ITEM 73 AGGREGATES 73.01 FINE AGGREGATE FOR CONCRETE
(a) Aggregate for under-drains shall be crushed stone, crushed slag, or washed gravel meeting the quality requirements of AASHTO, "Standard Specification for Crushed Stone, Crushed Slag, and Crushed Gravel for Open Graded Bituminous Road-Mix Surface Course," Serial Designation M 63, and the grading requirements for size 6, 7, or 8, Item 73.19.