A06_BASE_COURSES.pdf

Rehabilitate the Old El Portal Debris Basin, Gabion, and Service Road Specifications 5/2025

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BASE COURSES

SECTION 32 11 00

PART 1 GENERAL

1.1 WORK SUMMARY

A. This section covers the requirements to perform work including but not limited to the operations to furnish, transport, place, grade and compact subbase and aggregate base (AB) materials for all the applications as shown on the Drawings and as specified for the work.

B. Provide all labor, materials, tools, equipment, services, and incidentals as necessary to perform the work as described in this section and in accordance with the Contract Documents and Drawings and to the satisfaction of NPS.

C. At the Contractors option, and acceptance of the NPS representative, applications for base courses may include work for pulverizing an existing asphalt pavement and base in-place, adding crushed aggregate to supplement the pulverized material to meet specified traffic index requirements, mixing to produce a homogenous full depth structural mixture, and spreading, shaping and compacting to produce a recycled aggregate base section for roadways as specified for the work. Compensation for pulverization or production of recycled base on-site, including full installation, shall be considered included in costs paid for other items of work involved and no additional compensation provided.

1.2 RELATED WORK

A. Attention is directed to the General Requirements and related work specified in other sections includes, but is not limited to:

1. Section 32 12 00, Flexible Paving

2. Section 32 15 00, Aggregate Surfacing

1.3 DEFINITIONS

A. Not Used.

1.4 SUBMITTALS

A. Submittals shall be in conformance with Contracting Requirements, Specifications, and Division 1 - General Requirements.

B. At least 14 days prior to placement of any subbase or aggregate base in the work, the Contractor shall submit supporting documentation to indicate the source and material properties for each subbase or aggregate base material to be placed in the work meets the Specification requirements, including laboratory optimum moisture-maximum density curves (AASHTO T

180) necessary for field quality control testing.

C. Provide copies of certifications for material testing personnel and laboratories to be used for Contractor Quality Control.

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D. Provide required documentation for all Contractor Quality Control material testing as noted in the specifications.

1.5 REFERENCES

A. The Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects (FP-14), dated 2014; and published revisions thereto.

https://flh.fhwa.dot.gov/resources/specs/

1. Payment descriptions in the FP-14 Standard Specifications shall not apply.

2. In case of conflict with the FP-14 Standard Specifications, the most stringent specification shall apply.

3. “Contracting Officer” as stated in the FP-14 Standard Specifications shall generally be defined as the CEO and General Manager of NPS or the authorized representative for the purposes of these Specifications.

4. References to Transportation Acquisition Regulations (TAR), and references to Federal Acquisition Regulations (FAR) shall not apply.

B. Applicable ASTM and AASHTO standards.

C. A reference within parentheses to a law or regulation is included in the Contract for convenience only and is not a comprehensive listing of related laws and regulations. Lack of a reference does not indicate no related laws or regulations exist.

D. Where the version of a referenced document is not specified, use the most recent version in effect on the date of the Notice to Bidders.

E. A code not specified as a federal code is a California code.

F. An agency or a department not specified as a federal or local agency or department is a California agency or department.

1.6 QUALITY ASSURANCE

A. Conform to the Contract Documents including but not limited to, Technical Conditions, Drawings, and Standard Specifications.

B. Conform to the sampling, testing and acceptance requirements of Sections 301.08 and 304.10 of the FP-14 Standard Specifications, for the materials that applies.

C. Testing Agency: NPS may engage a qualified independent geotechnical engineering and/or material testing agency/consultant to perform field quality-control acceptance testing.

D. Inspection: The Contractor shall coordinate with the NPS Representative during all earthwork and base course operations to allow for access to the site as often as necessary for the performance of any special inspections and material testing for verification that the specifications are being met for the installation of materials. Frequency of material testing shall conform to the applicable Specifications, Standards and Test Methods.

E. All Contractor required ‘Quality Control’ materials testing shall be based upon applicable ASTM and AASHTO Test Methods referenced herein for the materials specified. All https://flh.fhwa.dot.gov/resources/specs/

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equipment, material, and labor necessary for Quality Control testing shall be supplied by and all costs borne by the Contractor.

1. Provide copies of all applicable testing procedures and standards (per ASTM and/or

AASHTO).

2. Provide certifications for calibration of all field-testing equipment.

3. A report of any field test results and laboratory testing shall be furnished.

4. All deficiencies, which become present from testing shall be rectified, and the materials retested until passed, or materials replaced where non-conforming.

5. All tests shall be performed in the presence of the NPS Representative or designated representative.

1.7 PROJECT CONDITIONS AND REQUIREMENTS

A. All imported base courses and aggregate materials shall be sourced from an accepted supplier, meeting the contract compliance requirements, and certified weed free. Do not change suppliers during course of work unless authorized by NPS.

B. A limited Geotechnical Site Assessment was previously completed at the project site and a copy of the report is included with the Contract Documents. In this report recommendations for allowable foundation design parameters, site grading, and pavements are defined.

1.8 TOLERANCES

A. Conform to surface tolerance requirement of Section 301.06 of the FP-14 Standard Specifications

B. Minimum thicknesses and slopes shall be as shown on the Drawings.

C. The surface of the finished AB material at any point shall not vary more than 0.05 feet above or below the grade established by the Engineer and as shown on the Drawings.

D. Where HMA is to be placed, the grading plane at any point shall not be more than 0.05 foot above the grade established by the Engineer and as shown on the Drawings.

E. Where PCC pavement or structures is to be placed, the grading plane at any point shall not be more than 0.05 foot above the grade established by the Engineer and as shown on the Drawings.

PART 2 PRODUCTS

2.1 SUBBASE AND AGGREGATE BASE

A. Conform to Section 703.05, Subbase, Base, and Surface Coarse Aggregate of the FP-14 Standard Specifications.

B. In addition to the aggregate quality characteristics specified in the FP-14 Standard Specifications, conform to the following:

1. Subbase

a. Sand equivalent (min), AASHTO T176 21

b. Resistance (R-value, min), AASHTO T 190 50

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2. Aggregate Base (AB)

a. Plastic limit, AASHTO T 90 nonplastic

b. Sand equivalent (min), AASHTO T176 25

c. Resistance (R-value, min), AASHTO T 190 78

C. Aggregate “Grading Designation” shall be as specified for each improvement type and area as shown on the Drawings. Grading Designation shall conform to Table 703-2, Target Value Ranges for Subbase and Base Gradation of Section 703.05(b) of the FP-14 Standard Specifications.

1. An equivalent gradation class of material, per Caltrans Standards, may be substituted based on available supply, review, and acceptance of submittals.

PART 3 EXECUTION

3.1 GENERAL

A. Applicable construction operations for earthwork, excavation and fill shall conform to Section 31 23 00, Excavation and Embankment.

B. Conform to Section 301, Untreated Aggregate Courses of the FP-14 Standard Specifications.

C. All subbase and AB material used for the work shall be of the class/grading for each improvement type and area as shown on the Drawings and as specified in these Specifications.

D. Contractor shall furnish, transport, place, shape, compact, grade, and otherwise apply all subbase and AB material as necessary to construct and complete all project improvements involved as shown on the Drawings, as specified in these Specifications, and as otherwise directed by NPS.

E. Maintain base courses with sufficient moisture and avoid rutting from excess travel impacts.

Correct any irregularities or depressions by adding additional bases course materials, smooth, and compact to maintain a uniform finish to the required tolerances.

3.2 STORAGE OF MATERIALS

A. Subbase and AB materials may only be stockpiled at staging and storage areas identified on the Drawings and in accordance with the SWPPP and Project Permits and shall not be stockpiled in a manner that destroys or damages existing vegetation in areas not shown on Drawings for excavation or grading.

1. Place, grade, and shape stockpiles to drain surface water.

2. Stockpile materials away from edge of excavations. Do not store within drip line of trees to remain.

3. Cover all stockpiles at the end of each day’s work, and when operations are inactive to prevent windblown dust or erosion from precipitation.

B. Any stockpiles of subbase and AB material shall be protected from contamination with earthen or other unsatisfactory material that may destroy the quality and fitness of the suitable stockpiled material. If the Contractor fails to protect the stockpiles and any material becomes

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unsatisfactory as a result, such material shall be removed and replaced at no additional cost to

NPS.

C. Areas disturbed by the stockpiling of materials outside of designated staging and storage areas shall be revegetated at the Contractors expense, and no additional compensation will be allowed.

3.3 SUBGRADE PREPARATION

A. Preparation of the subgrade and/or surface on which aggregate courses are placed shall conform to Section 301.03 of the FP-14 Standard Specifications.

B. Before placement and spreading of any subbase or AB materials, the subgrade or underlying materials must comply with the specified compaction, elevation tolerance, and slopes for the material involved and be free from loose or extraneous material.

C. Ruts or soft yielding spots in the subgrade, areas having inadequate compaction, and deviations of the surface from the requirements set forth herein shall be corrected by loosening and removing soft or unsatisfactory material and by adding approved material, reshaping to line and grade, and compacting to specified density requirements.

D. The finished subgrade or underlying surface shall not be disturbed by traffic or other operations and shall be maintained by the Contractor in a satisfactory condition until the base course is placed.

E. If the finished subgrade or underlying surface are lower than the grade established by the Engineer and as shown on the Drawings, the applicable overlying material may be placed to fill the low areas. Any subbase or AB placed to fill low areas is not included in the quantity for payment.

3.4 SPREADING

A. Mixing and spreading of aggregate courses shall comply with Section 301.04 of the FP-14 Standard Specifications.

B. Subgrades must be inspected and approved by NPS prior to placing base course.

C. Deliver uniform mixtures of subbase or AB material to the specified location and deposit in layers or windrows.

D. Spread and shape subbase or AB to such thickness that after watering and compacting, the completed section is within the tolerances specified.

E. When subbase or AB is spread the moisture content must be uniform and sufficient to obtain required compaction. Moisture conditioning loose materials before compaction to within at least 2 percent of optimum moisture will yield best results.

F. Avoid material segregation. Subbase or AB materials must be free from pockets of coarse or fine material. Upon visual inspection, correction of deficiencies may be required.

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G. Where the shown subbase or AB finished thickness is 0.5 foot or less you may spread and compact the material in one layer. Where the shown finished thickness is more than 0.5 foot, spread and compact the material in 2 or more layers approximately equal in thickness; the compacted thickness of any one layer must not exceed 0.5 foot.

3.5 COMPACTING

A. Compaction of aggregate courses shall conform to Section 301.05 of the FP-14 Standard Specifications.

B. Compact materials to no less than the specified in-place density (AASHTO T 310) as specified on the Drawings.

C. Compact the full width and depth of the fill and embankment to the limits of the work as shown on the Drawings. Rolling patterns shall progress from the sides to the center.

D. For trench compaction, flooding or jetting will not be allowed.

E. The finished surface shall be within the tolerances specified, at the grade established by the Engineer and as shown on the Drawings.

F. Proof Rolling: Upon completion of the subject layer and any density testing, the Contractor shall demonstrate to the NPS Representative, upon request, that the exposed layer does not contain unidentified soft areas by proof rolling. Proof rolling shall consist of rolling the entire surface with approved mechanical equipment while observing the grade for displacement or deformation.

G. When testing or proof rolling indicates that materials have not achieved degree of compaction specified, scarify and moisten or aerate, or remove and replace to depth required; compact and retest until specified compaction is obtained.

3.6 FULL DEPTH RECLAMATION, MECHANICAL STABILIZATION & ROAD GRADING

A. Where Drawings identify or contractor elects to pulverize existing roadway in place, conform to Section 304, Full Depth Reclamation of the FP-14 Standard Specifications.

B. Roadway grading shall conform to Section 31 23 00, Excavation and Embankment. Surplus earthen, subgrade or structural backfill material generated from roadway grading operations shall not be prematurely disposed to ensure enough material is available to complete the fills and embankments at other locations on the job site.

C. Any pulverized roadway material is to be windrowed and/or stockpiled as necessary to facilitate roadway grading to the profile, cross slope, lines and grades as shown on the Drawings and established by the Engineer.

D. Material sampling, testing and structural pavement design for acceptance and conformance of a pulverized roadway base material and establishment of any required crushed aggregate supplement to meet a minimum Traffic Index (TI=6.0) is the responsibility of the Contractor.

1. Material sampling and testing performed by the Contractor, shall conform to Section 153, Contractor Quality Control of the FP-14 Standard Specifications. Material testers, YOSE - 340955 32 11 00 - 7 inspectors and laboratories must be certified under National Institute for Certification in Engineering Technologies (NICET) and a regional certification program, or equivalent, to perform the required ASTM and/or AASHTO test methods.

E. Add crushed aggregate to pulverized material where required (based on structural pavement design results) to meet the minimum Traffic Index. Crushed aggregate shall conform to Section

703.06 of the FP-14 Standard Specifications. Moisture condition and mix the pulverized and crushed aggregate materials to produce a homogenous full depth material mixture.

F. Spread, shape, and compact the material mixture uniformly across the roadbed to meet the lines and grades shown on the Drawings and established by the Engineer to produce a complete roadway base structural section.

END OF SECTION