801— Aggregate Underdrains

800-1 Division 800

INCIDENTAL CONSTRUCTION 801.1 Description 1 Construct aggregate underdrains using granular filter materials . 801.2 Materials 801.2.1 Coarse Aggregate 1 Use crushed stone, gravel, or slag that meet s the gradation requirements of Coarse Aggregate No. 57 as provided in the Appendix . Do not use slag with more than 60% abrasion loss when tested according to AASHTO T 96 . Use aggregate obtained from sources listed on Qualified Product s List 2 . 801.2.2 Geotextile 1 Provide an engineered fabric capable of reducing soil erosion. Use fabrics appearing on Qualified Products List 44. Submit the manufacturer’s literature on the proposed product and proof of satisfactory performance to the RCE before use. 2 Provide geotextiles that conform to the physical requirements in the following tables. Strength Property Requirements (All Fabrics) Property Class 1 Fabric Protected* Class 2 Fabric Unprotected Grab Strength ASTM D4632 90 lb 200 lb Seam Strength ** ASTM D4632 80 lb 180 lb Puncture Strength ASTM D4833 40 lb 80 lb CBR Puncture ASTM D6241 225 psi 475 psi Trapezoid Tear Strength ASTM D4533 40 lb 80 lb Elongation at Failure ASTM D4632 15% minimum 15% minimum Ultraviolet Degradation at 500 Hours ASTM D4355 50% Strength Retained 50% Strength Retained * Fabric is protected when cushioned from rock placement by a sufficient layer of sand or gravel at least 6 in. thick or by zero height of placement. All other conditions are unprotected. **Values apply to both field and manufactured seams. Sew seams upwards for inspection.