SECTION 207: SUBGRADE PREPARATION
207.1 Description
This Work consists of compacti ng and finishing the Subgrade.
207.2 MATERIALS—Reserved
207.3 Construction Requirements
Maximum dry density of all soil types encountered or used will be determined in accordance with AASHTO T 180 (Modified Proctor), Method A or D (TTCP Modified). The Contractor shall ensure the top two (2) feet of borrow Mate rials in the finished Subgrade is comprised of Materia l with the design R-value. The Contractor shall compact the top six (6) inches of the Road bed to 95% of maximum density. The Contractor shall ensure the soil moisture content (at the t ime of compaction) is from optimum to optimum minus five percent (5%). For soils with a P I of 15 or greater, the Contractor shall ensure the moisture content of the soil at the time of compaction is from optimum moisture to optimum moisture plus four percent (4%). Field density tests shall be performed in accordance with AASH TO T310 or by other Department approved methods and S ection 906, “Minimum Testing R equirements.”
207.3.1 Tolerances
The Contractor shall ensure the top surface of the finished Sub grade along centerline shall not vary by more than 0.1 foot above or below established grade and 0.05 foot above or below the typical cross-section measured on the finished surfac e at right angles to the centerline. The Contractor sha ll correct all deviations from t hese tolerances.
207.4 Method of Measurement
The Department will measure Subgrade preparation using the dime nsions shown in the Contract and/or approved modifications. 207.5 BASIS OF PAYMENT Pay Item Pay Unit Subgrade Preparation Square Yard
207.5.1 Work Included in Payment
The Department will consider the item(s) listed in this sectio n as included in the pay items(s) listed in Section 207.5 , “Basis of Payment” and will n ot measure or pay for them separately: 1. No payment will be made for rehandling or reworking Material to meet moisture and density requirements; and 2. Proof rolling for Unstable Subgrade Stabilization shall be c onsidered Incidental to the Contract and will not be measured or paid for separately. Section 209: Blading and Reshaping Page 120