Concrete and CMU producers are under growing pressure to cut unit weight, document recycled content, and hold the line on compressive strength — often all at the same time. Expanded glass granulate has emerged as one of the more practical answers to that combination of demands: a lightweight, closed-cell aggregate made from 100% post-consumer recycled glass, available in five grain sizes for a wide range of construction applications.
How Expanded Glass Granulate Is Manufactured
Production starts with a silica flour base, which is wet-processed into a raw “green grain.” That green grain is then dried and expanded in a rotary kiln under controlled conditions, producing a lightweight, closed-cell particle composed of amorphous silicon dioxide (SiO₂). It’s worth noting that expanded glass is not the same material as foam glass — while both start from a similar silica base, the kiln process used for expanded glass gives it tighter particle size control and better workability characteristics.
Technical Properties
- Composition: Amorphous silicon dioxide (SiO₂)
- Structure: Closed-cell, prevents capillary action
- Recycled content: 100% post-consumer waste glass
- Grain sizes: Five distinct sizes, fine through coarse
- Density: Significantly lower than natural sand or aggregate
- Pricing: By volume (cubic yard), not by weight
- Packaging: 1.2 cubic foot bags, 50 per pallet, with bulk super sacks available
Where Expanded Glass Granulate Is Used
The five available grain sizes let formulators dial in performance across a wide range of applications. In concrete and CMU block manufacturing, expanded glass granulate can replace up to 25% of sand by volume, reducing unit weight with minimal impact on compressive strength, while its rounded particles improve workability and reduce mixing time in dry mortar, tile adhesive, and grout systems. In lightweight concrete for elevated decks, it helps producers meet ASTM C330 unit weight requirements while still hitting target PSI.
GFRC and precast producers use it to cut component weight, which adds up to real shipping savings — more pallets per truck and easier job site handling. In ultra-high performance concrete (UHPC), it functions as an internal curing agent, managing water retention and helping control early-age cracking in low water-to-cementitious-material mixes. High temperature stability and chemical inertness also make it a fit for refractory and specialty industrial applications requiring lightweight fill and low thermal conductivity.
An Emerging Use: Fire Suppression
Expanded glass granulate has also proven effective in suppressing lithium-ion battery and other Class D fires. Glasphera testing has established encapsulation depths of two to six inches, an application area that’s growing quickly as EV infrastructure, data centers, and battery storage facilities expand across the country.
Why Choose Expanded Glass Over Traditional Aggregate?
Traditional aggregate extraction is resource-intensive, consuming an estimated 250 gallons of water per ton of processed material — an impact that’s rarely reflected in a published EPD. Expanded glass granulate diverts waste glass from landfills and reduces dependence on virgin aggregate extraction, while still delivering the performance metrics producers need: lower unit weight, improved workability, no capillary water absorption, and 100% recycled content for green building compliance.
Getting Started
Tech Silica holds exclusive U.S. distribution rights for Glasphera expanded glass granulate, with inventory maintained in Chicago, IL and Brooklyn, NY and a standard 45-day lead time. Full specifications and grain size details are available on our Expanded Glass Granulate product page. For finer applications like tile adhesive and GFRC, see our Expanded Glass Sand line.
Our team can help you select grain size and replacement rate for your specific mix design. Contact Tech Silica to request sample kits or a quote.