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Base Course

(Section 02230)

PART 1 GENERAL

1.01 WORK INCLUDED

A. Contractor shall provide all materials, labor, tools, equipment, fees, permits, transportation and other items required to furnish and install base course materials as indicated or as required to accomplish Work of other sections of these specifications. Base course Work shall include, but not be necessarily limited to the following:.

     1. Subgrade preparation to lines and grades shown on the plan.

     2. Place, grade and compact base and sub-base course materials.

     3. Dust and surface water control.

1.02 RELATED WORK

A. Section 02220 - Excavating, Backfilling and Compaction

     1. Subgrade preparation and compaction requirements

B. Section 02511 - Asphaltic Concrete Paving

C. Section 02513 - Concrete Sitework

     1. Curbs, Walks and Driveway Aprons

1.03 REFERENCES

A. The applicable provisions of the latest editions of the References listed below shall govern the Work covered under this Section, unless there is a conflict between said References and the requirements of this Section. In the case of such a conflict, the requirements of this Section shall apply.

B. American Society for Testing Materials (ASTM).

C. American Association of Safety and Highway Transportation Officials (AASHTO)

D. Utah Occupational Safety and Health Division (UOSHD)

E. Utah Department of Transportation (UDOT)

F. Midvale City Corporation Standard Construction Details


1.04 SUBMITTALS

A. Submit evidence of materials conformance with applicable requirements as well as these specifications.

1.05 QUALITY ASSURANCE

A. Comply with federal, state, and local codes and regulations.

B. All working conditions shall be in accordance with the "Utah Occupational Safety and Health Division", Safe Practices for Excavation & Trenching Operations, latest edition, or other Laws or Regulations which apply.

C. Salt Lake County requirements shall govern for all work in Salt Lake County road right-of-ways:

     1. All work shall conform to the applicable standards, regulations, and requirements of the Salt Lake County Public Works Department.

     2. Permits shall be obtained and paid for by the Contractor.

     3. License and Permit Bond, without cancellation clause, in an amount and form prescribed by the Salt Lake County Department of Public Works, shall be provided by the Contractor in connection with excavations in Salt Lake County Right-of-Way.

D. Utah Department of Transportation requirements shall govern for all work in Utah Department of Transportation highway right-of-ways:

     1. All work shall conform to the applicable standards, regulations and requirements of the Utah Department of Transportation, including the Specifications for Excavation on State Highways.

     2. Permits shall be obtained and paid for by the Contractor.

     3. License and Permit Bond, without cancellation clause, in an amount and form prescribed by the Utah Department of Transportation, shall be provided by the Contractor in connection with his excavations on Utah Department of Transportation Right-of-Way.

E. Utah Department of Transportation requirements in Salt Lake County Roads:

     1. Where reference is made to Utah Department of Transportation standards in these Specifications for work in Salt Lake County roads, the work shall conform to the applicable Utah Department of Transportation standards.

F. Extended Warranty Period for work in Salt Lake County and Utah Department of Transportation roadways shall apply.

1.06 DELIVERY, STORAGE AND HANDLING

A. All base course materials shall be hauled, delivered, stored and handled in such a manner as to prevent contamination of base course material.

1.07 PROJECT CONDITIONS

Not Used

PART 2 PRODUCTS

2.01 MANUFACTURERS

A. Materials suppliers shall provide, upon request, verification of a consistent record of meeting or exceeding materials or performance standards as specified herein.

2.01 BASE COURSE MATERIAL

A. Road Base for Concrete Curb and Gutter, and Waterways.

     1. Unwashed, hard, durable, angular pit run gravel or crushed natural stone.

     2. Shall be free from shale, silt, clay, loam, friable or soluble materials.

     3. Shall be free from noticeable concentrations of alkali, salt, and petroleum products, all roots, sod, limbs, and other vegetative matter, slag, cinders, ashes and rubbish, or other material that, in the opinion of the Engineer, is objectional or deleterious.

     4. Shall be graded within the following limits:

          Sieve Size Percent Passing By Weight

          1" 100
          3/4" 90-100
          1/2" 30-60
          3/8" 0-20
          #4 0-5

B. Road Base for Pavement Preparation:

     1. Shall be untreated natural stone

     2. Shall not be lumpy or frozen.

     3. Shall be free from noticeable concentrations of alkali, salt, shale, and petroleum products, all roots, sod, limbs, and other vegetative matter, slag, cinders, ashes and rubbish, or other material that, in the opinion of the Engineer, is objectional or deleterious.
 

     4. Shall be graded within the following limits:

          Sieve Size Percent Passing By Weight

          1" 100
          1/2" 70-100
          No. 4 41-68
          No. 16 21-41
          No. 40 10-27
          No. 200 4-13

PART 3 EXECUTION

3.01 EXAMINATION

A. It shall be the Contractor's sole responsibility to locate all (whether or not shown on the Drawings) existing water, sanitary sewer, storm drain, and gas lines, electrical and telephone conduit and other underground utilities with their existing house service connections, and all other underground structures in order that no damage or loss of service will result from interference with existing lines.

B. Review all available drawings, notes, and information on the location of these underground lines and structures in determining the location of the existing facilities.

C. Have an electronic pipe finder on the job at all times and mark all lines on the road ahead of the excavating machine.

D. Blue Stakes Location Center shall be contacted 48 hours before any excavation is commenced. Phone 532-5000 for assistance.

E. Mark with paint any existing cracks on concrete along which work will take place, in order to determine after the construction is completed whether such damage was caused by the operations of the Contractor or had occurred previously. Any concrete showing unmarked cracks upon completion of construction shall be evidence of damage caused by the Contractor, and shall be replaced or repaired to the satisfaction of the Owner of the damaged concrete, at the Contractor's sole expense.

F. All fences removed for excavation shall be returned to their original condition except that damaged portions will be replaced with new fencing at the Contractor's expense.

G. Obtain all required permits.

3.02 METHODS AND PROCEDURES

A. General Requirements

     1. All gas, sanitary sewer, storm drain, water and other pipelines, flumes and ditches of metal, wood or concrete, underground electrical conduits and telephone cable, and all walks, curbs, and other improvements encountered in excavating for base course shall be supported, maintained and protected from injury or interruption of service until installation is complete

     2. If any existing facility is damaged or interrupted, promptly after becoming of the same and before performing any Work affected thereby, identify the owner of such existing facility, and give written notice thereof to that owner and Midvale City.

     3. All damage, injury or loss resulting from lack of adequate sheeting, bracing, and shoring shall be the responsibility of the Contractor; and the Contractor shall effect all necessary repairs or reconstruction resulting from such damage.

3.03 INSTALLATION

A. Preparation of Subgrade

     1. Prior to placing base course materials, the subgrade shall be scarified to a depth of not less than 6", moistened or dried to optimum moisture content, and compacted to at least 96% maximum Modified Proctor Density as determined in accordance with ASTM D1557 (AASHTO T-180), and shall be within 2% of optimum moisture content.

     2. The subgrade shall then be proof rolled in the presence of the Engineer by passing loaded rubber-tired construction equipment uniformly over the surface at a constant rate. At least two (2) passes shall be made over all subgrade areas.

     3. If excessively soft, loose, or disturbed soils are encountered, they shall be removed as directed by the Engineer to a maximum depth of two feet (2') and replaced and recompacted to 96% maximum Modified Proctor Density using approved subgrade stabilizing material.

     4. Ensure subgrade is to required lines and elevations.

B. Placement of Base Course

     1. Protect against "pumping" moisture to surface by limiting travel on exposed subgrade. Where it is determined by the Owner that construction vehicle traffic (other than proof rolling) has caused subgrade instability, remove disturbed soils and replace with sand backfill at no additional cost to the Owner.

     2. Apply water soluble herbicide for nonselective control of annual and perennial weeds in strict accordance with manufacturers instructions and all laws and regulations.

     3. Place base course material on the prepared and accepted subgrade. The material shall be back-dumped and spread in a uniform lift thickness.

     4. Handle and spread materials in a manner that will prevent segregation of sizes. When vibrating or other acceptable types of compaction equipment are used, the entire course may be placed in one layer, provided the ability of the equipment to achieve specified compaction to the full layer depth is demonstrated. In no case shall compacted lift thickness be greater than 8".

     5. When base course is constructed in more than one layer, the previously placed layer shall be cleaned of loose and foreign matter. Upper layer of base course shall not be less than 1-1/2", nor shall fine materials be added to reach final grade.

     6. Overstressing the subgrade soil and base course shall be avoided by utilizing equipment in spreading and dumping that exerts only moderate pressures on the soil. Avoid excessive travel on lower base course lifts. Severe rutting, cracking or yielding is an indication of overstressing the soil. Any ruts or cracks which develop in the base course during spreading or compacting shall be repaired as directed at no additional cost to Owner.

     7. Base course shall be compacted to no less than 96% maximum Modified Proctor Density, as determined by ASTM D1557 (AASHTO T-180). Moisture content shall be maintained to within 1.5% of optimum throughout placing and compaction operations.

          a. Compaction shall always be commenced along the edge of the area to be compacted and the roller shall gradually advance toward the center of the area to be compacted.

          b. Compaction equipment shall be operated along lines parallel or concentric with the centerline of the road being constructed, and no material variation therefrom will be permitted.

     8. Base course shall be substantially true to line and grade as indicated on the drawings. The surface shall be within 1/2" of required grade. Completed thickness of base course shall be within 1/2" of indicated thickness, with average thickness not less than that indicated.

     9. The top surface of compacted base course shall be finished by blading or rolled with equipment designed for that purpose.

     10. Temporary Graded Surface

          a. When allowed by the local jurisdiction having authority, where trenches are excavated in paved traffic lanes, the surface course may be temporarily replaced by a surface consisting of base course material. The base course shall be removed and replaced with pavement as soon as conditions permit, or as required by local jurisdiction having authority.

          b. The surface shall be maintained to provide for a smooth flow of traffic without holes, bumps, etc., until final acceptance of the work.

C Dust and Surface Water Control

     1. Dust control measures shall be implemented by application of water to all work areas, storage areas, haul and access roads, or other areas affected by work.

     2. All work shall be in compliance with the Federal, State and local air pollution standards, and not cause a hazard or nuisance to personnel and the public in the vicinity of the work.

     3. Provide and operate at least one (1) mobile tank sprinkling unit during the contract period.

     4. Other methods of dust control for haul and access roads may include chemical treatment, light bituminous treatment or other method as approved by the Owner.

     5. Surface water shall be controlled to the extent that the areas to receive pavement, walks or slabs are not allowed to become wet from runoff from adjacent areas. Surface water shall be directed away from these areas but not directed toward adjacent property, buildings, or any improvement that may be damaged by water. Surface water shall not be allowed to enter sanitary sewers.

3.04 PROTECTION

A. Provide barricades and restrict access as appropriate to prevent damage to Work in place.

B. Contractor shall be responsible for protection of Work in place against displacement, damage, or loss until Owner's acceptance. Any work and subsequently damaged, lost or displaced shall be repaired or replaced to the Owner's satisfaction at no additional cost.

3.05 TESTING

A. Testing and inspection of placed Base Course will be provided by the Owner. Tests provided by the Owner are as follows:

Item Type Frequency

Base Course Aggregate Sampling ASTM D75 Each day or 1 test/500 sq. yd., or as required.

Atterberg Limits ASTM D2419, As required
D423, and D424

Sieve Analysis ASTM C136 As required

Bearing Ratio ASTM D1883 As required

Maximum Density ASTM D1557, As required
Method D

In-place Density ASTM D2167, As required
D2922 and D3017

B. If tests indicate that sub-base and/or base course do not meet specified requirements, remove defective work, replace and retest at no cost to Owner.

3.06 CLEANING

A. Thoroughly clean, rake, wash, flush or sweep as required to clean adjacent improvements of materials covered as part of this Work prior to submitting for Owner's acceptance.

B. Contractor shall provide all labor, equipment, materials and other items as required to perform clean up as required by the Owner, adjacent property owners and other jurisdictions.

C. Finish grading of areas affected by this Work shall be required as part of clean up.