Shreds

Tire Derived Aggregate, (TDA)

Tire Derived Aggregate, (TDA) consists of scrap tires cut into pieces that have a basic geometric shape and range between 2” and 12” and are intended for use in civil engineering applications, refer to ASTM D6270-98.

Dresmith Tire Disposal has a class II Scrap Tire Recovery permit. This permit allows us to shred scrap tires to a size of 4”. The TDA shreds are commonly used for civil engineering , public works and by contractors as drainage material. Some of the benefits are:

Lightweight, (weighs 1/3 of what soil weighs)
Low earth pressure (1/2 that of soil)
Good thermal insulation (8 times better than gravel)
Good drainage (10 times better)
Compressible
Vibration mitigation
Low cost

This material has been used in construction application for over 20 years. Attached are two documents describing the benefits as well as the applications. The first publication is from the scrap tire news organization which describes some of the common application using TDA.

The second document included is the ASTM D 6270-98 (reapproved 2004). This is a standard practice of use of scrap tires in civil engineering applications. This standard was created for the government showing all the engineering and testing behind the justification of use for TDA as construction material. The engineering provided proves that the TDA is a better material for many common construction applications with no environmental impact.

Document #1

TDA in Civil Engineering Applications

The majority of civil engineering applications for tire derived aggregate are occurring in the construction industry. Most prominent are TDA uses suitable for construction projects in road building and repair, transportation infrastructure, commercial and residential building and landfill design and construction. These uses are diverse and growing as contractors, engineers, designers and architects in both the public and private sectors realize the engineering properties and the economic and environmental value TDA brings to a project. In addition, new case studies, educational videos and mounting performance and monitoring data from full-scale instrumented projects are contributing to the expanded use of TDA.

There are five primary categories of civil engineering applications for TDA:

1. Road Construction

Highway Embankments : TDA can be used as lightweight fill over weak foundation soils to limit settlement and increase slope stability. Based on the requirements of the project, TDA can also be used as replacement for conventional fill in embankments.
Landslide Stabilization: TDA can be used as lightweight fill at the head of a landslide to reduce the weight pushing the slide downhill.
Road Sub-grade: TDA can be used lightweight fill over weak soils.
Thermal insulation to limit frost penetration: TDA used as an aggregate layer in road beds in cold climates can help mitigate the depth of frost penetration and associated effects that contribute to frost heaves.
Retaining wall and bridge abutment backfill: using TDA as backfill behind retaining walls and bridge abutments reduces lateral forces on the inside of the retaining wall or abutment walls.
Edge drains and pipe trenches: TDA has higher permeability than most granular aggregate and can be used as an effective medium for providing beneficial drainage in edge drains along roadsides, drainage layers beneath roads and in pipeline or other utility line trenches.

2. Septic System Construction

TDA is used as a stone aggregate replacement in the absorption trenches of residential septic systems. TDA has a higher porosity than stone and can increase drain field storage capacity by 30 percent.

3. Light-rail Construction

TDA reduces ground borne vibrations transmitted away from the tracks on commuter rail lines.
Typically, a 1-ft. thick layer of TDA placed under the traditional stone ballast and gravel sub-ballast layers in light rail construction is effective in mitigating vibrations that transmit the noise of the passing train away from the tracks to adjacent homes and businesses.

4. Landfill Construction

Drainage layer in a leachate collection system: TDA is incorporated as a component of the leachate collection system to provide drainage, limit freezing of underlying clay barriers (in cold climates) and protect the liner system from damage during construction and operation. TDA for this application is generally a maximum size of 3 inches.
Leachate recirculation trenches: TDA can be used as backfill around leachate recirculation trenches typically replacing conventional materials such as granular soil. Leachate recirculation trenches are used to reintroduce collected leachate back into the waste.
Gas collection trenches: TDA used in this application replaces granular soil as the bedding material for gas extraction pipes in the collection trenches. These trenches are usually located beyond the footprint of the landfill to control the lateral migration of landfill gas.
Gas collection layer: TDA layers provide good drainage and help protect clay and geomembrane liners in landfill gas collection systems.
Drainage layers in landfill covers: TDA can be used as a drainage layer in landfill covers. In this application, the TDA is typically enclosed in geotextile to decrease the amount of fines in the TDA layer and maintain TDA’s high permeability.
Cover system: TDA can be used as daily and intermediate cover material typically in a 50/50 mix of TDA and soil. Some applications also specify TDA size be no larger than 4 inches by 10 inches in size.

5. Building Foundations