A06_ROAD_BASE_NM_SUPPLEMENT_ATTACHMENT_A.pdf

SUPPLEMENTAL SPECIFICATIONS

Supplement to the 2000 Edition of the Standard Specifications

For Highway and Bridge Construction

March 2004

New Mexico Department of Transportation

NEW MEXICO DEPARTMENT OF TRANSPORTATION

TABLE OF CONTENTS

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DIVISION 200 - EARTHWORK

Sections Page

203 EXCAVATION, BORROW, AND EMBANKMENT 203-1 to 203-21

206 EXCAVATION AND BACKFILL FOR CULVERTS AND MINOR

STRUCTURES

206-1 to 206-3

210 STRUCTURE EXCAVATION AND BACKFILL FOR BRIDGES 210-1 to 210-3

DIVISION 300 - BASES

303 BASE COURSE (QC/QA) 303-1 to 303-6 304 BASE COURSE (NON QC/QA) 304-1 to 304-7 306 CEMENT AND LIME TREATED SUBGRADE 306A-1 to 306B-10

DIVISION 400 - SURFACE TREATMENTS AND PAVEMENTS

401 PAVEMENT SMOOTHNESS MEASUREMENT 401-1 to 401-10

402 BITUMINOUS MATERIALS, HYDRATED LIME, & LIQUID ANTI-STRIPPING

AGENTS

402-1 to 402-7

403 OPEN-GRADED FRICTION COURSE (QC/QA) 403-1 to 403-4 404 OPEN GRADED FRICTION COURSE (NON QC/QA) 404-1 to 404-5 405 DETOUR PAVEMENTS 405-1 to 405-4 407 TACK COAT 407-1 to 407-2 408 PRIME COAT 408-1 to 408-3

412 HOT-IN-PLACE RECYCLING OF ASPHALT PAVEMENT (REMIXING

METHOD)

412-1 to 412-6

413 SINGLE-MACHINE HOT IN-PLACE SURFACE REPAVING 413-1 to 413-7 415 PAVEMENT SURFACE RESTORATION 415-1 to 415-8

420 PLANT-MIX BITUMINOUS PAVEMENT (DENSE-GRADED A,B,C,D, NON

QC/QA)

420-1 to 420-20

421 PLANT-MIX BITUMINOUS PAVEMENT (DENSE-GRADED A,B,C,D, QC/QA) 421-1 to 421-17 422 PLANT-MIX BITUMINOUS PAVEMENT (SUPERPAVE, NON QC/QA) 422-1 to 422-22 423 PLANT MIX BITUMINOUS PAVEMENT (SUPERPAVE QC/QA) 423-1 to 423-19 450 PORTLAND CEMENT CONCRETE PAVEMENT (QC/QA) 450-1 to 450-15

DIVISION 500 - STRUCTURES

501 DRIVEN BEARING PILES 501-1 to 501-18 502 DRILLED SHAFT CONCRETE BEARING PILES 502-1 to 502-19 506 MECHANICALLY STABILIZED EARTH RETAINING STRUCTURES 506-1 to 506-10 510 PORTLAND CEMENT CONCRETE 510-1 to 510-41 535 CRACK SEALING USING LOW-VISCOSITY GRAVITY-FED SEALERS 535-1 to 535-5

TABLE OF CONTENTS

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536 POLYMER CONCRETE BRIDGE DECK OVERLAY 536-1 to 536-9 540 STEEL REINFORCEMENT 540-1 to 540-13

DIVISION 600 - MISCELLANEOUS CONSTRUCTION

602 SLOPE AND EROSION PROTECTION STRUCTURES 602-1 to 602-12 604 SOIL AND DRAINAGE GEOTEXTILES 604-1 to 604-7 606 METAL AND CONCRETE WALL BARRIER 606-1 to 606-13

DIVISION 700 - TRAFFIC CONTROL DEVICES

701 TRAFFIC SIGNS AND SIGN STRUCTURES 701-1 to 701-22

DIVISION 900 - QUALITY CRITERIA

901 QUALITY CONTROL/QUALITY ASSURANCE (QC/QA) 901-1 to 901-19

920 EVALUATION OF PROPERTIES FOR PLANT-MIXED BITUMINOUS

PAVEMENT

920-1 to 920-4

SUPPLEMENTAL SPECIFICATIONS FOR

EXCAVATION, BORROW AND EMBANKMENT

SECTION 203

All provisions of the New Mexico Department Of Transportation's Standard Specifications for Highway and Bridge Construction shall apply in addition to the following:

Delete SECTION 203 - EXCAVATION, BORROW AND EMBANKMENT in its entirety and substitute the following:

203.1 DESCRIPTION.

203.11 This work shall consist of excavation, providing borrow, constructing embankment, hauling, disposing, placing, and compacting all materials in compliance with the specifications, and the lines, grades, thicknesses, and typical cross-sections shown in the contract.

203.2 MATERIALS.

Geotechnical investigation results are shown in the Contract Documents or are available from the Project Office. The geotechnical investigation is provided for information only. Information contained in the geotechnical investigation is not a representation or warranty of the continuity of the conditions identified beyond the test holes or test pits subsurface investigation. It is expressly understood that the Contractor is solely responsible for interpretations and conclusions drawn from this geotechnical information.

203.21 Classification of Materials. Material will be classified for payment as follows:

A. Rock Excavation. Rock excavation is defined as sound and solid masses, layers, or ledges of mineral matter in place and of such hardness and texture that it meets one of the following field test criteria:

1. Ripping Test. Materials which cannot be effectively loosened or broken down by ripping in a single pass with a late model, well-maintained tractor-mounted hydraulic ripper equipped with one digging point of standard manufacturer’s design adequately sized for use with, and propelled by, a crawler-type tractor with a minimum net flywheel power rating of 190 kW (255hp), operating in low gear will be classified as rock excavation; or

2. Seismic Test. The Contractor may elect to use seismic velocities performed by a person qualified to classify material. In this case, all materials with seismic velocities over 1800 m/s (6000 ft/s) will be classified as rock excavation. At least 14 days prior to performing the excavation work, the Contractor shall submit for

203-1 approval to the Project Manager the qualifications of the person performing and interpreting the seismic testing. However, in all cases, an Item 1 (crawler-type tractor ripper) will be used to resolve differences with regard to type of material, if velocities fall below 1800 m/s (6000 ft/s).

3. Handling Test. All boulders or detached pieces of solid rock more than 1 m3 (1.3 yd3) in volume which cannot be readily broken down with excavation equipment will be classified as rock excavation.

B. Unclassified Excavation. Unclassified excavation includes all material other than rock excavation. All boulders or detached pieces of solid rock less than 1 m3 (1.3 yd3) in volume will be classified as unclassified excavation.

C. Borrow. Borrow shall consist of approved material required for the construction of embankments, or for other portions of the work, and, unless otherwise defined in the contract, shall be obtained from contractor provided sources that have been approved by the Project Manager. Borrow shall be provided in accordance with the requirements of Section 203.34, below. R-values shall conform with the values shown in the contract.

D. Embankment. Embankment shall consist of constructing embankments and miscellaneous fill with suitable materials from unclassified excavation, borrow, and other sources.

E. Subexcavation. Subexcavation shall consist of excavating unsuitable and unstable material below established profile grade or typical cross-section to the dimensions shown on the plans, or as designated by the Project Manager. The removed materials shall be hauled and disposed of at the site(s) designated in the contract or as determined by the Project Manager. Voids created by subexcavation in roadbed areas shall be backfilled with approved material meeting the R-value requirements

203.3 CONSTRUCTION REQUIREMENTS.

203.31 General. Excavation and embankment for the roadway, intersections, and entrances shall be finished to reasonably smooth and uniform surfaces. No materials shall be wasted without prior approval by the Project Manager. Material with an R-value less than the design R-value shall not be placed, or be allowed to remain, within the top 600 mm (2 feet) of the finished subgrade. Excavation operations shall be conducted to preserve the materials below and beyond the lines and grades of all excavations in the soundest possible condition. Prior to beginning excavation, grading, and embankment operations in any area, all necessary clearing and grubbing shall be performed in accordance with Section 201, Clearing and Grubbing. The Contractor shall notify the Project Manager sufficiently in advance of opening excavation or borrow areas so that cross-section elevations and measurements of the ground surface may be taken.

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In the event the Contractor encounters a previously unreported environmental or cultural resource which is not included in the Contract, the Contractor shall terminate all further operations in the immediate area until the Department has had the opportunity to review and complete appropriate mitigation actions as required in subsection 107.12, Environmental and Cultural Resource Discoveries.

All excess or unsuitable excavated material, including rock and boulders that cannot be used in embankments, may be placed in the toe of any fill or may be used to flatten slopes of nearby fills. The work will be completed in a manner satisfactory tothe Project Manager. This will require that a minimum of 600 mm (2 ft) of cover soil placed over the rocks and boulders All excess material that cannot be used in embankments will be disposed in a manner suitable to the Project Manager and in conformance with environmental requirements.

203.32 Excavation. All roadbed earth cut sections shall be removed to subgrade elevation for the full width of the roadbed. Roadbed cut sections resulting from excavation shall be finished to a reasonably smooth and uniform surface. The Contractor shall remove unsuitable or unstable material below finished subgrade. The Contractor shall conduct removal operations of unsuitable material in such a way that the necessary cross-sectional measurements can be taken before the backfill is placed.

All removed material shall be disposed of as shown in the contract. Material will be considered unsuitable if it has an R-value that is less than the R-value designated in the contract, or if deleterious material is present, and will be considered unstable if saturated and pumping.

203.321 Limits of Excavation. All excavation shall be to the lines and grades shown in the drawings. Surveying during excavation, for excavation control purposes, shall be the responsibility of the Contractor. All quantities shall be measured and classified in place, to the lines shown on the drawings. The limits of material meeting the classification of rock excavation, as covered in subsection 203.21A paragraphs 1 Ripping Test or 2 Seismic Test, shall be determined by conducting either the ripping test or the seismic test at the boundaries of excavated material that will be classified as rock excavation and material that will be classified as unclassified excavation. The Department shall verify these tests. The limits of material to be classified as rock excavation must be agreed upon by both the contractor and the Project Manager prior to the material being excavated. As an alternative, the limits of rock excavation may be determined based on the estimated percentages shown in the contract as covered in subsection 203.41A. If material has been classified as rock excavation, as covered in subsection 203.21 A, Rock Excavation, paragraph 2 Seismic Test and such material is overlain by soil or overburden, the quantities for rock excavation shall be measured from the blaster’s drill hole log cards. Such log cards shall become a part of the surveying records supporting the computation of rock excavation quantities.

203.33 Rock Cuts. The Contractor shall be responsible for using proper drilling and blasting procedures in accordance with the criteria hereinafter described. Controlled blasting rock excavation will be in accordance with accepted practices and shall produce a clean face on the excavated cut which will be unaffected by subsequent

203-3 blasting and excavation operations. Unless otherwise provided, roadbed cuts in rock shall be excavated to subgrade elevation. A tolerance of 150 mm (6 in.) below the subgrade elevation will be permitted. Undrained pockets shall not be left on the roadbed surface. Base course shall be placed on the rock cut foundation and compacted to the required density. After compaction, the surfacing material shall be in compliance with the grade, elevation, and typical section shown in the contract.

203.331 Blasting Requirements. This provision concerns excavation of rock using controlled blasting to establish a specified backslope with minimal blast damage, and production blasting to facilitate excavation.

A. Definitions.

1. Controlled Blasting refers to the controlled use of explosives and blasting accessories in carefully spaced and aligned blast holes to provide a free surface or shear plane in the rock along the specified backslope; and to limit fly rock, permanent ground displacement, air concussion, and overbreak. Controlled blasting methods covered by this Specification include pre-splitting and cushion blasting.

2. Pre-Splitting is the simultaneous detonation of a single line of blast holes drilled along a specified excavation backslope before production blast holes are fired.

The spacing for pre-split blast holes is typically less than for production blast holes.

3. Cushion Blasting (also known as Trim Blasting) is the simultaneous detonation of a single line of blast holes along a specified excavation backslope after the main excavation has been completed. This method is performed to trim the excavation to the final backslope. The spacing for cushion blast holes is typically less than for production blast holes.

4. Production Blasting is fragmentation blasting in the main excavation area, usually using more widely spaced blast holes than are used for controlled blasting.

5. Final Line, or Controlled Blast Line refers to the row of controlled blast holes drilled in the plane of the specified excavation backslope. The controlled blast holes drilled in this plane constitute the basis for payment under the Controlled Blasting pay item. All blast holes drilled in front of the final line blast holes are considered to be production blast holes, which are incidental to the Rock Excavation pay item.

6. Buffer Row is the first row of production blast holes immediately adjacent to, and drilled in a plane parallel to, the controlled blast line. The explosive load in the buffer row should generally be reduced from standard production loads to minimize blast-induced damage to the final excavation backslope.

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7. Blasting Operations are all activities related to blasting, including but not restricted to collaring and drilling of blast holes; preparing, fixing, loading, and firing of explosive charges; assessment of the blast after detonation; and handling of misfires.

B. Submittals.

1. Blaster in Charge. At least 30 calendar days before the delivery or use of explosive material, the Contractor shall submit for approval the name and qualifications of the person authorized to act on behalf of the Contractor and who must be licensed by the applicable state and/or local regulatory agencies to possess, transport, and use explosives. The qualifications of the Blaster in Charge shall include a list of three or more blasting projects of similar complexity that were successfully completed within the preceding five years. References relating to these projects shall be provided. The Blaster in Charge shall be approved by the Project Manager prior to the beginning of any drilling or blasting work. The Blaster in Charge shall be on-site during all blasting operations.

2. Blasting Plans. The Contractor shall provide a General Blasting Plan for each cut that requires blasting. The General Blasting Plan shall include a description of the proposed blasting operation; preliminary design criteria for production and controlled blasting including blast hole depths and patterns; and details regarding explosives and blasting accessories that will be used. The general blasting plan shall be submitted to the Project Manager no less than two weeks prior to commencing drilling and blasting operations on the specified cut. At least 48 hours prior to an individual blast, the Contractor shall submit a Detailed Blasting Plan for the blast, which contains the full details of the drilling and blasting patterns and controls the Contractor proposes to use for controlled blasting and production blasting. The intent of the Detailed Blasting Plan is to document the details for individual blasts with respect to schedule, design parameters, and actual blast hole patterns. The Detailed Blasting Plan for an individual blast shall contain the following minimum information:

a. Station limits of the proposed shot, including bench elevation if appropriate.

b. Date and time that blasting will take place.

c. Removal of overburden, if applicable.

d. Plan and cross section diagrams of proposed drill pattern for controlled and production blast holes, including buffer rows, free face, burden, blast hole spacing, blast hole diameters, blast hole angles, lift height, and subdrill depth. Plans and cross sections shall be accurately drawn to scale.

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e. Loading diagram showing the type and amount of explosives, primers, and initiators; and the location, depth, and type of stemming.

f. Initiation sequence of controlled and production blast holes, including delay times and delay system.

g. Manufacturer’s data sheets for all explosives, primers, and initiators to be employed.

All blasting plans must be submitted to the Project Manager for review and approval by the Department. Any Department concerns will be discussed with the Contractor as quickly as possible. Any revisions to the blasting plans that are required based on the review by the Project Manager shall be submitted in writing to the Project Manager for final review and approval. Drilling and blasting operations related to a General Blasting Plan shall not proceed without prior written approval of the plan by the Project Manager. Loading of blast holes associated with a specific Detailed Blasting Plan shall not proceed without prior written approval of the plan by the Project Manager.

Although Blasting Plan submittals and approvals will allow for quality control and record keeping purposes, it remains the responsibility of the Contractor to execute the Contractor’s blasting operations according to the approved plans.

The Contractor shall cease blasting operations and submit revised blasting plans if it is determined that through the methods being employed, property beyond the right-of-way is being adversely impacted by the blasting operations.

3. Blasting Records. Each shot shall have a Blasting Record prepared and submitted by the Contractor on the day of the blast containing the following information:

a. Actual dimensions of the shot, including blast hole diameters and depths, burden, spacing, subdrilling depths, stemming, powder loads, powder factors, and timing.

b. A drawing or sketch showing direction of the face and physical shot layout.

c. Location of the blast in relation to project stationing and elevation.

d. Date and time of loading and detonation.

e. Name and signature of the person in responsible charge of loading and firing.

f. Comments by Blaster in Charge regarding misfires, fly rock occurrences, unusual results or effects; and damage to existing facilities, adjacent property, or completed work.

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g. Vibration and blast monitoring results.

h. Any complaints received due to the blasting.

C. Explosives. Whenever explosives are used, they shall be of the character and amounts as permitted by State and local laws and ordinances, and all the requirements established by respective agencies having jurisdiction over them. The transportation, storage, handling, and use of explosives shall be in accordance with applicable federal, state, and local laws and regulations. All explosives and accessory devices shall be from a recognized supplier, and shall be products of a company regularly engaged in the manufacture of explosives and related products.

The handling and use of explosives and accessory devices shall be in accordance with the instructions of the manufacturers. Products with an expired shelf life shall not be used.

The federal agencies administering regulations that involve explosive material are the Bureau of Alcohol, Tobacco, and Firearms (ATF), U.S. Department of Transportation (DOT), and the Occupational Safety and Health Administration (OSHA). State and local agencies include the Fire Marshal, Sheriff, and others.

Specific basic authority (Code of Regulations) and responsibility definitions include:

1. ATF – Storage and accountability (record keeping and security) as prescribed in

27 CFR Part55.

2. OSHA – Transportation, worker safety and health as prescribed in 29 CFR;

storage and unsafe blasting practices in handling and use as prescribed in Part 1926, Subpart U (1926.900); Use and Loading of Explosives into Blast holes.

3. DOT – Transportation and public safety.

D. Safety. General safe practices that shall be followed by the Contractor include:

1. Federal, state, and local regulations pertaining to the transportation, storage, and use of explosives must be strictly followed.

2. When required, a blasting permit must be obtained from the local regulatory agency by the Blaster in Charge to conduct the intended blasting.

3. Only persons authorized and qualified based on training and experience shall be allowed to handle and use explosives.

4. No person shall smoke, carry matches or other flame producing devices, nor shall firearms or loaded cartridges be carried while in or near a motor vehicle transporting explosives.

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5. All explosives must be accounted for at all times. Explosives not being used must be stored in a locked, approved magazine facility required under the applicable provisions of DOT, ATF, and OSHA.

6. The Contractor shall post all required areas and vehicles with appropriate signs, as required by federal regulations.

7. Necessary guards or flag persons must be safely stationed on highways during blasting to control highway traffic.

8. The Contractor shall observe the entire blast area for a minimum of five (5) minutes following each blast before commencing work in the cut. Potentially dangerous boulders or other material located beyond the excavation limits shall be removed by the Contractor. The Contractor shall cease blasting operations if it is determined that the required slopes are not being obtained in a stable condition, or if the safety and convenience of the traveling public are being jeopardized.

E. Pre-Blast Survey. For each cut that requires blasting, the Contractor shall perform a pre-blast survey of nearby buildings, structures, utilities, water supplies, or other environmentally sensitive areas which may potentially be at risk from blasting damage. The pre-blast condition survey shall be performed in accordance with SECTION 617-VIBRATION MONITORING. The Contractor shall certify to the Project Manager in writing prior to drilling blast holes that the pre-blast survey for a specified cut has been completed.

The Contractor, prior to the commencement of blasting, shall notify adjacent property owners and occupants of local buildings. The Contractor shall be responsible for damages resulting from blasting.

F. Blasting Test Sections. The adequacy of each proposed Blasting Plan shall be demonstrated by means of Blasting Test Section(s) when material of different geologic characteristic is encountered. For projects involving multiple cuts in similar geologic materials, the requirement for a Blasting Test Section in each cut may be reduced upon concurrence by the Project Manager. Blasting Test Sections shall include drilling, blasting, and excavating cut sections approximately 30 m (100 ft) long, to determine the optimum combination of method, blast hole spacing, and charge. When field conditions warrant, the Contractor may be directed to use test section lengths less than 30 m (100 ft) long. Requirements of the Blasting Test Sections shall include the following:

1. The Blasting Test Section shall be accomplished in accordance with all requirements of Section 203.331, Blasting Requirements. A Detailed Blasting Plan for the test section shall be prepared by the Contractor, and submitted to the Project Manager at least 48 hours prior to the planned time of the blast. This Plan must be approved by the Project Manager prior to blasting the test section.

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The Contractor shall begin the tests with the controlled blast holes spaced at 0.75-meters (30 inches) unless the Contractor’s Blasting Plan indicates otherwise.

. Following blasting, a sufficient amount of material shall be removed from the test section so that it can be determined if the blast hole diameter, blast hole spacing, and amount of explosives are adequate to provide the required backslope. The Contractor shall not drill ahead of the test section area until the test section has been excavated and the adequacy of results evaluated.

If at any time during the progress of the main blasting operation the methods of drilling and blasting do not produce the desired results, the Contractor shall revise and retest the blasting techniques until a technique is developed that will produce the required results. The results will be considered unsatisfactory if:

a. There is an excessive amount of breakage beyond the indicated lines and grade.

b. There is excessive flyrock.

c. The final backslope within the tolerances specified is non-uniform.

d. Ground vibration and air blast levels exceed limits as covered in subsection 203.331G(2), Mitigation and Monitoring.

e. There are violations of other requirements of the specifications.

f. Slopes are unstable.

g. Safety of the public is jeopardized.

h. Property or natural features are endangered.

G. Blasting Execution.

1. Notification and Schedule.

a. The Contractor shall coordinate blasting operations with the Project Manager, and notify the Project Manager a minimum of 1.5 hours prior to the blast. The time of the blast shall be estimated within a one-hour timeframe. For example, the contactor shall notify the Project Manager by 0900 hours of a blast scheduled between 1030 and 1130 hours.

b. Subject to permit provisions, the Contractor shall notify required federal, state, and local agencies prior to each blast, or provide these agencies a blasting schedule.

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c. Occupants of buildings and owners of structures and utilities that have been identified in the pre-blast survey shall be notified a minimum of 48 hours before drilling or blasting begins. Notification shall include the location and intended time of blasting.

d. Once the blast is tied in, it shall be detonated at the planned time, unless approved otherwise by the Project Manager.

2. Mitigation and Monitoring.

a. Vibration Control and Monitoring. The Contractor shall perform vibration control and monitoring of areas identified by the pre-blast survey as described in SECTION 617 VIBRATION MONITORING.

b. Air Blast and Noise Control. The Contractor shall maintain air blast and noise control in areas identified by the pre-blast survey as described in

SECTION 617 VIBRATION MONITORING.

c. Flyrock Control. Before the firing of blasts in areas where flying rock may result in personal injury or unacceptable damage to property or the work, the rock to be blasted shall be covered with blasting mats, soil, or other equally serviceable material, to limit flyrock from the blast area.

3. Controlled Blasting Requirements. Controlled blasting shall be carried out in accordance with the Detailed Blasting Plans that produced acceptable results in Blasting Test Sections. The following requirements shall apply to both pre-splitting and cushion blasting:

a. If the overburden is of such nature and material that it will not support drill holes, the Contractor shall completely remove all overburden soil and loose rock along the top of the cut to expose the rock surface prior to drilling the controlled blast holes.

b. Controlled blast holes shall be verified with functioning mechanical devices to determine the angle at which the drill steel enters the rock.

Controlled blast hole drilling will not be permitted if these devices are inoperative.

c. The Contractor shall drill 50-mm to 75-mm (2-in. to 3-in.) nominal diameter blast holes at such spacing center to center, as determined by Blasting Test Sections or satisfactory results achieved in similar geologic materials, to achieve acceptable results, but in no case shall the spacing exceed 1 m (3 ft.).

d. The Contractor shall control drilling operations by the use of the proper equipment and technique to ensure that no blast holes deviate from the plane of the planned construction backslope by more than 200 mm (8 in.)

203-10 either parallel or normal to the slope. Blast holes exceeding these limits shall not be paid for unless, in the opinion of the Project Manager, satisfactory slopes are being obtained.

e. The controlled blast holes shall be drilled on the controlled blast line at the required slope inclination, to the full depth of the cut, or to a pre-determined stage elevation. The height of any individual lift shall not exceed 10 m (33 ft), and shall be less than 10 m (33 ft) if the Project Manager considers that the tolerance in directional control is inadequate.

If greater than 5 percent of the controlled blast holes are misaligned in any one lift, the Contractor shall reduce the height of the lifts until the 200 mm (8-inch) tolerance is met. Upon satisfactory demonstration of directional control and blast results, the length of controlled blast holes may be incrementally increased only with written approval of the Project Manager.

f. Unloaded and un-stemmed guide holes, when used between loaded controlled blast holes, shall be of the same diameter, drilled in the same plane, and drilled to the same tolerance as controlled blast holes.

g. When the cut height will require more than one lift, a maximum offset of

600 mm (24 in.) at the bottom of each lift shall be permitted to allow for drill equipment clearances. The Contractor shall begin the control blast hole drilling at a point which will allow for necessary offsets, and shall adjust at the start of lower lifts as necessary to compensate for any drift which may have occurred in the upper lifts.

h. The use of horizontal blast holes for controlled blasting is prohibited.

i. Explosive charges, detonating cord, and other items necessary for the blasting operation shall be in accordance with the explosive manufacturer’s recommendations and instructions, and shall be the full responsibility of the Contractor.

j. Before placing charges, the Contractor shall determine that the hole is free of obstructions for its entire depth. All necessary precautions, including the use of PVC casing if required, shall be exercised so that the placing of the charges will not cause caving of material from the walls of the holes.

k. Only standard explosives manufactured especially for the appropriate type of controlled blasting (cushion or pre-splitting) shall be used in controlled blast holes, unless otherwise approved by the Project Manager.

Ammonium nitrate and fuel oil (ANFO) shall not be loaded in the controlled blast holes. Blast hole conditions may vary from dry to filled with water, and the Contractor shall be required to use explosives and blasting accessories that are necessary to achieve satisfactory results.

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l. Continuous column cartridge-type explosives used with detonating cord shall be assembled and affixed to the detonating cord in accordance with the explosive manufacturers instructions, a copy of which shall be provided to the Project Manager.

m. The bottom charge of a controlled blast hole may be larger than the charges above, but shall not be large enough to cause overbreak. The top charge in a controlled blast hole shall be placed far enough below the collar, and reduced sufficiently, to avoid overbreaking or heaving.

n. The upper portion of all controlled blast holes, from the top charge to the hole collar, shall be stemmed. Stemming materials shall be a dry, angular, and granular material, all of which passes a 9.5 mm (3/8-inch) sieve.

4. Pre-Split Blasting. If pre-split blasting is approved, the following shall apply in addition to the provisions of Section 203.331, Subsection G3, Controlled Blasting:

a. As long as equally satisfactory slopes are obtained, the Contractor may either detonate the pre-split blast holes before drilling for production blasting, or detonate the pre-split blast holes and production holes in the same blast, provided that the pre-split blast holes are fired first.

b. When fired with the main production blast, the pre-split blast holes shall be detonated at least 75 milliseconds before production blast holes.

c. Pre-split blast holes shall generally be detonated simultaneously.

However, if required to reduce ground vibrations, noise, or air blast, pre-split blast holes may be delayed in sections to reduce the charge weight per delay.

d. The line of pre-split blast holes shall extend beyond the limits of the production blast holes to be detonated. The minimum length of this extension shall be 10 m (33 ft), or to the end of the cut; but shall not be greater than ½ of the distance of the expected blast advance.

e. In no case will pre-split blasting be allowed where the controlled blast line to free face distance is less than 6 m (20 ft) or less than 3 times the blast hole depth, whichever is greater.

5. Cushion Blasting. If cushion blasting is approved, the following shall apply, in addition to the provisions of Section 203.331, Subsection G3, Controlled Blasting:

a. Cushion blast holes shall be detonated as part of a final shot, after all other blasting on a lift or other excavation has taken place.

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b. If production blast holes are included in the final shot, cushion blast holes shall be detonated last. The difference in delay time between the cushion blast line and the buffer row shall not be greater than 75 milliseconds nor less than 25 milliseconds.

c. The cushion blast holes shall be detonated simultaneously, or in sections subject to charge weight per delay limitations for vibration, noise, or air blast control.

6. Production Blasting. Production blasting shall be carried out in accordance with the Blasting Plan that produced acceptable results in Blasting Test Sections.

The following requirements shall apply to production blasting:

a. The Contractor shall take all necessary precautions in production blasting so as to minimize blast damage to the final excavation backslope.

b. The buffer row of production blast holes shall be drilled on a plane approximately parallel to the controlled blast line.

c. The buffer row of production blast holes shall be no closer than 2 m (6 ft) to the controlled blast line, unless the Contractor can demonstrate that the final excavation backslope will not be damaged by the production blast, and approved by the Project Manager.

d. Where necessary to minimize damage to the excavation backslope, blast holes in the buffer row shall be loaded lighter than other production holes.

e. Except in the lower-most lift, the bottom of production blast holes shall not be lower than the bottom of controlled blast holes.

f. Production blast holes shall not exceed 150 mm (6 in.) in diameter, unless otherwise approved by the Project Manager.

g. Before placing charges, the Contractor shall determine that the blast holes are free of obstructions for the entire depth. All necessary precautions, including PVC casing if required, shall be exercised so that placing of charges will not cause caving of material from blast hole sidewalls.

h. Stemming material used in production blast holes shall be a dry, angular, and granular material, all of which passes a 9.5 mm (3/8-inch) sieve.

i. Production blast holes shall be detonated in a controlled delay sequence toward a free face.

j. The use of horizontal blast holes for production blasting is prohibited, except for equipment access.

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k. Blast hole conditions may vary from dry to wet, and the Contractor shall be required to use explosives and blasting accessories that are necessary to achieve satisfactory results.

7. Scaling and Stabilization of Slopes Established by Controlled Blasting.

a. The Contractor shall observe the entire blast area following a blast before commencing work in the cut. Any rocks considered by the Project Manager to be loose, hanging, or potentially dangerous within a blast area, or other material located beyond the excavation limits shall be removed by the Contractor. Drilling of the next round will not be allowed until this work has been completed, unless approved by the Project Manager.

b. Slopes established by controlled blasting shall be scaled throughout the span of the contract and at such frequency as required to remove all hazardous loose rock or overhangs. The slopes shall be hand scaled using a suitable standard steel mine scaling rod. Subject to the Project Manager’s approval, other methods such as machine scaling, hydraulic splitters, or light blasting may be used in lieu of or to supplement hand scaling. Payment for scaling of excavation backslopes established by controlled blasting shall be incidental to the contract unit price for Rock Excavation.

c. If in-place stabilization is required, as determined by the Project Manager, rock bolting or other approved stabilization techniques will be used.

Stabilization necessitated by the geologic conditions, will be paid for at the appropriate unit price. Stabilization necessitated by the Contractor’s blasting operations, shall be performed at the Contractor’s expense.

d. The Contractor shall cease blasting operations if it is determined by the

Project Manager that the required slopes are not being obtained in a stable condition, or if the safety and convenience of the traveling public are being jeopardized. Results will be considered unsatisfactory if:

1. There is an excessive amount of breakage beyond the indicated lines and grade.

2. There is excessive flyrock.

3. The final backslope within the tolerances specified are non-uniform.

4. Ground vibration and air blast levels exceed limits as covered in subsection 203.331G(2), Mitigation and Monitoring.

5. There are violations of other requirements of the specifications.

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6. Slopes are unstable.

7. The safety of the public is jeopardized.

8. Property or natural features are endangered.

203.34 Borrow. Unless otherwise specified in the Contract, the Contractor will obtain its own borrow source. Unless otherwise approved by the Project Manager, borrow material in any area will not be placed until after the unclassified excavation has been utilized for embankment in that area. If the Contractor places more borrow than is required and thereby causes a waste of excavation, the amount of the waste will be deducted from the borrow volume as measured in the borrow area. All borrow areas which are to be measured for payment by cross-sectioning shall be bladed and left in such shape as to permit accurate measurements after excavation has been completed.

The Contractor shall not remove borrow beyond the dimensions and elevations established, and no material shall be removed prior to the surveying the site. The finished borrow areas shall be approximately true to the established line and grade.

When it is necessary to remove fencing in connection with borrow operations, the fencing shall be replaced in as good or better condition than it was originally. The Contractor shall be responsible for the confinement of livestock when a portion of fence is removed. All unsuitable material shall be disposed of as shown in the contract or as directed by the Project Manager.

203.35 Embankments. Embankment material shall not be placed on frozen earth, nor shall frozen soils be placed in any embankments. Embankment construction shall be suspended when embankment materials become frozen, and construction operations shall not be resumed until the materials are thoroughly thawed and sufficiently dried for satisfactory compaction. Prior to beginning embankment construction, scalping shall be accomplished in accordance with Section 201, Clearing and Grubbing. When embankment is to be placed and compacted on hillsides, when new embankment is to be compacted against existing embankments, or when embankment is built one-half width at a time, the slopes that are steeper than one vertical to four horizontal, when measured at right angles to the roadway, shall be continuously benched as the work is brought up in layers. The exceptions are solid rock or as otherwise noted in the contract. Benching shall be of sufficient width to permit operation of placing and compacting equipment, and the additional excavation required will not be measured or paid for. Material thus cut out shall be recompacted along with the new embankment material at the Contractor’s expense. Rock, broken concrete, or other solid materials shall not be placed in embankment areas where driven piling or drilled caissons are to be constructed, or where a utility line or other structure is to be placed.

A. Roadbed Embankments. Where a roadbed embankment to be constructed is 1.20 m

(4 ft) or less in height, the original ground surface shall be completely broken up by plowing, scarifying, or stepping up to a minimum depth of 150 mm (6 in.). This area shall then be compacted to 95% of maximum density. The existing ground under pipe culvert bedding shall be broken up and compacted as herein provided, 203-15 regardless of embankment height. Roadbed embankment of earth material shall be placed in horizontal layers not exceeding 200 mm (8 in.), loose measurement, and shall be compacted in accordance with subsection 203.37, Moisture and Density Control. Where embankment is to be constructed across swampy ground that will not support the weight of trucks or other hauling equipment, the lower part of the fill may be constructed by placing an approved geotextile separating/reinforcing fabric directly on the natural ground. Trucks or other hauling equipment may be supported while placing subsequent layers by end dumping successive loads of approved granular material in a uniformly distributed layer not to exceed 600 mm (24 in.) in thickness. Construction of embankment across swampy ground shall be initiated only after written approval from the Geotechnical Section. The approval will be contingent on an investigation of the swampy ground and approval of the material to be used in the construction of the embankment. Spreading equipment shall be used on each layer to obtain reasonably uniform thickness prior to compacting. As the compaction of each layer progresses, necessary manipulation shall be accomplished to assure uniformity of density. Construction equipment shall be routed uniformly over the entire surface of each layer. Each layer of embankment shall be properly compacted before the next layer is started.

When the embankment material consists predominantly of rock fragments of such size that the material cannot be placed in layers of the thickness prescribed without crushing, pulverizing or further breaking down the pieces resulting from excavation, such material containing more than 25% of rock larger than 150 mm (6 in.) in diameter shall be placed in layers of sufficient depth to contain the maximum size rock in the material. In no case shall the thickness of the layers exceed 1 m (3 ft) before compacting, except that individual rocks or boulders of a size not exceeding 1 m (3 ft) in the greatest dimension will be permitted, provided they are distributed and the interstices filled to form a dense, compact mass. If the interstices between the rock fragments are not completely filled, the Contractor shall construct a bridge over the top of the rock fragments to prevent the overlying embankment material from filling the interstices. Rock fragments which may degrade with time or be water sensitive such as shale or gypsum, shall not be utilized as rock fill within any portion of roadway embankments. Such material shall be considered waste material.

Suitable material shall be used to replace rock waste material.

The Contractor shall submit a bridging plan to the Project Manager for review and approval a minimum of two weeks prior to the proposed construction of the bridging material. The plan shall include, as a minimum, a suitable geotextile separator/reinforcing fabric placed directly on top of the rock fragment layer, followed by 300 mm to 1.0 m (1 ft to 3 ft) of a fine grained compacted layer of suitable borrow material. Another acceptable separator/reinforcing fabric shall be placed directly on top of the compacted borrow, followed by placing a non-rock fragment embankment material. The bridging material shall cover the entire rock fragment area.

Placement of large boulders in the toe of the slope is acceptable based on the following limitations:

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1. Size of boulders is limited to 1/2 the embankment height with a maximum size of 3 m (10 ft).

2. Large boulders may be placed when the minimum height of fill is 2.5 m (8 ft) measured at the edge of the roadway shoulder.

3. Boulders shall be placed inside a line 150 mm (6 in.) from the slope stake and spaced a minimum of 1 m (3 ft) edge to edge. All boulders within this line shall be covered with specification embankment material.

4. Boulders greater than 1 m (3 ft) in any dimension shall not be placed in the roadway prism between the outermost edges of the outside shoulders.

Rock embankments shall be constructed to subgrade elevation and a tolerance of 150 mm (6 in.) below subgrade elevation will be permitted. When the embankment is a rock foundation, the subbase or base course material shall be compacted to the required density. After compaction the surfacing material shall be in substantial compliance with the grade, depth and typical section shown on the plans for the type of material placed. Rock fills shall be consolidated by the use of appropriate equipment and watered where necessary to obtain proper consolidation. If embankment can be placed only on one side of abutments, center walls, piers, or culvert headwalls care shall be taken that the area immediately adjacent to the structure is not compacted to the extent that it will cause overturning of, or excessive pressure against, the structure. When noted in the contract, the fill adjacent to the bent of a bridge shall not be placed higher than the bottom of the back wall of the bent until the superstructure is in place. When embankment is to be placed on both sides of a concrete wall or box-type structure, operations shall be so conducted that the embankment is always at approximately the same elevation on both sides of the structure.

B. Non-Roadbed Embankments. Non-roadbed embankments of earth material

(including but not necessary limited to dikes, etc.), shall be placed in horizontal layers and compacted uniformly over the entire surface of each layer in accordance with subsection 203.37, Moisture and Density Control, unless otherwise provided in the contract. When the embankment material consists of rock it shall be placed in layers of sufficient depth to contain the maximum size rock in the material, provided it is carefully distributed and the interstices filled to form a dense mass.

Non-roadbed rock embankments may be constructed by end dumping, or casting, providing rock is covered and uniformly dressed. When non-roadbed embankment is to be placed on hillsides, when such embankment is to be constructed against existing embankments, or when such embankment is built one-half width at a time, the slopes that are steeper than one vertical to four horizontal, when measured at right angles to the centerline of the embankment, shall, except in solid rock, be continuously benched over those areas where it is required as the work is brought up in layers. Benching shall be of sufficient width to permit operation of equipment, and the excavation required will not be measured or paid for.

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203.36 Subexcavation. When called for in the contract or required by the Project Manager, the Contractor shall remove unsuitable and unstable materials from the subgrade. B ackfill with approved materials to the finished graded sections shall be done in such a way that the Project Manager can take the necessary cross-sectional measurements before the backfill is placed. All removed materials shall be disposed of as shown in the contract or as directed by the Project Manager. The Contractor shall backfill the subexcavated section back to the finished graded section with the appropriate material.

203.37 Moisture and Density Control. Unless otherwise provided in the contract, or as noted below (rock embankments), roadbed, roadbed embankment, non-roadbed embankment, and roadway median excavation or embankment, shall be constructed with moisture and density control. Each layer of embankment shall be compacted to not less than 95% of maximum density, except the top 150 mm (6 in.) of the roadbed shall be constructed in accordance with Section 207, Subgrade Preparation. Unless otherwise provided in the contract, the moisture content of the soil at the time of compaction shall not exceed the optimum or be less than the optimum minus five percentage points as determined by AASHTO T 224 and AASHTO T 99, Method C, except that soils subject to high volume changes may require moisture contents in excess of the optimum, if approved by the Project Manager. For all soils with a plasticity index of 15 or greater, the moisture content of the soil at the time of compaction shall be in the range of optimum minus 1% to optimum plus 4%. If the moisture content at the time of compaction is not within the specified range, the material shall be either moistened or dried and thoroughly mixed by reprocessing, to the full depth of the lift, before recompaction. Construction of roadbed embankments predominantly of rock or coarse grained material (65% or greater retained on the 4.75-mm (No. 4) sieve) will not require moisture and density control, except that the top 150 mm (6 in.) of the embankment shall be constructed in accordance with the requirements of subsection 207.3, Construction Requirements. Construction of non-roadbed embankments of rock material will not require moisture and density control unless otherwise specified. Maximum densities will be determined by AASHTO T 224 and AASHTO T 99, Method C, and field densities will be determined by AASHTO T 205, use of nuclear methods in conformity with AASHTO T 238 and T 239, or other approved methods. Densities shall be taken at each lift just prior to each succeeding lift.

203.4 METHOD OF MEASUREMENT.

203.41 Measurement will be made as follows:

Rock excavation will be measured by the cubic meter (cubic yard).

Unclassified excavation will be measured by the cubic meter (cubic yard).

Borrow will be measured by the cubic meter (cubic yard)…