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304.03 Placing The maximum compacted thickness of any base or subbase course layer
shall not exceed 12 inches unless the Contractor demonstrates b y a test section that the required compaction can be obtained. If compacted layers more than 12 inches are allowed, the Contractor shall agree to make the necessary excavations an d backfilling in the course for the Resident to determine the density. When layers are constructed of differently graded aggregate, f ine grading of the lower layer will not be required except when millings are place d as the upper most layer. In this case the coarse graded base layer shall be fine graded to +/- ¾ inch and compacted to the required specification prior to placing the layer of millin gs. The layer of millings shall then be placed, shaped, and compacted within the tolerances spe cified below. Each layer of aggregate shall be placed over the full width of the section except, the Resident may authorize the Contractor to place less than full w idth layers, when existing traffic or other conditions restrict operations over the full w idth of the section. When the Contractor places material to complete the full width, the expo sed edge of the previously placed aggregate shall be cleaned of all contamination before a dditional base or subbase aggregate is placed adjacent to it. Aggregate base and subbase courses may be placed upon frozen s urfaces when such surfaces have been properly constructed. The material as spread shall be well mixed with no pockets of either fine or coarse material. Segregation of large or fine particles will not be a llowed.
304.04 Shaping, Compacting and Stabilizing Compaction of each layer of base and
subbase shall continue until a density of not less than 95% of the maximum density has been achieved for the full width and depth of the layer. The maximu m density shall be determined in accordance with AASHTO T180, Method C or D, corre cting for oversize particles except mixtures may have 40 percent or less retained on the ¾ inch sieve. Field density tests will be performed by the Department in accordance with AASHTO T 310. Compaction of each layer of base or subbase material that excee ds 40 percent retained on the ¾ inch sieve shall continue until a density of not less than 98% of the maximum density has been achieved for the full width and depth of the l ayer. Density tests and the maximum density determined by a field proctor shall be performe d by the Department. The surface, compaction and stability, shall be satisfacto rily maintained until the pavement course has been placed. If required, additional water and fine material shall be applied to prevent checking, raveling or rutting. If the top of any layer becomes contaminated by degradation of the aggregate or addition of foreign material, the contaminated material shall b e removed and replaced with the specified material. 3-3 All layers of base and subbase course shall be compacted to th e required density immediately after placing. As soon as the compaction of any la yer has been completed, the next layer shall be placed unless otherwise authorized. The Contractor shall bear full responsibility for and make all necessary repairs to the subbase course and the subgrade until the full depth of the sub base course is placed and compacted. Repairs shall be considered incidental to other con tract items. The top of any base or subbase course layer shall be scarified and loosened for a minimum depth of 1 inch immediat ely prior to the placing of the next layer of aggregate base or subbase. This scarifying shall be considered incidenta l to placing the course, and no separate payment will be made. The surface of each layer shall be maintained during compactio n operations in such a manner that a uniform texture is produced and the aggregate fir mly keyed. The moisture content of the material shall be maintained at the proper perce nt to attain the required compaction and stability. If voids remain on the surface after the subbase course has be en constructed to grade, compacted, checked and approved, sand-leveling material shall b e dumped and spread as directed. The quantity of sand leveling material shall be limi ted to the amount necessary to fill the voids and the minor low areas on the subbase surface. After the sand leveling material has been spread, it shall be completely rolled by a ru bber-tired roller with water applied, if necessary. The surface of this material shall be m aintained in its compacted and graded condition until the hot mix asphalt pavement has been pl aced. The furnishing, spreading, compacting and maintaining of sand leveling material will be considered included in the measurement and payment of the subbase course a nd no separate payment will be made. If the Contractor wishes to route public traffic over the compl eted Aggregate Base-Type A and B or Aggregate Subbase Course for a period of time greate r than 48 hours, the Aggregate Base and Aggregate Subbase Course shall be constructe d with a minimum 2″ surcharge above the design grade. Surcharge shall be constructe d with material meeting the requirements of Section 703.06(b), Subbase Aggregate-Type D. Wh enever the surcharge is used, it shall be placed on all the Aggregate Base and Aggregat e Subbase Course subjected to public traffic. When the surcharge is removed, it may be pla ced in driveways, sidewalks, approach roads, or the outer portions of the shoulders. Removal of the surcharge shall be followed immediately in successi on by the fine grading of the a ggregate base or subbase and construction of the HMA base layer. As per subsection 203.041 S alvage of Existing Hot Mix Asphalt Pavement, Recycled Asphalt Pavement (RAP) may be us ed as the top 3″ of aggregate. If RAP is utilized as the top 3″, a surcharge is not required. The furnishing, placing, maintaining, and removal of the surcha rge will not be paid for directly, but will be considered incidental to the Aggregate Ba se or Aggregate Subbase course pay item. 3-4
304.05 Surface Tolerance The completed surface of the subbase or base course shall
be shaped and maintained to a tolerance, above or below the req uired cross sectional shape, of ⅜ inch.
304.06 Method of Measurement Except as otherwise provided, ba se course subbase
course to the level of subgrade will be measured by the cubic y ard in place unless designated by pay item to be measured by truck measure. When m easured in place, the width and thickness for measurement will be the width and thick ness of base or subbase as shown on the plans or as modifi ed. The length will be along th e centerline unless modified by other methods generally recognized as conforming to good eng ineering practice. All measurements will be in accordance with Section 108.1 - Measure ment of Quantities for Payment. When designated by pay item to be measured by truck m easure, the measurement will be made in vehicles at the point of delivery as shown on d elivery slips in accordance with Section 108.1.3 F - Delivery Slips. As an alternative to in-place measurement, the Contractor and the Resident may agree in writing that the quantities of base or subbase for pay ment will be that shown in the Schedule of Items. If such an agreement is reached, no further measuring and computing of quantities will be required and the quantity referred to herein will be final. Aggregate base course and aggregate subbase course designated by pay item to be measured in place and used for driveways and other locations di fficult to accurately measure in place, may be measured in vehi cles at 80% of the number of c ubic yards accepted and used, at the point of delivery as shown by "Delivery Slips" in accordance with Section 108.1.3 F. The quantity so measured shall not exceed 1,250 yd³ per contract, after shrinkage. Pit measured items will be measured by the cubic yard in its’ original position by ground modeling or other approved surveying methods. The final quantity will be the amount actually removed from the pit and used on the Project. Tailings, screenings, overburden, material used as other pay items, waste, and unauth orized use of the material will be deducted from the final quantity amount.
304.07 Basis of Payment The accepted quantities of base cours e and subbase course
of the type specified will be paid for at the respective contra ct unit price per cubic yard complete in place. When aggregate is required for slope blanket backfill, bedding under drainage structures and other foundations, it shall be paid for at twice the contract unit price for the respective aggregate base or subbase course item used. Payment for base and subbase courses shall be full compensatio n for purchasing material, stripping pits, excavating, crushing, screening, haul ing, placing, compacting and other necessary processes which are required to furnish accepta ble material under this item. 3-5 Water and/or fines added to material to aid compaction and sta bilization to prevent raveling and rutting shall be incidental to the work. The quantity for payment of base and subbase placed on rock su bgrade shall include only that material placed above the normal subgrade line. Furnishing and placing base and sub base backfill material betw een the rock and the normal subgrade line will not be paid for directly but shall be considered incidental to the work. Payment will be made under: P a y I t e m P a y U n i t
304.10 Aggregate Subbase Course-Gravel C u b i c Y a r d
304.103 Aggregate Subbase Course-Gravel, Truck Measure Cubic Yard 304.104 Aggregate Subbase Course-Gravel, Plan Quantity Cubic Yard
304.14 Aggregate Base Course - Type A Cubic Yard
304.15 Aggregate Base Course - Type B Cubic Yard
304.16 Aggregate Base Course - Type C Cubic Yard
SECTION 306 - RECLAIMED MATERIAL FOR STABILIZED BASE Reserved SECTION 307 FULL DEPTH RECYCLING (UNTREATED OR TREATED WITH EMULSIFIED ASPHALT STABILIZER)
307.01 Description This work shall consist of pulverizing a po rtion of the existing
roadway structure into a homogenous mass, adding an emulsified asphalt stabilizer (if required) to the depth of the pulve rized material specified in the contract, placing and compacting this material to the lines, grades, and dimensions s hown on the plans or established by the Resident. MATERIALS
307.02 Pulverized Material Pulverized material shall consist o f the existing asphalt
pavement layers and one inch or more as specified of the underl ying gravel, pulverized and blended into a homogenous mass. Pulverized material will be pr ocessed to 100% passing a 2 inch square mesh sieve. 307.021 New Aggregate and Additional Recycled Material New agg regate, if required by the contract, shall meet the requirements of Subsection 703. 10 - Aggregate for Untreated Surface Course and Leveling Course, Type A. Aggregate Subbase C ourse Gravel Type D processed to 100 percent passing a 2 inch square mesh sieve and meeting the requirements