310.04 Subgrade
190 If the available lime index for quick lime or hydrated lime falls below 90 percent, the Department will reduce the payment by 1 percent of the lime contract unit price for each 1 percent from 90 percent to 80 percent. If the available lime index falls below 80 percent, the Department will not pay for the additional lime necessary to bring the available lime index to 90 percent. The Department will consider the cost of excavating layers deeper that 8 in to be included in the contract unit price for the relevant subgrade modification or stabilization pa y item. The Department will consider the cost of water and rolling to be included in the contract unit price for the relevant subgrade treatment pay item. The Department will pay for Prime Coat in accordance with Section 408, "Prime Coat." The Department will consider the cost of chemical additives, at the specified rate for the appropriate soil classification in accordance with OHD L-51, to be included in the contract unit price for Modified Subgrade . The Department will consi der the cost of chemical additives, at the rate specified for the appropriate soil classification in accordance with OHD L-50, to be included in the contract unit price for Stabilized Subgrade . If a separate pay item for Selective Subgrade Topping exists, the Department will consider the cost of cementitious and lime additives to be included in the contract unit price for Cementitious Stabilized Subgrade, Cementitious Modified Subgrade, Lime Stabilized Subgrade, or Lime Modified Subgrade. SUBGRA DE
310.01 Description
This work consists of preparing the existing materials for the immediate construction of subbase, base, pavement, or surface.
310.02 Materials — Vacant
310.03 Equipment — Vacant
310.04 Construction Me Thods
A.Subgrade Method A for Traffic -Bound Surface Course Shape and crown the width of the existing roadbed with a blade grader to the grade shown on the Plans. Complete the cross section to at least a 2 percent crown or as directed by the Resident Engi neer. SUBGRADE 310.06 Remove unstable soil and exposed rocks larger than 3 in [75 mm], and replace with acceptable material. Finish each subgrade layer to a smooth, uniform surface and maintain this condition until placement of the succeeding layer.
B.Subgrade Method B for All Other Subbases, Bases, Pavement, or Surface Scarify or process the subgrade to create uniform moisture to a depth of 8 in [200 mm]. Shape the subgrade with material in accordance with Subsection 202.02.B, “Sel ective Subgrade Topping ,” or as directed by the Resident Engineer in rock cuts that cannot be scarified or otherwise processed. Pulverize the loosened soil and compact the top 8 in [200 mm] uniformly to a maximum density of at least 95 percent in accordanc e with Subsection 202.04.A(5), “Compaction of Fill.” Provide subgrade material with moisture content within 2 percentage points of optimum, in accordance with AASHTO T 99 unless approved by the Resident Engineer. Use mechanical tampers to compact sections of the subgrade inaccessible to rolling equipment. Finish the subgrade in accordance with Subsection 301.04.A, "Tolerances." Test the subgrade to ensure it meets the Contrac t and correct deficiencies before placing the succeeding course. Excavate unstable material below the top 12 in [300 mm] of the subgrade and backfill with acceptable material to the subgrade elevation in accordance with Subsection 202.04, “Construction Methods,” and as approved by the Resident Engineer. Remove and replace unstable material in fill areas at no additional cost to the Department. Correct or remove and aerate unstable material due to excess moisture in the top 12 in [300 mm] of the subgrade at no additional cost to the Department.
310.05 Method of Measuremen T — Vacant
310.06 Basis of Payment
The Department will pay for each pay item at the contract unit price per the specified pay unit as follows: Pay Item: Pay Unit:
A.SUBGRADE METHOD A Square Yard [Square Meter]
B.SUBGRADE METHOD B Square Yard [Square Meter] The Department will pay for this pay item once for work performed on the subgrade as defined in Subsection 101.02, “Definitions,” regardless of the work necessary to stabilize the subgrade as all subbases or base courses are placed on the subgrade. If excavation (beyond machine drifting) is necessary to complete the subgrade to the elevations shown on the Plans, the Department will pay for this work as the appropriate earthwork pay items in accordance with Section 202, “Earthwork.” The Department will pay for additional material needed to finish the subgrade to the elevatio ns shown on the Plans as the appropriate earthwork pay items in accordance with Section 202, “Earthwork.”
311.05 Processing Existing Base and Surface
192 SECTION 311 PROCESSING EXISTING BASE AND SURFACE
311.01 Description
This work consists of removing, processing, reusing, or disposing of existing aggregate surface course, base course, or asphalt surface.
311.02 Materials — Vacant
311.03 Equipment — Vacant
311.04 Construction Methods
Loosen or scarify the aggregate or other material to its full depth and width. Break aggregate or asphalt into pieces that will pass a 3 in [75 mm] sieve. Place the materials in windrows on the subgrade or shoulder. Avoid contamination of base or surface material due to exce ss soil or other foreign material. The Department will not pay for the costs of reworking damaged or contaminated material. Compact processed material used for base courses, shoulders, and drives in Method B, Method C, and Method D to at least 95 percent of maximum density in accordance with AASHTO T 99.
A.Method A —For Salvage and Stockpiling Prepare storage area by removing grass, weeds, and other waste before stockpiling material. Avoid the addition of excess amounts of soil or other foreign material, which would render it unusable. Load and haul the processed material to storage locations shown on the Plans.
B.Method B —For Use in Subgrade Place processed material in windrows on the shoulder during shaping and conditioning the subgrade. After complet ing the subgrade, spread the processed material uniformly over the width of the section and compact with the subgrade.
C.Method C —For Use as Subbase Spread the processed material evenly on the previously shaped, conditioned, and compacted subgrade and co mpact.
D.Method D —For Use in New Base Courses, Shoulders, or Drives Place the processed material on the completed subgrade as a base course, shoulder, or drive, or blend uniformly with new material for any course. Obtain approval by the Resident Engineer before using processed material.
311.05 Method of Measuremen T
The Resident Engineer will measure Processing Existing Base and Surface, Method A , Method B , Method C , and Method D along the centerline to the nearest foot [meter].
Source: Oklahoma Standard Specifications for Highway Construction, 2019 Edition. Pages 204–205 of 935.