FHWA FP-24Public Domain

Section 301 — Untreated Aggregate Courses

Division 300 — Aggregate and Base Courses|PDF pages 254–261

Description

301.01This work consists of cons tructing aggregate courses on a prepared surface.

Material

301.02Conform to the following Subsections: Subbase, base, and surface course aggregate 703.05 Water for construction 725.01(c)

Construction Requirements

301.03General. Prepare the surface according to Section 204 or 303 as applicable. After a representative quantity of aggrega te is produced, submit target values within the required gradation range along with a representative 300- pound sample at least 14 days before incorporating the aggregate into the work.

301.04Mixing and Spreading. Determine the optimum moisture content ac cording to AASHTO T 180, Method D. Mix the aggregate and adjust the moisture content to obtain a uniform mixture with a moisture content within 2 percent of the optimum moisture content. Spread and shape the mixture on the prepared surface in a uniform lift. Place mixture in a lift no more than 6 inches in compacted thickness. If more than one lift is necessary, compact each lift according to Subsection 301.05 before placing the next lift. Route hauling equipment uniformly over the full width of the surface to minimize rutting or uneven compaction.

301.05Compacting. Determine the maximum density of the mixture according to AASHTO T 180, Method D. Compact the full width of each lift. Roll from the sides to the center, parallel to the centerline of the road. Along curbs, headers, walls, and places not accessible to the roller, compact the material with approved tampers or compactors. Compact each lift to at least 95.0 percent of maximum density. Determine th e in-place density and moisture content according to AASHTO T 310 or other approved test procedures.

301.06Surface Tolerance. If grade finishing stakes are required, finish the surface to within ±0.05 feet from staked line and grade elevation. If AMG met hods are used, finish the surface to within ±0.05 feet from the design line and grade elevation. If grade finishing stakes are not required and AMG methods are not used, shape the surface to the required template and check the surface with a 10 -foot metal straightedge. Defective areas are surface deviations more than ½ inch in 10 feet between two contacts of the straightedge with the surface. Correct defective areas by loosening the material, adding or removing material, reshaping, and compacting.

301.07Maintenance. Maintain the aggregate course to the correct line, grade, and cross -section by blading, watering, rolling, or combination thereof until placement of the next course. Correct defects according to Subsection 301.06.

301.08Acceptance. See Table 301-1 for sampling, testing, and acceptance requirements. Aggregate gradation and surface course plasticity index will be evaluated under Subsection 106.05 . Other aggregate quality properties will be evaluated under Subsections 106.02 and 106.04.

(a)Aggregate gradation. The upper and lower specification limits are equal to the calculated mean of all test results plus or minus the allowable deviations shown in Tables 703-1 and 703-2, except as follows:

(1)If the calculated mean value for a tested sieve exceeds the maximum gradation range value shown in Table 703-1, then the upper specification is equal to the maximum gradation value in Table 703-1 plus or minus the allowable deviation in Table 703-2.

(2)If the calculated mean value for a tested sieve is less than the minimum gradation range value shown in Table 703-1, then the lower specification is equal to the minimum gradation value in Table 703-1 plus or minus the allowable deviation in Table 703-2.

(b)Plasticity index. The upper and lower specification limits for surface courses are shown in Subsection 703.05(c)(3) . Construction of untreated aggregate courses will be evaluated under Subsections 106.02 and 106.04.

Measurement

301.09Measure the Section 301 pay items listed in the bid schedule according to Subsection 109.02 and the following as applicable: When measuring aggregate by the cubic yard, measure in place. When measuring aggregate by the square yard, measure the length horizontally along the centerline of the roadway. Measure the width horizontally to include the top of aggregate width, including designed widenings.

Payment

301.10The accepted quantities will be paid at the contract price per unit of measurement adjusted according to Subsection 106.05 for the Section 301 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this S ection. See Subsection 109.05. Table 301-1 Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Source

Aggregate

quality (703.05(a) , (b), & (c)) Measured & tested for conformance (106.04 & 105) LA abrasion (coarse) − AASHTO T 96 1 per type & source of material Source of material Yes Before using in work Not required if using

Government

-furnished sources

Soundness

using sodium sulfate (coarse & fine) − AASHTO T 104 " " " " "

Fractured

faces − AASHTO T 335 " " " " " Liquid limit − AASHTO R58 & T 89, Method A " " " " "

Surface course

aggregate (703.05(c) ) Measured & tested for conformance (106.04 & 105) Plasticity index − AASHTO R 58, T 89, & T 90 1 per type & source of material Crusher belt or after processing Yes Before using in work Not required if using

Government

-furnished sources Table 301- 1 (continued) Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Source (continued)

Subbase, base,

or surface course aggregate (703.05(b) & (c)) Process control (153.03 ) Gradation − AASHTO T 11 & T 27 2 per day per stockpile minimum Crusher belt No 24 hours Not required if using a pre - crushed commercial source Fractured faces − AASHTO T 335 " " " " "

Surface course

aggregate (703.05(c) ) " Plasticity index − AASHTO R 58, T 89, & T 90 2 per day per stockpile minimum Crusher belt or after processing No 24 hours Not required if using a pre- crushed commercial source

Production

Subbase

course

Grading

A & B Statistical

(106.05 ) Gradation

AASHTO

T 27 & T 11 1 per 1000 tons From windrow or roadbed aft er processing Yes 4 hours − No. 4 I No. 200 I

Other

specified sieves II Table 301- 1 (continued) Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Production (continued)

Base course

Grading C,

D, & E Statistical

(106.05 ) Gradation

AASHTO

T 27 & T 11 1 per 1000 tons From windrow or roadbed after processing Yes 4 hours − ⅜ in I No. 4 I No. 200 I

Other

specified sieves II

Subbase &

base course

Grading A,

B, C,

D, & E Measured &

tested for conformance (106.04 ) Liquid limit − AASHTO R 58 & T 89, Method A 1 per 1000 tons From windrow or roadbed after processing Yes 4 hours −

Moisture -

density (maximum density) − AASHTO T 180, Method D(1) 1 per type & source of material Stockpile or production output " " − Density − AASHTO T 310 or other approved procedures 1 per 500 tons In-place after compaction No End of shift −

Moisture

content (in-place) − " " " " " − Table 301- 1 (continued) Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Production (continued)

Surface

course aggregate Statistical (106.05 ) Gradation

AASHTO

T 27 & T 11 1 per 1000 tons From windrow or road bed after processing Yes 4 hours − No. 4 I No. 40 I No. 200 I

Other specified

sieves II

Plasticity index I AASHTO

R 58, T 89, & T 90 " " " " −

Measured &

tested for conformance (106.04 ) Moisture - density (maximum density) − AASHTO T 180, Method D(1) 1 per type & source of material Stockpile or production output Yes " − Density − AASHTO T 310 or other approved procedures 1 per 500 tons In-place after compaction No End of shift −

Moisture

content (in-place) − " " " " " −

Fractured

faces − AASHTO T 335 1 per 1000 tons From windrow on roadbed after processing Yes 4 hours − Table 301- 1 (continued) Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Finished Product

Subbase, base,

& surface course Measured & tested for conformance (106.04 ) Surface tolerance & grade − Subsection

301.06As directed Surface of final course No Before placement of next lift or as requested −

(1)At least 5 points per proctor.

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