Engineering Solutions

Lightweight aggregate in North Carolina's longest bridge
Many architects, engineers and contractors recognize the advantages of Expanded Shale, as evidenced by the many impressive lightweight concrete structures found today throughout the world.

Concrete
Expanded Shale has been used for nearly 100 years primarily as a building material.  It is added to concrete to make buildings and bridges lighter since it is half the weight of standard crushed stone.

Expanded Shale is also used to improve the durability and service life of concrete by reducing chemical and drying shrinkage.  Adding pre-wetted Expanded Shale to conventional concrete mixture provides reservoirs of water within the concrete that slowly release the water after the concrete sets to provide internal curing to the mixture. Read more about Better Pavements Through Internal Hydration

The ASTM is currently developing a standard for internal curing using lightweight aggregates. The proposed new standard will be useful in a variety of civil engineering projects including roads, driveways, bridges and parking lots. Click here for details.

Lightweight, Insulative & Free Draining Fill
Compacted fills using Expanded Shale are approximately half the weight of fills using common materials. The load reduction, coupled with the high internal friction angle of the lightweight aggregate can reduce vertical and lateral forces by more than one-half.  Expanded Shale is also highly insulative.  Its uses can include:
  • Fill over poor soil, marshlands and shallow foundations
  • Enveloping underground conduits & pipelines for insulation or when in unstable soil conditions
  • Landfill leachate drainage systems
  • Landscaping and elevated plaza fills                                                                
  • Rooftop gardens
  • Structural repairs and rehabilitation
A valuable use for Expanded Shale in the Okanagan is in retaining walls.Expanded Shale is excellent to use as backfill for retaining walls because it is lightweight and free-draining.  Since water always takes the fastest exit, having two feet of Expanded Shale on the inside of a retaining wall will encourage water to drain through the rock rather than through the retaining wall which can cause staining and additional pressure on the wall.

LEED Credits
Expanded shale is an environmentally friendly, lightweight, porous product. It supports sustainable development and contributes to LEED certification in design and construction particularly in landscaping, backfill and concrete.  The following LEED® credits are just some of the areas where Expanded Shale can contribute to achieving LEED® Green Building certification.
  • Sustainable Sites Credit 3 - Rehabilitate damaged sites where development is complicated by environmental contamination and to reduce pressure on undeveloped land.
  • Sustainable Sites Credit 5.1 - Conserve existing natural areas and restore damaged areas to provide habitat and promote biodiversity.
  • Sustainable Site Credit 6.2 - Limit disruption and pollution of natural water flows by managing stormwater runoff.
  • Sustainable Site Credit 7.1 - Reduce heat islands (thermal gradient differences between developed and undeveloped areas) to minimize impact on microclimates and human and wildlife habitats.