301.01 Description
This work is producing and placing one or more courses of aggregate surfacing on a prepared surface or producing and stockpiling aggregate surfacing.
301.02 Materials
301.02.1 Aggregates
Obtain aggregates from sources meeting Section 106 requirements to produce material in accordance with Subsection 701.02.1 and the following subsection requirements: Crushed Base Course .................................. 701.02.4 and 701.02.5 Crushed Cover Aggregate ............................ 701.02.8 Crushed Top Surfacing ................................ 701.02.6 and 701.02.7 Sand Surfacing............................................. 701.02.3 Selected Surfacing ....................................... 701.02.2 Furnish bridge end backfill in accordance with Subsection 701.13.
301.02.2 Aggregate Treatment
Choose the material that will be used to treat the aggregate, which may include MC-70, or calcium or magnesium chloride. Furnish liquid magnesium or calcium chloride in accordance with Subsection 713.03 requirements. Furnish liquid asphalt in accordance with Section 702 requirements. If used, furnish MC-70 listed on the QPL. Blotter material is material with 100% passing the ½-inch (12.5 mm) screen and having a PI of 6 or less.
301.02.3 Optional Recycled Material
RAP or Recycled Concrete Aggregate (RCA) may be blended with existing crushed aggregate course, additional aggregate course, or a combination of these. Ensure blended material meets the requirements of Subsections 701.02.1 and 701.02.4.
1.Pugmill recycled products with existing or virgin aggregates to produce a uniform mixture.
2.Blend no more than 40% RAP or 50% RCA by weight with existing or virgin aggregates.
3.Total recycled mixtures may not exceed 50% by weight of the blended base course.
4.Use weighing or metering devices to control the recycled material introduced into the mix within the specified limits.
301.03 Construction Requirements
301.03.1 Sampling, Testing, and Acceptance
A.Production Control. Develop a quality control sampling and testing plan for production and be responsible for all sampling and testing for gradation and fracture control during aggregate production.
B.Acceptance Sampling and Testing. The Project Manager will randomly select samples taken by the Contractor and witnessed by an Inspector, for gradation and fracture testing from processed material in its final position on the roadway in accordance with MT 201 . Samples for other tests will be taken at the point of production. The following acceptance tests are used: Gradation ..................................................... MT 202 301 – AGGREGATE SURFACING 2020 EDITION V5.1 301-2 Fracture ....................................................... AASHTO T 335 The quantity represented by 5 samples is a lot when production schedules and material continuity permit. The Project Manager may establish a lot consisting of a quantity represented by 3 to 7 consecutive random samples when there are short production runs, significant material changes, or other unusual characteristics of the work.
C.Acceptance. Surfacing aggregates are evaluated for gradation and fracture on a lot-by- lot basis. The upper and lower limits in the gradation tables in Section 701 are the upper and lower limits in the evaluation formulas. The specified minimum fracture is the lower limit. Acceptance is made in accordance with Subsection 105.03.2.
301.03.2 Equipment
A.Rollers. Use rollers in accordance with Subsection 210.03.4.
B.Watering Equipment. Use watering equipment in accordance with Subsection 210.03.5.
C.Scales. Furnish scales in accordance with Subsection 109.01.1 or use certified permanently installed commercial scales. Furnish and have readily available at least 10 50-pound (22.7 kg) weights for testing Contractor furnished scales. Furnish housing for the scale recording devices. Scale accuracy must be ½ of 1% at any weight. Alternative weigh methods or devices may be acceptable if they produce the required accuracy. Platform and belt-conveyor scale requirements are as follows:
1.Platform Scales. Use platform scales having the length to weigh an entire vehicle in an unbroken operation. Truck-trailer combinations may be weighed separately if the scale approaches are:
a.Compacted gravel or asphalt.
b.Long enough and level with the scale platform to accommodate the entire truck- trailer units; and
c.Continually maintained. Release all brakes as the unit is weighed.
2.Belt-conveyor Scales. Belt-conveyor scales may be used for non-asphaltic materials when meeting the requirements of Subsection 109.01.1 and the following:
a.The scale meets the National Bureau of Standards requirements for belt-conveyor scales, except as modified below.
b.A daily static-load test is made after approximately ½ hour of continuous belt conveyor operation and whenever the air temperature varies 15 °F (9 °C) or more. Have a calibration test performed once daily and whenever the daily static-load test shows adjustments are required.
c.Make calibration computations, calibration procedures and results, and related documents available for the Project Manager’s review. Clearly mark test chains with calibration constants. Carry test chains and test weights in protective containers and make immediately available for belt-conveyor scale testing.
d.Perform accuracy checks by checking the average of 5 or more sequential payloads of hauling units on approved platform scales. The acceptable accuracy is ± 0.5% of the payload of the average hauling unit. If the recording odometer of the belt-conveyor scales in use is graduated to 0.1-ton (91 kg) increments and is 2020 EDITION V5.1 AGGREGATE SURFACING – 301 301-3 a cumulative recording process, differences in readings and variations less than 0.1-ton (91 kg) may carry over from one hauling unit to another. Conveyor weight conformation is based on the tonnage obtained from readings taken from the sealed odometer at the beginning and end of each check period. The number of check loads will be increased should the test results fluctuate. Furnish a lock to secure the recording tape, odometer, totalizer, calibration adjustment, and clock-time imprinter. The Project Manager will lock the equipment and retain the keys before materials are delivered to the roadway.
301.03.3 Reject
Dispose of reject material produced from Department sources as directed.
301.03.4 Crushed Aggregate Course
When crushed aggregate course is a bid item, construct the aggregate surfacing section to the specified typical cross section and profile grade. Select one of the following two options to construct the aggregate section:
1.Full depth crushed base course.
2.Top 0.15 foot (45 mm) crushed top surfacing; remaining depth crushed base course. Indicate the selected option and the grade of crushed base course (Type “A” grade 5, Type “A” grade 6, or Type “A” grade 7) before beginning aggregate production. Only one grade of crushed base course will be permitted. If option 2 is selected use Type “A” grade 2 crushed top surfacing. Quality assurance lot sizes, test intervals and material tolerances will be based upon the materials selected.
A.Optional Blended Base Course. Blending RAP or Recycled Concrete Aggregate with existing crushed aggregate course, additional aggregate course, or a combination of these. Produced aggregate must meet the requirements of Subsections 701.02.1 and
701.02 4.
1.Recycled products must be pugmilled with existing or virgin aggregates to produce a uniform mixture.
2.Blend no more than 40% RAP or 50% concrete by weight with existing or virgin aggregates.
3.Total recycled mixtures may not exceed 50% by weight of the blended base course.
4.Use weighing or metering devices to control the recycled material introduced into the mix within the specified limits.
5.Meet the compaction requirements of Subsection 301.03.5.
301.03.5 Aggregate Surfacing Construction
A.Surface Preparation. Do not place aggregate surfacing material on any of the following:
1.Any surface not meeting the dry density requirements for that surface.
2.A rutted or frozen subgrade or aggregate surface; or
3.Any surface not meeting grade or surface smoothness specifications.
4.Unstable or pumping material is unacceptable. Rework or remove and replace the material prior to placing additional lifts or materials.
B.Pugmill Mixing. Pugmill mix all surfacing aggregates except crushed cover aggregate. 301 – AGGREGATE SURFACING 2020 EDITION V5.1 301-4 Uniformly mix aggregate surfacing and water in a central plant pugmill mixer. Proportion all blending material, filler, and binder by weight to within ± 1∕2 of 1% of the specified quantity before mixing. Add the water needed to reach the specified density. Additional water may be added only once to the aggregate surfacing once it’s placed on the roadway to replace moisture lost to surface evaporation. If additional water is needed, pick up the mixture and remix it in the pugmill. After pugmilling, transport, place, and spread aggregate surfacing on the roadway. Spread in maximum 8-inch (200 mm) compacted layers to the required grade and typical section. Spot fill low areas by scarifying roadway, spreading aggregate, and compacting to specified density.
C.Road Mixing. When specified, place, mix and spread the surfacing aggregates on approved surfaces at optimum moisture using motor graders or other approved equipment. Water may be added to the aggregate to reach optimum moisture during or after crushing. Once uniformly mixed, spread in maximum 8-inch (200 mm) compacted layers to the required grade and typical cross section. Roller compact the spread layer. Correct or remove equipment from the work failing to maintain uniform gradation of the material for the entire width and thickness of the roadway.
D.Compaction. Compact aggregate surfacing to 98% of the target density. The initial target density is the average of the maximum density of at least 2 tests on samples representing the material to be compacted. Maximum density is determined in accordance with MT 230 . The Project Manager may take samples from the materials placed on the roadway. They will be tested, and the results averaged to determine a new target density for the material remaining to be placed. The Project Manager will establish a target density for each course, grade, and type of surfacing aggregate. A new target density will be established if the aggregate characteristics change. The Department will test the lift(s) of surfacing aggregate in 2,000-foot long (610 m) sections based on full typical section width. The in-place dry density of each lift is determined within each section at 10 randomly selected locations. The average of the 10 tests must be a minimum of 98% of the target with not more than 2 out of 10 tests being less than 98% of the target. The number of tests will be pro-rated for sections with partial lengths and widths. In pro-rated sections, the average of the tests must be a minimum of 98% of target density. Be responsible for controlling compaction and all necessary control testing. Notify the Project Manager once compaction is complete on a section so it may be tested. Re-compact sections not meeting density requirements. Re-compacted sections will be tested at 10 new random locations. Compaction and testing will continue until the section meets density requirements. Densities will be determined in accordance with MT 212, MT 218, and MT 230 . 2020 EDITION V5.1 AGGREGATE SURFACING – 301 301-5
E.Finishing. Finish each course of compacted aggregate surfacing to the specified grade and section. The final lift will be accepted in accordance with Subsection 105.08. Use trimmings on the in-slopes, on sections of uncompleted roadway or return to the pit area. When quantities are measured by the ton (MT), excess material returned to the pit is deducted from the pay quantities.
F.Curing. Allow the final lift of crushed aggregate course to cure. The aggregate must meet both requirements: • Cure for a minimum of 72 hours, and • Until the in-place moisture content is 2% or more below optimum moisture content or a maximum of 5% final moisture content, whichever is lower. Meet these requirements prior to aggregate treatment or paving. Notify the Project Manager when a section is complete and ready for Department testing. The in-place soil moisture content will be determined on the final lift of surfacing aggregate in 2,000-foot (610 m) long sections. Moisture content will be tested within each section at 10 random locations. Not more than 1 test may be above the target value. The number of tests will be prorated for sections with partial lengths. Additional tests may be taken at the Project Manager’s discretion. The Contractor is responsible for corrective actions on sections not meeting moisture content requirements. After corrective actions have been taken, the sections will be tested at 10 random locations or prorated as determined by the Project Manager.
G.Restrictions. The Project Manager may restrict equipment speed and load weights to prevent damage to existing and new work, public thoroughfares, or safety. Unstable or pumping material is unacceptable. Rework or remove and replace the material prior to placing additional lifts or materials.
H.Surface Smoothness. Finish the aggregate surface to the specified grade within Table 301-1 tolerances. TABLE 301-1 SURFACE SMOOTHNESS Aggregate Size Tolerance Distance 1½-inch (40 mm) and larger +0.08-foot (24 mm) to -0.05-foot (15 mm) 30 feet (9.2 m) Less than 1½-inch (40 mm) ±0.04-foot (12 mm) 60 feet (18.4 m)
301.03.6 Shoulder Gravel
Compact shoulder gravel to provide a firm, hard surface. Finish the slope to provide a smooth surface from the edge of pavement to the catch point. Furnish gravel in accordance with Table 301-2 gradation requirements. 301 – AGGREGATE SURFACING 2020 EDITION V5.1 301-6 TABLE 301-2 SHOULDER GRAVEL GRADATION REQUIREMENTS Percentage By Weight Passing Square Mesh Sieves Sieve Size Percent Passing ¾-inch (19.0 mm) 100 No. 4 (4.75 mm) 25-85 No. 200 (0.075 mm) 5-20 Cold milled pavement is not required to meet the above gradation when used as shoulder gravel.
301.03.7 Traffic Gravel
Furnish traffic gravel in accordance with Subsections 701.02.4 or 701.02.6. Traffic gravel is not evaluated in accordance with Subsection 105.03.2. Place traffic gravel in the locations and quantities directed by the Project Manager. Milled and/or pulverized plant mix material may be used as traffic gravel in accordance with the following conditions:
1.Submit in writing a detailed plan showing locations for the use of the milled or pulverized material. Include an updated traffic control plan and stockpile locations.
2.Place all milled/pulverized material below the finished subgrade elevation unless approved in writing by the Project Manager.
3.Do not mill/pulverize areas outside the planned limits unless approved in writing by the Project Manager.
4.100% of the milled/pulverized material must pass the 2-inch (50 mm) sieve.
301.03.8 Aggregate Treatment
Furnish and apply aggregate treatment on aggregate surfaces. Submit the material(s) and application rates to be used for aggregate treatment. The material must bond with the aggregate and the treated surface must be durable under vehicular traffic. Apply aggregate treatment material and necessary blotter according to the manufacturer’s recommendations.
301.03.9 Bridge End Backfill
Place bridge end backfill full width of the roadway embankment typical section to 10 feet (3.0
m.behind the base of the pile cap then ascending on a 6H:1V slope. The top of the bridge end backfill is subgrade elevation. When the bridge end backfill does not daylight at an embankment slope to provide drainage, extend the bridge end backfill 3 feet (915 mm) beyond the wingwall and daylight to the slope facing the span. Place bridge end backfill material in conformance with moisture and density requirements of Section 301 . Do not contaminate bridge end backfill with water while performing bridge work.
301.04 Method of Measurement
301.04.1 Aggregate
Aggregate surfacing, blending material, fillers, binder, water, producing, handling, mixing, hauling, placing, spreading, compacting, trimming, use of trimmings, maintenance, and all necessary incidentals to complete the work is measured by the cubic yard (m3) or ton (MT), as specified. 2020 EDITION V5.1 AGGREGATE SURFACING – 301 301-7 When removing oversize surfacing material from the roadway, the oversize material is measured by the ton (MT) returned to the aggregate source and deducted from the total surfacing material placed on the roadway.
A.Measurement by Weight. Aggregate surfacing is measured by the ton (MT) in accordance with Subsection 301.03.2(C). Excess material removed from the roadway and returned to the pit area is deducted from the pay quantities.
B.Measurement by Volume. Traffic gravel and shoulder gravel are measured by the cubic yard (m3). Aggregate surfacing is measured by the cubic yard (m3), in accordance with Subsection 109.01, from:
1.Plan dimensions.
2.Haul vehicles; or
3.In-place roadway or stockpile volumes. When measured in place, each course thickness of each grade of surfacing aggregate will be measured at random locations in a section. The section length and number of measurements is the Project Manager’s discretion. The thickness measurements for each section are averaged and the average must equal or exceed the plan thickness. The minimum measured thickness at any location must be at least plan thickness less ½ the largest aggregate size permitted for the material. Bring all sections of a completed course not meeting these specifications into compliance before placing the next course. Aggregate surfacing for small or irregularly shaped areas ordered in writing by the Project Manager, are measured in the haul vehicle in accordance with Subsection 109.01 . Aggregate surfacing to fill in subgrade low areas or placed outside the lines and slopes shown in the contract or established by the Project Manager is not measured for payment.
301.04.2 Bridge End Backfill
Bridge end backfill is measured by the cubic yard (m3).
301.04.3 Compaction
Compaction is incidental to the aggregate surfacing.
301.04.4 Crushed Aggregate Course
The entire aggregate surfacing section will be measured as crushed aggregate course regardless of the construction option selected in accordance with Subsection 301.03.4.
301.04.5 Aggregate Treatment
Aggregate treatment is measured by the square area. Blotter material is not measured separately for payment and is to be included in the bid price for aggregate treatment.
301.05 Basis of Payment
Payment for the completed and accepted quantities is made under the following: Pay Item Pay Unit Aggregate Cubic Yard (m3) or Ton (MT) Aggregate Treatment Square Yard (m2) Bridge End Backfill Cubic Yard (m3) Crushed Aggregate Course Cubic Yard (m3) or Ton (MT) Shoulder Gravel Cubic Yard (m3) Traffic Gravel Cubic Yard (m3) 301 – AGGREGATE SURFACING 2020 EDITION V5.1 301-8 Binder is not measured separately but is to be included in the cost for aggregate material. Payment at the contract unit price for traffic gravel includes all costs necessary to furnish and place the gravel. Sale of excess crushed traffic gravel meeting all specifications is the Contractor’s option. Traffic gravel meeting all specifications that is crushed and stockpiled on the project, but not placed or sold, will be paid for at 35% of the contract unit price. Traffic gravel from a commercial source or a source supplying multiple projects and not transported to the project is not measured for payment. If milled/pulverized plant mix is used on any portion of the project, no payment for excess traffic gravel will be made.
Referenced in this section
Aggregate Surfacing in other states
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Source: Standard Specifications for Road and Bridge Construction, 2020 (v5.1) Edition. Pages 205–212 of 611. View official source ↗