301Aggregate Subbase, Base Courses, and Bed Course Material

Aggregate Subbase, Base Courses, and Bed Course Material

301.1DESCRIPTION

1 This section describes the requirements for placing one or more courses of aggregate on a prepared surface.

301.2MATERIALS

1 Provide materials in accordance with the following:

Material Subsection Aggregate 803

301.3EQUIPMENT

1 Unless otherwise approved by the engineer, use a pugmill capable of thorough and consistent blending to mix aggregate and water for subbases and bases.

301.4CONSTRUCTION

301.4.1 Bed Course Material

1 Shape the bed course material to coincide with the bottom surface of the item or appurtenance to be constructed on the bed course material. Tamp or compact the bed course material into place. No density requirements will apply.

301.4.2 Subbases and Bases

301.4.2.1 General

1 At least 14 calendar days before placement, submit aggregate samples for determination of optimum moisture content, maximum density, and R-value. Obtain the samples in the engineer’s presence.

301.4.2.2 Lot and Sublot Sizes

301.4.2.2.1 Weight [Mass] Measurement

1 A lot is defined as the quantity of material represented by five tests or a maximum of 5000 ton [5000 t], and a sublot is the quantity of base or subbase represented by one test or a maximum of 1000 ton [1000 t].

Aggregate Subbase, Base Courses, and Bed Course Material SECTION 301

301.4.2.2.2 Volume Measurement

1 A lot is defined as the quantity of material represented by five tests or a maximum volume of 2500 yd3 [2000 m3], and a sublot is the quantity of base or subbase represented by one test or a maximum of 500 yd3 [400 m3].

301.4.2.2.3 Area Measurement

1 A lot is defined as the quantity of material represented by five tests or a maximum area as calculated by the following equation:

1.1Step 1. Determine the number of lots

Lots = Q 92,000 x th Where: Lots = Number of lots required Q = T otal quantity of base or subbase (yd2) th = Lift thickness (in)

1.2Step 2. Determine the lot size

Lot Size (yd2) = Q Lots Where: Lots = Number of lots required Q = T otal quantity of base or subbase (yd2)

Lot Size (m2) = 2,125,000 th Where: th = Lift thickness (mm)

2 A sublot is the quantity of base or subbase represented by one test or a maximum of one- fifth of the lot size.

301.4.2.3 Placing

1 During placement of material, the engineer will determine the Liquid Limit (LL) and Plasticity Index (PI) for all gradation samples. Remove from the roadway material exceeding the specified limits for these values in accordance with T able 803.4.4-2, Aggregate Properties, Subbase, and Base, and replace with material meeting the requirements.

2 Do not allow the compacted thickness of any one layer to exceed 8 in [200 mm].If the compacted depth of the base or subbase course exceeds 8 in [200 mm], construct the course in two or more layers of approximately equal thickness.

Aggregate Subbase, Base Courses, and Bed Course Material SECTION 301

3 Compact each layer to at least 95.0 percent of AASHTO T180 maximum density.

4 Compact material when moisture content is within plus 2 percent to minus 4 percent of optimum.

5 Add water, if necessary, during mixing and apply water over the materials during compaction as necessary to obtain optimum moisture content and maximum density.

301.4.3 Acceptance

1 Aggregate gradation for subbase and base material will be accepted in accordance with Subsection 113.1, Acceptance of Aggregate.

301.5MEASUREMENT and PAYMENT

301.5.1 General

1 The engineer will measure Pit Run Subbase, Crusher Run Subbase, Crushed Subbase, Subbase, Crushed Base, and Bed Course Material by the ton [metric ton], cubic yard [cubic meter], or square yard [square meter].

neat line for width, including one half the taper width where applicable, multiplied by the neat line for thickness, multiplied by the neat line for length of the completed surface.

width, including one half the taper width where applicable, multiplied by the neat line for length of the completed surface.

mixing, added to the material before the material is weighed, will not be deducted from the measurement unless it exceeds the maximum moisture content.

2 The department will pay as follows:

Pay Item

Pay Unit Measure to the Nearest Pay to the Nearest Bed Course Material ton, CY, SY [t, m3, m2] 0.05 ton, ft, ft [0.05 t, 0.5 m, 0.5m] 0.05 ton, CY, SY [0.05 t, m3, m2] Crushed Base ton, CY, SY [t, m3, m2] 0.05 ton, ft, ft [0.05 t, 0.5 m, 0.5m] 0.05 ton, CY, SY [0.05 t, m3, m2] Crushed Subbase ton, CY, SY [t, m3, m2] 0.05 ton, ft, ft [0.05 t, 0.5 m, 0.5m] 0.05 ton, CY, SY [0.05 t, m3, m2]

Aggregate Subbase, Base Courses, and Bed Course Material SECTION 301

Pay Item

Pay Unit Measure to the Nearest Pay to the Nearest Crusher Run Subbase ton, CY, SY [t, m3, m2] 0.05 ton, ft, ft [0.05 t, 0.5 m, 0.5m] 0.05 ton,CY, SY [0.05 t, m3, m2] Pit Run Subbase ton, CY, SY [t, m3, m2] 0.05 ton, ft, ft [0.05 t, 0.5 m, 0.5m] 0.05 ton, CY, SY [0.05 t, m3, m2] Subbase ton, CY, SY [t, m3, m2] 0.05 ton, ft, ft [0.05 t, 0.5 m, 0.5m] 0.05 ton, CY, SY [0.05 t, m3, m2]

301.5.2 Referenced Sections for Direct Payment

1 When specified, the engineer will measure and pay for:

209, Watering.

301.5.3 Determination of Pay Factor301.5.3 Determination of Pay Factor

1 The engineer will evaluate aggregate gradation tests for subbases and bases in accordance with Subsection 1 13.1, Acceptance of Aggregate, and will apply pay adjustments. The maximum pay factor per lot will be 1.00.

301.5.4 Pay Adjustments

1 The engineer will calculate pay adjustments for aggregate gradation for subbases and bases as follows:

Aggregate Gradation: PAA = CB x (PFA -1) × LSA

Where: PAA = Pay Adjustment for Aggregate Gradation ($$) CB = Unit Contract Price for the respective Aggregate Subbase, Base Course, and Bed Course Material pay item ($$) PF A = Aggregate Gradation Pay Factor for evaluated lot LSA = Lot Size for Aggregate Gradation evaluated lot (short ton [metric ton])