Enviro-Rock for geotechnical engineers

Enviro-Rock's published value is 39° at 65 kPa.^[1] Measured friction angles for foam glass aggregate fall as normal stress rises, so design values are chosen for the expected stress level^[3] and confirmed by the geotechnical engineer from test data and design conditions.^[2]

Treat the fill as buoyant. Specifications place foam glass aggregate above the water table or hold it down with cover material^[3], and at Jim Lorimer Park, where the site floods seasonally, the design anchored the fill against uplift.^[8]

Heavy effort does: in lab tests summarized by FHWA, a modified Proctor at half energy raised foam glass aggregate density 2.4 to 2.7 times.^[12] Enviro-Rock is placed in 300 to 600 mm loose lifts under a static roller with no vibration, or 150 to 300 mm loose lifts under a plate compactor with more passes rather than more vibration, and compacted 10 to 20%.^[5][6]

Enviro-Rock's water absorption is 7.2% uncompacted, and closed internal cells limit water penetration while the spaces between particles drain.^[1][13] In service, foam glass aggregate holds some water: a Norwegian road study measured about 20% moisture by weight, so check unit weight and thermal values for moist conditions.^[14]

Illinois Tollway design guidance projects less than 0.1% creep over 50 years for foam glass aggregate under sustained stresses up to about 96 kPa (2,000 psf).^[3] Enviro-Rock has not published creep test data of its own.

In BC, it is listed as an accepted product under Lightweight Fill Material on the Ministry's Recognized Products List.^[9] Alberta lists it as a Potential Product and has no experience with it yet.^[15][16] It has no approval in Washington, Oregon, California, Alaska or the Yukon, where acceptance rests with the project owner and the engineer of record.