// Blog October 28, 2020

Thermal Conductivity Testing of Foam Glass Gravel

The thermal conductivity of a novel foam glass gravel (produced by Glavel Inc.) for building applications was tested with the C-Therm Trident Flex TPS Method.  

Building and construction applications often encompass a wide range of material types. Mechanical properties of these materials such as tensile strength, fatigue limit, and compression strength are of great importance from a structural perspective.  The thermal properties of the selected materials are also important to consider. A material’s thermal stability can be directly related to structural integrity when dealing with changes in seasonal temperature, while thermoregulatory properties can dictate energy efficiency ratings. The use of green materials that have attractive physical and thermal properties can reduce building carbon footprint. Materials that provide physical, thermal, and green advantages, while also being cost-effective, make for ideal candidates.

thermal building gravel

Installing Glavel Thermal Glass Foam Gravel

Glavel, Inc., based in Burlington VT,  is a company that specializes in the production of foam glass gravel, a high-performance aggregate used for a variety of building uses in the construction industry.  Foam glass gravel is produced almost entirely from post-consumer recycled glass and provides thermal insulation of R1.7 per compacted inch. It is extremely lightweight (10 pounds per cubic foot), but has high compressive strength for load-bearing applications. These attributes make it a great substitute for rigid foam board in sub-slab insulation while also being a good fit for a lightweight green roof fill, roadbeds, embankment stabilization, and tunnel fill. Being so lightweight, fuel consumption in transportation to job sites is reduced, plus the recycled content makes Glavel a naturally low-embodied carbon building material. Glavel foam glass will soon be produced in northern Vermont at a manufacturing facility that is powered fully by renewable energy, further reducing the carbon associated with the product. Manufacturing in Vermont is slated for summer 2021.

Flex TPS Thermal Conductivity Sensors

Flex TPS ISO 22007-2 Sensors

C-Therm characterized a Glavel Inc. foam glass sample using the Transient Plane Source (TPS) method on the Trident Platform. TPS is highly applicable for testing porous samples and is recommended for a variety of building materials such as cement and concrete. The ability to test without the use of a contact agent makes TPS an excellent option for this material type. Testing was performed under ambient conditions in accordance with ISO 22007-2.

Thermal Conductivity Testing of Foam Glass

Testing Thermal Conductivity of Glavel Foam Glass Gravel

The sample was tested in triplicate using a 13 mm TPS sensor via the TPS Bulk Utility. For testing of this material, a 500g weight was placed on top of the setup to apply adequate contact force between sample and sensor as shown above.

The thermal conductivity of the individual tests, as well as the average value and % RSD (Relative Standard deviation), are reported below. All measurements were validated in accordance with the ISO 22007-2 requirements.

Sample ID Test Number Thermal Conductivity (W/mK) Average (W/mK) RSD (%)
Glavel Foam Glass 1 0.0735 0.0748 1.8%
2 0.0762
3 0.0746

Results showed good reproducibility between measurements with an overall %RSD less than 2%. The average thermal conductivity of 0.0748 W/mK indicates good insulative properties and highly applicable for the intended end-use application.

To learn more about testing thermal conductivity with Trident, visit www.ctherm.com/products/trident 

To learn more about Glavel glass foam gravel, visit https://www.glavel.com 


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