DRAINAGE BEADS
Polystyrene drainage heads having optimized shapes to provide increased specific gravity and void volume at a given bulk density. Expanded forms of such drainage beads may be used as a geosynthetic aggregate in pre-assembled drainage units. Such pre-assembled drainage units may be used as foundation drains, septic drainage fields, or for other applications.
1 - 27 . (canceled)
28 . An aggregate comprising a plurality of expanded polystyrene drainage beads, wherein at least some of the drainage beads comprise a central spine including a first side and a second side opposite the first side and a plurality of legs-extending from the central spine and defining a plurality of first channels between the first legs and a plurality of second channels between the second legs; and wherein the aggregate of expanded polystyrene drainage beads further comprise a specific gravity and a bulk density such that a ratio of specific gravity to bulk density is greater than 2.3.
29 . The aggregate of drainage beads of claim 28 , wherein the ratio of specific gravity to bulk density is greater than 2.4.
30 . The aggregate of drainage beads of claim 28 , wherein the ratio of specific gravity to bulk density is greater than 2.5.
31 . The aggregate of drainage beads of claim 28 , wherein the first channels are wider than the first legs.
32 . The aggregate of drainage beads of claim 28 , wherein the first side comprises at least three first legs.
33 . The aggregate of drainage beads of claim 32 , wherein the second side comprises at least three second legs.
34 . The aggregate of drainage beads of claim 28 , wherein the central spine defines a spine width extending between the plurality of first and second legs and wherein the plurality of first and second legs each define a leg length extending away from the central spine; wherein the ratio of the leg length to the spine width is greater than 0.75.
35 . The aggregate of drainage beads of claim 34 , wherein the plurality of first and second legs each define a leg width; wherein the ratio of the leg length to the leg width is greater than 1.35.
36 . The aggregate of drainage beads of claim 34 , wherein the plurality of first legs includes a central leg that is longer than the other first legs.
37 . The aggregate of drainage beads of claim 28 , further comprising a perforated sleeve enclosing the plurality of drainage beads.
38 . The aggregate of drainage beads of claim 37 , further comprising a pipe extending from a first end of the perforated sleeve to a second end of the perforated sleeve.
39 . The aggregate of drainage beads of claim 28 , wherein the central spine defines a spine width extending between the plurality of first and second legs and wherein the plurality of first and second legs each define a leg length extending away from the central spine; wherein the ratio of the leg length to spine width is greater than 2.
40 . The aggregate of drainage beads of claim 28 , wherein at least some of the drainage beads further comprise a first arm extending from a third side of the central spine and a second arm extending from a fourth side of the central spine.
41 . The aggregate of drainage beads of claim 40 , wherein the first and second arms extend in substantially perpendicular directions to the first and second legs.
42 . The aggregate of drainage beads of claim 28 , wherein the central spine and first and second legs are substantially planar.
43 . The aggregate of drainage beads of claim 28 , wherein the second channels are wider than the second legs.
44 . The aggregate of drainage beads of claim 33 , wherein the central spine defines a spine width extending between the at least three first and second legs; wherein the at least three first and second legs each define a leg length extending away from the central spine; and wherein the ratio of the leg length to spine width is greater than 0.8.
45 . The aggregate of drainage beads of claim 44 , wherein the at least three first and second legs each define a leg width; wherein the ratio of the leg length to leg width is greater than 1.4.
46 . An aggregate comprising a plurality of expanded polystyrene drainage beads, wherein at least some of the drainage beads comprise a central spine including a first side and a second side opposite the first side and a plurality of legs-extending from the central spine and defining a plurality of first channels between the first legs and a plurality of second channels between the second legs; and wherein the aggregate of expanded polystyrene drainage beads further comprise a specific gravity and a bulk density such that a ratio of specific gravity to bulk density is greater than 2.3 and less than 2.875.