2111.01 DESCRIPTION.
Granular subbase shall consist of a uniform mixture of granular material placed on a subgrade, uniformly moistened, shaped, and compacted, all in accordance with the contract documents.

2111.02 MATERIAL.
Material used for granular subbase shall meet the requirements of Section 4121 for the class of material required, or when specified in the contract documents or directed by the Engineer, be recycled crushed Portland cement concrete pavement material of the specified gradation. This material shall be reclaimed from an Interstate or Primary roadbed under the jurisdiction of the Department. Recycled PCC pavement, meeting the specified gradation, obtained from other sources may be used for granular subbase with the approval of the Engineer.

2111.03 EQUIPMENT.
Equipment used shall meet requirements of Section 2001 and the following:

A. Compaction Equipment.
Article 2001.05, Paragraphs B, C, D, and F shall apply except other types of equipment may be used provided it is demonstrated that they will consistently produce the required compaction.

2111.04 PREPARATION OF SUBGRADE.
The preparation of subgrade for granular subbase shall be in accordance with Section 2109, Natural Subgrade, with the following modifications:

A. Secondary and Local Projects.
The cross section shall be checked with an accurate template extending at least halfway across the width of the subgrade. Deviations of more than 1 inch (25 mm) from the template shall be repaired. The subgrade shall be prepared to remove dips or humps from the general profile and, when preparation is completed, shall have a good riding surface.

When PCC pavement is to be placed on the subbase, the subgrade preparation requirements shall be the same as for Primary projects.

B. Interstate and Primary Projects, State Parks, and Institutions.
The elevation of the subgrade surface will be indicated by grade stakes. The surface of the subgrade shall be corrected in both profile and cross section to within 0.05 foot (15 mm) of the desired elevation as indicated by the grade stakes.

After final subgrade trimming, the subgrade surface shall be in an undisturbed condition. In areas where this condition does not exist, recompaction shall be in accordance with Section 2109.

2111.05 DELIVERY OF MATERIALS.
Trucks shall be operated off the subgrade except in the area of unloading.

A clean aggregate interface shall be maintained between the granular subbase material and the porous backfill of all longitudinal subdrains.

2111.06 CONSTRUCTION OF GRANULAR SUBBASE.
Granular subbase material shall be uniformly moist prior to, and during compaction. Subbase material shall be placed in accordance with the contract documents.

Granular subbase shall be compacted with a maximum of three passes of a self propelled, non-vibratory steel or pneumatic roller. The roller shall have a compactive effort of 150 to 200 pounds per lineal inch (2.7 to 3.5 kg/mm) of contact surface.

The placing and compaction procedures will be evaluated on an initial trial section approximately 500 feet (150 m) long. This evaluation is to assess the extent of material degradation, consolidation, and permeability.

The profile and cross section tolerances for granular subbase shall be +0 to -0.05 foot (+0 mm to - 15 mm).

At the Contractor's option, the subbase may be constructed to a general elevation higher than the required design elevation and cut back to design elevation. In this case, excess material removed may be salvaged. It may be processed as required and used for any purpose for which it can be approved under the specifications. The price paid for salvaged and reused material will be the contract unit price for the material as used. If the exposed portions of the subbase are damaged or disturbed, they shall be restored to an acceptable condition, at the expense of the Contractor, prior to any subsequent operation that will cover or conceal these portions of the subbase.

For sections of pavement more than 600 feet (180 m) long, the subbase shall be completed not less than 600 feet (180 m) in advance of the operation of placing the concrete. The granular subbase shall not be placed more than 2 months before the pavement is placed. The granular subbase may be placed in areas where the Engineer and the Contractor agree it is reasonable to expect pavement construction can be accomplished prior to winter shutdown. The trimming of the granular subbase shall be restricted to 1 mile (1.6 km) ahead of the paving operation when winter shutdown is eminent.

2111.07 MAINTENANCE OF COMPLETED GRANULAR SUBBASE.
Hauling equipment and other traffic shall not be operated on the granular subbase material.

2111.08 METHOD OF MEASUREMENT.
Granular subbase material furnished and placed in accepted portions of work will be measured in square yards (square meters) for the specified design thickness. The design thickness of the placed material will be verified by spot checks of the grade. The measured area will be based on plan dimensions for the finished surface but will exclude fillets.

2111.09 BASIS OF PAYMENT.
The Contractor will be paid the contract unit price per square yard (square meter) for each specified design thickness of granular subbase as measured above. The contract will have a separate item for Granular Subbase, Place Only, in square yards (m²), when the Contracting Authority is providing the material or if the material is available from mandatory crushing on the contract. The cost of crushing should be included in the Contractor's price for granular subbase if recycling is not required but the Contractor chooses to crush the pavement removed for granular subbase.

This payment shall be full compensation for furnishing all materials, water, preparation of subgrade, and for doing all work necessary to complete the granular subbase in compliance with the contract documents.

Excavation in excess of 3 inches (75 mm) for preparation of subgrade at locations other than structures or existing pavements will be paid for according to Article 2102.14, or, if no contract unit price is provided, Article 1109.03, B.

When adjustments to profile grades cannot be made, fill required for preparation of subgrade at locations other than structures or existing pavements will be paid for according to Article 2102.14, or, if no contract price is provided, Article 1109.03, B.

When grading of the subgrade is a part of the contract, additional payment will not be made for excavation or fill necessary for preparation of subgrade.