Material Specifications

Proposed interim specifications for geotextile interlayer material

PropertyRequirementsTest Procedure
Geotextile TypeNonwoven, needle-punched, no thermal treatment to include calendaringEN 13249, Annex F (Certification)
ColorUniform/nominally same color fibers(Visual Inspection)
Mass per unit area

≥ 500 g/m² (14.7 oz/sq.yd)


≤ 550 g/m² (16.2 oz/sq.yd)


ISO 9864 (ASTM D 5261)
Thickness under load (pressure)

[a] At 2 kPa (0.29 psi): ≥ 3.0 mm (0.12 in.)


[b] At 20 kPa (2.9 psi): ≥ 2.5 mm (0.10 in.)


[c] At 200 kPa (29 psi): ≥ 1.0 mm (0.04 in.)


ISO 9863-1 (ASTM D 5199)
Wide-width tensile strength≥ 10 kN/m (685 lb/ft)ISO 10319 (ASTM D 4595)
Wide-width maximum elongation

≤ 130%


ISO 10319 (ASTM D 4595)
Water permeability in normal direction under load (pressure)≥ 1×10-4 m/s (3.3×10-4 ft/s) at 20 kPa (2.9 psi)DIN 60500-4 (modified ASTM D 5493)
In-plane water permeability (transmissivity) under load (pressure)

[a] ≥ 5×10-4 m/s (1.6×10-3 ft/s) at 20 kPa (2.9 psi)


[b] ≥2×10-4 m/s (6.6×10-4 ft/s) at 200 kPa (2.9 psi)


ISO 12958 (modified ASTM D 4716)
Weather resistanceRetained Strength ≥ 60%EN 12224 (ASTM D 4355 @ 500 hrs. exposure for grey, white, or black material only)
Alkali resistance≥ 96% Polypropylene/PolyethyleneEN 13249, Annex B (Certification)