321204_crushed_agg_base_or_surface_coarse_R4.pdf

CRUSHED AGGREGATE BASE OR SURFACE COURSE 321204-!Syntax Error, !

USDA FOREST SERVICE, R-4

(PROJECT TITLE)

SECTION 321204 - CRUSHED AGGREGATE BASE OR SURFACE COURSE

PART 1 - GENERAL

1.1 SUMMARY

A. This Section includes furnishing, hauling and placing one or more courses of aggregate base or surface course material on roadways, campground spurs, parking areas, concrete pads, [sidewalks ]and pathways. In addition, may include furnishing, hauling, and placing crushed aggregate for bedding and backfill.

1.2 SUBMITTALS

A. Aggregate source, gradation, and material properties.

1. Submit target values within the gradation ranges shown in Table 321204-1 and /or 321204-2 for the required grading. After reviewing the Contractor’s proposed target values the CO will determine the final values for the gradation and notify the Contractor in writing.

B. Compaction density test results and proctor.

C. Material Properties

1.3 MEASUREMENT AND PAYMENT

CHOOSE One Method of Measurement below:

A. Crushed Aggregate: Number of Cubic Yards of material supplied and installed measured in place to the lines and grades shown on the Drawings. Crushed aggregate shall be used for the construction of roadways, campground spurs, parking areas, concrete pads, sidewalks, pathways and other items as shown on the Drawings.

B. Crushed Aggregate: Number of tons of material supplied and installed. Measurement shall be vehicle weight tickets. Batch masses may be acceptable for determination of pay quantities when an approved automatic weighing, cycling, and monitoring system is included as part of the batching equipment. Crushed aggregate shall be used for the construction of roadways, campground spurs, parking areas, concrete pads, sidewalks, pathways and other items as shown on the Drawings.

EDIT or DELETE paragraph below to match how family/group units are to be paid for.

C. [Family Units and Group Unit Concrete Slabs: Crushed aggregate required for family unit and group unit concrete slabs is considered incidental to those items and will be paid for separately as shown in the Schedule of Items.]

D. No adjustment in a contract unit price will be made for variations in quantity due to differences in the specific gravity or moisture content.

RETAIN paragraph below if Contractor or manufacturer selects testing agency.

PART 2 - PRODUCTS

2.1 AGGREGATES

A. General: Furnish aggregate Subbase, Base, or Surface Courses meeting the gradation ranges shown in Table 321204-1 and Table 321204-2. Aggregate grade selection shall be as shown on the Drawings and in the Schedule of Items.

B. Materials shall be obtained from an approved source. Furnish aggregates that consist of hard, durable particles or fragments of crushed stone, crushed slag, or crushed gravel meeting the appropriate gradation and conforming to the following:

1. Los Angeles abrasion, AASHTO T 96 …...…………………….……... 40% max

2. Sodium sulfate soundness loss (five cycles), AASHTO T 104 ……….. 12% max

3. Durability index, AASHTO T 210 ……………………………………. 35 min

4. Fractured faces, ASTM D 5821 (Subbase or Base)……………………. 50% min

5. Fractured faces, ASTM D 5821 (Surface Course).……………………. 75% min

6. Free from organic matter and lumps or balls of clay.

C. Obtain the aggregate gradation by crushing, screening, and blending processes as necessary.

2.2 AGGREGATE GRADATION

SPEC WRITER: The grading categories are different from the former CSI Section 02240.

Please read carefully.

Table 321204-1, Crushed Aggregate Grading Requirements for Subbase and Base.

Percent Passing (AASHTO T27 and T11)

Sieve Grading A (Subbase)

Grading B (Subbase)

Grading C (Base)

Grading D (Base)

Grading E (Base)

2 1/2 -inch 100 2-inch 97-100 100 100 1-1/2-inch 97-100 1-inch 65-79 (6) 80-100 (6) 100 3/4-inch 60-94 (6) 86-100 (6) 100 1/2-inch 45-59 (7) 3/8-inch 40-69 (6) 51-82 (6) 62-90 (6) No. 4 28-42 (6) 40-60 (8) 31-54 (6) 36-64 (6) 36-74 (6) No. 40 9-17 (4) 12-26 (4) 12-26 (4) No. 200 4-8 (3) 4-12 (4) 4-7 (3) 4-7 (3) 4-7 (3)

() The value in the parentheses is the allowable deviation (+ / - ) from the target values.

Liquid Limit, AASHTO T89 = 25 max. Plastic Limit, AASHTO T-90 = nonplastic.

Table 321204-2, Crushed Aggregate Grading Requirements for Surface Course.

Percent Passing (AASHTO T27and T11)

Sieve Grading F (Surface Course)

Grading G (Surface Course)

1-1/2-inch 100 1-inch 97-100 100 3/4-inch 76-89 (6) 97-100 1/2-inch 3/8-inch 56-68 (6) 70-80 (6) No. 4 43-53 (7) 51-63 (7) No. 8 No. 16 23-32 (6) 28-39 (6) No. 40 15-23 (5) 19-27 (5) No. 200 10-16 (4) 10-20

() The value in the parentheses is the allowable deviation (+ / - ) from the target values.

Liquid Limit, AASHTO T 89 = 35 max, Plastic Index, AASHTO T90 = 2 to 9 if percent passing the No. 200 sieve is less than 12% and less than 2 if the percent passing the No. 200 sieve is greater than 12%.

If the plasticity index (PI) is greater than 0, the TV range for the No. 200 sieve size is 8-12 (4).

PART 3 - EXECUTION

3.1 GENERAL

A. Verify that subgrade is dry and in suitable condition, locate areas that are unstable or that require further compaction.

B. Proceed with aggregate placement only after unsatisfactory conditions have been corrected and subgrade is approved in writing by the Contracting Officer (CO).

3.2 PREPARATION OF SUBGRADE

A. The subgrade shall be prepared in accordance with requirements of other specifications sections.

B. The subgrade shall conform to the lines and grades shown on the Drawings. Suitable material shall be utilized in the preparation of the subgrade. When embankment or fill is necessary, subgrade shall be placed in compacted layers not exceeding 6 inches.

Unless specified otherwise, subgrade shall be compacted to 95 percent of AASHTO T 99, method C or D.

C. Suitable material for subgrade shall be granular material or fine compatible soil free of excess moisture, muck, frozen lumps, roots, sod, and other deleterious material.

Remove all rock particles and hard earth clods larger than 3 inches in the longest dimension.

3.3 MIXING AND SPREADING

A. Mix the aggregate and adjust the moisture content to obtain uniform moisture. Spread and shape the mixture on the prepared surface in a uniform layer not to exceed 6 inches in compacted thickness.

B. Route hauling equipment uniformly over the full width of the surface to minimize rutting or uneven compaction.

3.4 COMPACTING

A. Compact each layer of aggregate full width. Compact each layer to a density of at least 95 percent of the maximum density as determined by AASHTO T 99 method C or D.

B. Testing shall be at intervals specified in tables shown in Section 014100 “Quality Control.”

3.5 SURFACE AND CONSTRUCTION TOLERANCES

A. Shape the surface to the required template and as staked. Surface shall be graded and shaped smooth to within ½-inch in 10 feet.

B. Maintain the aggregate course to the correct lines, grade, and cross-section by blading, watering, and rolling until placement of the next course.

C. Upon completion of full placement and after haul trucks have completed their haul across section of the road, the road shall be finish bladed, watered, and rolled.

D. Aggregate shall be placed as shown on the drawings and as staked. Tolerance for thickness of aggregate shall be +/– ½-inch and for width shall be + 1-foot.

3.6 ACCEPTANCE

A. Aggregate shall be accepted following placement when shown to meet material quality, gradation, compaction requirements, required depth and width, and finish blading.

REVISION HISTORY:

PRIMARY AUTHOR: JUSTIN HUMBLE, WRITTEN DURING THE

WATER/WASTEWATER SPEC-WRITING SESSION IN JANUARY, 2004.

REPLACES: CSI SECTION 02240

2/2005: REVIEWED AND EDITED BY D. WEWER, B. LUDVIGSEN.

3/21/2006: D. Wewer - Updated Section to new numbering system.

3/28/06: D.Jeppsen – review/update of specification

3/29/2011 D. Wewer: Made changes to measurement and payment paragraphs per comments from Scott Bingham.

11/21/2016 D. Wewer: Edited No. 200 range for Grading G gravel per Todd Touchard.

Changed from 10-16 (4) to just a straight 10-20 with no deviation. This will help us ensure we have enough fines (binder – silts/clays).

END OF SECTION 321204

March 2024