Retaining walls typically support soil backfills and are designed based on the material properties of the soil backfill.
Properties such as unit weight and cohesion of a soil in addition to the height of the soil backfill are important factors in determining the design characteristics of the retaining wall. Generally, materials having higher unit weight and larger overall height will require more robust structures to retain them due to the increase in the lateral forces applied to the structure by the soil.
TDA has advantages as an alternative to conventional soil backfill mainly because it is significantly lighter than soil and is free draining. Since the in-place unit weight of TDA typically ranges between 40 and 50 lbs./ft3 (approximately one-third of the unit weight of most soils), it is very effective in reducing the lateral forces applied to the wall.
Using TDA as a retaining wall backfill can result in wall designs that use less steel and/or concrete and require less excavation, which can result in significant cost savings over typical soil backfill retaining walls.
Driveways & Parking Pads
Existing lands can be made up of soft, muddy soil at low-lying grades. These properties need a stable foundation that can be trusted to hold up overlying structures. Using a lift of TDA placed directly on the existing grade creates a strong foundation and eliminates the risk of differential settlement or other failures.
The high permeability and thermal insulation properties of TDA help create a capillary break, so moisture can’t wick its way towards the surface (no more cracking or buckling during spring thaw!). In fact, TDA has about 8 times better thermal insulation than soil!