Patent ID: 8171751

Claim:
A method of making a composite material having foamed glass aggregate in a structural material matrix, comprising the steps of: a) sizing a particulate vitreous precursor material to segregate vitreous particles; b) extracting vitreous particles characterized by a predetermined range of size and particle size distribution to yield a pelletizable precursor; c) pelletizing the pelletizable precursor with a foaming agent to yield a plurality of foamable vitreous pellets characterized by a dilatometric softening point; d) preheating the foamable vitreous pellets to a first temperature about 25 degrees Celsius below the dilatometric softening point; e) passing the preheated vitreous pellets through a high-temperature region to foam the pellets to yield a plurality of foamed vitreous bodies; f) cooling the foamed vitreous bodies at a first predetermined cooling rate of about 20 degrees Celsius per minute to a second predetermined temperature below the dilatometric softening point; and g) cooling the foamed pellets from the second predetermined temperature to a third predetermined temperature at a second predetermined cooling rate of about 40 degrees Celsius per minute to yield foamed glass bodies; wherein the high temperature region is at least about 1200° C.; and wherein the foamed pellets are characterized by a mean cell diameter of less than about 0.2 mm.