover under playground equipment, and as a surface material for running tracks and athletic fields.
Description of crumb rubber grading
The following are common classifications of crumb rubber:Retreaders tire buffings shall consist of clean, fresh, dry buffings from tire retread preparation operations.
No.1 - Tire Granule shall consist of granulated tire crumb, Black Only Guaranteed MetalFree, sized. Magnetically separated materials are not acceptable. Fluff from tire cord removed.
No.2 - Tire Granule shall consist of granulated tire crumb, Black & White Guaranteed MetalFree, sized to minus 40 Mesh. Magnetically separated materials are not acceptable. Fluff from tire cord removed.
No.3 - Tire Granule shall consist of granulated tire crumb, Black Only Magnetically Separated, sized. Fluff from tire cord removed.
No.4 - Tire Granule shall consist of granulated tire crumb, Black & White Magnetically Separated, sized. Fluff from tire cord removed.
No.5 - Tire Granule shall consist of unclassified granulated tire crumb, Sized, Unseparated, not magnetically separated, fluff from tire cord not removed.