Answers for engineers, contractors and owners

Yes. Specifications place it above the water table or hold it down with cover material.^[4] Where the fill can flood, the design must anchor or ballast it, as at Jim Lorimer Park.^[9]

Over-compaction and vibration break particles down. Enviro-Rock is placed in 300 to 600 mm loose lifts under a static roller with no vibration, or in 150 to 300 mm loose lifts under a plate compactor with more passes rather than more vibration, and compacted 10 to 20%; jumping jacks are not used.^[10][11]

Enviro-Rock's water absorption is 7.2% uncompacted.^[7] Absorption of foam glass aggregate rises with soaking time, and Indiana DOT specifies 30 to 60% by weight after 28 days.^[12] Moisture also raises thermal conductivity, so insulation designs use in-service values.^[13]

New York and Indiana have published foam glass aggregate fill specifications, and Maine DOT has used a project special provision.^[14][12][15] In BC, Enviro-Rock is an accepted lightweight fill product on the Ministry of Transportation and Transit Recognized Products List.^[16]

It insulates, at a lower value per inch. In a Quebec field trial, a 150 mm foam glass aggregate layer insulated a pavement about as well as 50 mm of extruded polystyrene board in the first, mild winter.^[17]

Enviro-Rock is glass and does not burn.^[18] No fire test to a named standard, such as CAN/ULC-S114, has been published for it. A European Technical Assessment for a different cellular glass loose fill declares reaction-to-fire Class A1.^[19]

Material price, then haul distance. Illinois Tollway research found that shipping distance significantly affects the cost of foam glass aggregate: in its example, an 800-mile haul added about $34 to an in-place cubic yard costing $169.^[4] Because a load is limited by volume rather than weight, B-trains of up to 140 m³ spread that haul over more fill.^[20][8]