ITEM 202 – CRUSHED AGGREGATE BASE COURSE

202.1 Description

This item shall consist of furnishing, placing and compacting crushed gravel, crushed stone or crushed rock on a prepared subgrade/subbase in one or more layers in accordance with this Specification and lines, grades, thickness and typical cross-sections shown on the Plans, or as established by the Engineer.

202.2 Material Requirements

202.2.1 Crushed Aggregate

It shall consist of hard, durable particles of fragments of stone or gravel crushed to the size and of the quality requirements of this item.

It shall be clean and free from vegetable matters, lumps or balls of clay, and other deleterious substances. The material shall be of such nature that it can be compacted readily to form a firm, stable base.

The base material shall conform to the grading requirements of table 202.1, whichever is called for in the Bill of Quantities.

Table 202.1 – Grading Requirements

Sieve Designation		Mass percent Passing
Standard,mm	Alternate US Standard	Grading A	Grading B
37.5 25 19 12.5 4.75 0.425 0.075	1" - 1/2" 1" 3/4" 1/2" No. 4 No. 40 No. 200	100 - 60 - 85 - 35 - 55 8 - 25 2 - 14	100 - 60 - 90 35 - 65 10 - 30 5 - 15

The portion of the material passing the 0.075 mm (No. 200) sieve shall not be greater than 0.66 (two thirds) of the fraction passing the 0.425 mm (No. 40) sieve.

The portion of the material passing the 0.425 mm (No. 40) sieve shall have a liquid limit of not more than 25 and a plasticity index of not more than 6 as determined by AASHTO T 89 and T 90, respectively.

The course aggregate retained on a 2.00 mm (No. 10) sieve, shall have a mass percent of wear not exceeding 45 by the Los Angeles Abrasion Test as determined by AASHTO T 96, and not less than 50 mass percent shall have at least one (1) fractured face.

The material passing the 19 mm sieve shall have a minimum soaked CBR-value of 80% tested according to AASHTO T 193. The CBR-value shall be obtained at the maximum dry density determined according to AASHTO T 180, Method D.

If filler, in addition to that naturally present, is necessary for meeting the grading requirements or for satisfactory bonding, it shall be uniformly blended with the crushed base course material on the road or in a pugmill unless otherwise specified or approved. Filler shall be obtained from sources approved by the Engineer, free from hard lumps and not contain more than 15 percent of material retained on the 4.75 mm (No. 4) sieve.

202.3 Construction Requirements

Same as Subsections 201.3.1 through 201.3.5

202.4 Method of Measurement

Crushed Aggregate Base Course will be measured by the cubic meter (m3). The quantity to be paid for shall be the design volume compacted in-place as shown on the Plans, and accepted in the completed course. No allowance shall be given for materials placed outside the design limits shown on the cross-sections. Trial sections shall not be measured separately but shall be included in the quantity of crushed aggregate base course.

202.5 Basis of Payment

The accepted quantities, measured as prescribed in Section 202.4, shall be paid for at the contract unit price for Crushed Aggregate Base Course which price and payment shall be full compensation for furnishing and placing all materials, including all labor, equipment, tools and incidentals necessary to complete the work prescribed in this Item.

Payment will be made under:

Pay  Item Number	Description	Unit of Measurement
202	Crushed Aggregate Base Course	Cubic Meter