This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
PAVEMENT DESIGN SUMMARY AND MATERIALS DESIGN REPORT
Appendices Appendix A – Materials Design Report Appendix B – DARWin Pavement Analysis Printouts Appendix C – R-value Calculation Spreadsheet Appendix D – ESAL Calculations
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2 1
1. INTRODUCTION
This report presents the results of our pavement design for the proposed improvements to SR 83,
roughly between Mile Post 46.64 and Mile Post 47.13 in Pima County, Arizona, for the design
and construction of the proposed T-Intersection project. The planned improvement is to construct
a T-Intersection with associated turn and travel lanes. This T-Intersection will provide permanent
access to the Rosemont Copper Project (mine) via a Primary Access Road. Therefore, the
existing SR 83 will need to carry additional heavy truck traffic associated with the mine. The
objectives of this geotechnical evaluation included:
• Evaluation of the existing SR 83 pavement and geotechnical conditions within the project limits,
• Providing recommendations for the new T-Intersection pavement structural sections; and
• Providing recommendations relative to the geotechnical aspects for the planned improvements.
For brevity, this report does not include explanations of field activities, discussion of laboratory
tests performed, or an evaluation of the geological setting and hazards. These items are presented
in the Geotechnical Evaluation Report for this project, which has been submitted separately.
2. SCOPE OF SERVICES
The scope of services for this project generally included:
• Conducting research into previously prepared reports and as-built plans for the SR 83 section under study.
• Preparing a drilling plan and associated permit application for submittal to Arizona Department of Transportation (ADOT) Permits.
• Conducting a field reconnaissance of the project alignment to mark out proposed exploration locations in the field and to visually evaluate the pavement condition. Arizona Blue Stake was notified of the proposed boring locations prior to excavating.
• Arranging for appropriate traffic control measures.
• Performing a field exploration consisting of:
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2 2
Pavement coring and subgrade soil borings at four (4) locations (C-1 through C-4) on the SR 83 c/oexisting pavement.
Slope borings advanced at nine (9) locations (B-1 through B-9) along the project alignment to depths ranging between 2.5 and 14.8 feet bgs. A Ninyo & Moore employee observed the drilling fieldwork and logged the borings. Each boring was backfilled with drilling spoils. The borings within the existing pavement were patched with cold asphaltic patch. Representative samples were collected in the field and returned to a Ninyo & Moore laboratory for further analysis and testing.
• Conducting laboratory tests of representative samples for developing parameters for pavement design and earthwork factors during construction. Testing generally included in-situ moisture content and dry density, gradation analysis, No. 200 sieve analysis, Atterberg limits, maximum density/optimum moisture relationship, consolidation (response to wetting), R-value, and corrosivity characteristics (including pH, minimum electrical resistivity, soluble sulfates, and chlorides).
• Preparing a Geotechnical Evaluation Report that presents our findings, conclusions, and geotechnical recommendations. This report is provided under separate cover.
• Preparing this Pavement Design Summary and Materials Design Report, presenting new structural pavement sections.
3. SITE DESCRIPTION
The proposed project site is located southeast of Tucson in Pima County, Arizona, on SR 83
roughly between Mile Post 46.64 and Mile Post 47.13 (approximately 11 miles south of Exit 281
on Interstate 10). This reach of SR 83 generally passes through a rural mountainous region
comprised of desert and high desert topography. The average project elevation is 4,486 feet
Mean Sea Level (MSL) with a slope from the west down to the east. A large incised drainage is
present along the east side of the road in this area. Land use within the study limits surrounding
SR 83 is primarily undeveloped. The existing undivided roadway is comprised of one-lane in
each direction of travel, generally in a southwest to northeast direction in the project vicinity.
The cut and fill slopes along the existing SR 83 roadway are up to approximately 15 feet in
relative height and inclination varying typically between 1.5:1 (Horizontal:Vertical) and 3:1, and
flatter. The existing cut slope faces exposed sand and gravel deposits, with variable weak to
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2 3
moderate cementation. Some signs of surficial erosion were visible; however, the existing slopes
appear to remain generally stable. No evidence of slope instability was observed.
4. PROJECT DESCRIPTION
Rosemont Copper Company (Rosemont) plans to construct a T-Intersection at SR 83 near MP
46.82 with associated turn and travel lanes. This T-Intersection will provide permanent access to
the Rosemont Copper Mine via a Primary Access Road. Therefore, the existing SR 83 will need
to be improved to accommodate the additional lanes and truck traffic associated with the mine.
The existing SR 83 2-lane roadway associated with the new T-intersection project will be
reconstructed within the project limits to include 1) a northbound left turn lane, 2) a southbound
right turn lane, and 3) a merging northbound acceleration lane.
New cuts and fills associated with this project will generally be up to about 15 feet in total height
with 2:1 (H:V) or flatter slopes. In addition, the project will include installation of a cattle guard
on the T-Intersection and the removal and replacement of a corrugated metal pipe (CMP) culvert
at Station 187+00.
It is anticipated that the existing SR 83 pavement will be removed within the project limits. New
pavement structural sections will include a Portland cement concrete (PCCP) and asphaltic
concrete (AC). The PCCP will be utilized approximately 100 to 200 feet north and south of the
T-intersection along SR 83 as well as for the access road turnout to the cattle guard. The AC
pavement will be placed on the remainder of the SR83 project alignment, including the access
road turnout from the cattle guard to the right-of-way boundary. An outside shoulder treatment
will be provided along the PCCP section.
The project will also include a turnout connecting to a Forest Service unpaved roadway and
temporary pavement for traffic control purposes during construction.
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2 4
5. DESIGN R-VALUE
The subsurface soils encountered in the borings consisted mainly of silty sand, clayey sand, or
clayey gravel. Occasional weak to moderate cementation was also encountered at some
locations. Table 1 below summarizes the laboratory and correlated R-values as measured by
Ninyo & Moore on soil samples obtained within the upper 2.5 to 5 feet below the existing
Based on the procedure for calculating the mean R-value outlined in the ADOT Preliminary
Engineering and Design Manual (PEDM), a mean R-value (Rmean) of 30 was calculated. A
calculation spreadsheet, which includes the test results, is included as Appendix C of this report.
For the pavement design, an R-value of 30 was used. For construction control, an R-value of 24
was used. For purposes of construction, it is assumed that soils placed within 3 feet of the
finished roadway subgrade will exhibit a construction control R-value of 24 or more.
In order to provide a relatively consistent subgrade base for construction, it is recommended that
the subgrade soils be scarified to a depth of 10 inches or more, moisture conditioned to a
moisture content generally near the optimum and re-compacted to 95 percent or more relative
compaction, in accordance with ASTM D 698. Subgrade soils should not contain organic matter
and should meet the project specifications as noted in the Geotechnical Evaluation Report dated
April 11, 2012. Subgrade soils within 3 feet of finish subgrade should have a construction control
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2 5
R-value of 24 or more. Improvement may be needed if the exposed subgrade material does not
meet the requirements of the Subgrade Acceptance Chart provided in the Materials Design
Report (Appendix A).
Unacceptable pavement subgrade soils, if encountered during construction, can be improved by
over excavating the soils to a depth of 3 feet or more below the bottom of the base layer, and
replacing with adequately moisture-conditioned and compacted engineered fill with an R-value
of 24 or more.
6. PAVEMENT DESIGN RECOMMENDATIONS
The following sections present the design parameters and recommendations for new pavements
within the project limits. It is recommended that the pavement sections provided in Table 2 be
used for pavement improvements associated with this project.
Table 2 – Pavement Section Summary
Pavement Section
Cement Treated
Subgrade
AC – Miscellaneous
Structural (Special Mix)
PCCP Fog
Coat
Chip
Seal
Coat
AB-Class 2
Aggregate Subbase-Class 6
Total Thickness
Section No. 1 (AC) - 6 - Yes Yes 5 - 11
Optional Section No. 1 (AC)* 6 4 - Yes Yes 4 - 14
Section No. 2 (PCCP) - - 9 - - 4 - 13
Outside Shoulder Treatment
- - - - - - varies varies
Turnout** - 2 - Yes - 4 - 6
Temporary Pavement*** - 2.5 - - - 5 - 7.5
* Optional pavement structural section, not included in Appendix A – Materials Design Report. **Typical Turnout pavement section to be used for this project. ** *For traffic control purposes.
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2 6
7. CHECK OF PAVEMENT DESIGN SECTION
The pavement sections recommended above are based on the design R-value, available traffic
count information, and the pavement design procedures outlined in the PEDM. The sections,
tables, or figures referenced by the procedure are included in the PEDM. Printouts of the analysis
performed using DARWin software are presented in Appendix B.
7.1. Traffic Volumes and Truck Factor Growth Rates
The traffic loading data were provided in a letter entitled ESAL Calculations to Support the
Pavement Design Memorandum, prepared by PSOMAS, dated September 15, 2011 (see
Appendix D). The design equivalent single axle loads (ESAL’s) for the pavement design
period is 1,836,447, as provided in the letter. For the temporary pavement, the traffic loading
was assumed based on the 6-month period of operation in the year 2012. For conservatism,
the anticipated ESAL’s were estimated for the Rosemont mine scenario. Table 3 summarizes
the design equivalent single axle loads (ESAL’s) for the roadways under consideration.
Table 3 – Traffic Loading Summary
Roadway Segment Approximate Design ESAL’s
SR 83 1,836,447 Temporary Pavement 40,331
7.2. Resilient Modulus
As discussed previously, a design R-value of 30 was utilized in the analysis of new
pavement sections. Based on an R-value of 30 and a seasonal variation factor of 2.2 taken
from Figure 202.02-1 in the PEDM, a resilient modulus of 11,138 pounds per square inch
(psi) was calculated.
7.3. Drainage Coefficient
A drainage coefficient of 0.92 was obtained from Table 202.02-7 in the PEDM, based on a
seasonal variation factor of 2.2 and fair drainage conditions.
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2 7
7.4. Serviceability
An initial serviceability of 4.1 and a terminal serviceability of 2.6 were used for the design
of the new pavement sections. The resulting serviceability index loss is 1.5.
7.5. Standard Deviation and Level of Reliability
A standard deviation of 0.25 and 0.35 was used for the design of the PCCP and AC
pavement, respectively. A level of reliability of 90 percent was utilized for the design. A
standard normal deviation (ZR) value of -1.282 was utilized for 90 percent reliability.
7.6. Modulus of Subgrade Reaction
Using the resilient modulus obtained above, and Figures 202.03-1, 202.03-2, and Table
202.03-2, the recommended modulus of subgrade reaction, k, is 230 pounds per cubic inch.
7.7. J Factor
A load transfer coefficient of 3.9, obtained from Table 202.03-1, was utilized in the design of
the PCCP section.
8. STRUCTURAL NUMBER SUMMARY – AC PAVEMENT
In accordance with the AASHTO procedure for flexible pavement design, and using the
parameters presented in Section 7, the minimum needed structural number (SN) for new AC
pavement section was calculated. Table 4 presents a summary of the required and design
structural numbers.
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2 8
Table 4 – Structural Number Summary – New AC Pavement Sections
Pavement Section Subgrade Minimum Required
Structural Number Structural Number of Recommended Section
Untreated 3.21 3.23 New AC Pavement Section
No. 1 Cement Stabilized 3.21 3.55
Temporary Pavement Untreated 1.66 1.74
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2
APPENDIX A
MATERIALS DESIGN REPORT
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
ROSEMONT COPPER T-INTERSECTIONPIMA COUNTY, ARIZONA
PAVEMENT STRUCTURAL SECTION No. 6SOUTH DETOUR
5” AGGREGATE BASECLASS - 2
MIN 10” OF SCARIFIED,MOISTURE CONDITIONED, AND
RECOMPACTED SUBGRADE
2.5” AC - END PRODUCTSHRP VOLUMETRIC MIX
6
DATE:
5/12
PAVEMENT STRUCTURAL SECTION No. 6SOUTH DETOUR
5” AGGREGATE BASECLASS - 2
MIN 10” OF SCARIFIED,MOISTURE CONDITIONED, AND
RECOMPACTED SUBGRADE
2.5” AC - END PRODUCTSHRP VOLUMETRIC MIX
PAVEMENT STRUCTURAL SECTION No. 1
4” AGGREGATE BASECLASS - 2
2.5” AC (3/4)FOGCOAT
SUBGRADE
PAVEMENT STRUCTURAL SECTION No. 2
4” PCCP
SUBGRADE
4” AGGREGATE BASECLASS - 2
PAVEMENT STRUCTURALSECTION No. 1 OR 2
TYPICAL SECTIONSTA 165+22 TO 173+50STA 176+50 TO 191+30
TYPICAL SECTIONSTA 19+00 TO 19+14
5” AGGREGATE BASECLASS 2
3” AC (MISC STR)
TACK COAT
SUBGRADE
3” AC (MISC STR)
PAVEMENT STRUCTURAL SECTION
Shoulder Buildup
TYPICAL SECTIONSTA 165+22 TO 173+50STA 176+50 TO 191+30
TYPICAL SECTIONSTA 173+50 TO 174+20STA 174+20 TO 175+80STA 175+80 TO 176+50
Shoulder Buildup
TYPICAL SECTIONSTA 19+23 TO 19+70
9” AGGREGATE BASECLASS 6
SUBGRADE
SHOULDER BUILDUP
TEMPORARY PAVEMENT
E
E
TEMPORARY PAVEMENT
2.5 Inches AC(Misc Str) (Special Mix)
5.0 Inches AB(Class 2)
Subgrade
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2
SECTION II – SUBGRADE, SUBBASES, AND BASES
ITEM 1 – SUBGRADE CONSTRUCTION CONTROL
The attached Subgrade Acceptance Chart shall be used during construction for determining whether subgrade materials are suitable as outlined in Section 203.03 (D) of the ADOT Construction Manual.
ITEM 2 – AGGREGATE BASE (CLASS 2)
The Aggregate Base shall consist of one or more of the following:
1. The Aggregate Base shall be Class 2 and shall be as specified in Section 303 of the Standard Specifications.
2. The Aggregate Base shall be Class 2 and shall be as specified in Section 303 of the Standard Specifications, and Contracts and Specifications Stored Specifications “303SALV.”
The estimated haul distance for the Aggregate Base is 20 miles.
ITEM 3 – AGGREGATE SUBBASE (CLASS 6)
The Aggregate Subbase shall consist of one or more of the following:
1. The Aggregate Subbase shall be Class 6 and shall be as specified in Section 303 of the Standard Specifications.
2. The Aggregate Subbase shall be Class 6 and shall be as specified in Section 303 of the Standard Specifications, and Contracts and Specifications Stored Spec. “303SALV.”
The grading shall be as follows:
Sieve Size % Passing
3” 100 ¼” 45 - 75
#200 0 – 15.0
The plasticity index shall not exceed 5.
The estimated haul distance for the Aggregate Subbase is 20 miles.
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2
SECTION III – SURFACE TREATMENTS AND PAVEMENTS
ITEM 1 – TACK COAT
A tack coat shall be applied as necessary to provide proper bonding prior to the placement of each lift of AC (Miscellaneous Structural – Special Mix) over an underlying bituminous surface, or PCCP surface.
The tack coat shall be as specified in Section 404 of the Standard Specifications and Contracts and Specifications Stored Specifications "404BITUM."
ITEM 2 - PORTLAND CEMENT CONCRETE PAVEMENT
The work under this Item shall consist of furnishing all materials and constructing a Plain Jointed Portland Cement Concrete Pavement as specified in Section 401 of the Standard Specifications, and Contracts and Specifications Stored Specifications "401PCCP" and “1011JMAT”.
The asphaltic concrete shall be as specified in Section 409 of the Standard Specifications, and Contracts and Specification Stored Spec. "409AGGR", with the following exception:
409-2.01 Mineral Aggregate: “Carbonates” and “Note 1” are added to the table:
Mineral Aggregate Characteristics Test Method Requirement
Carbonates (1) Arizona Test Method 238 Maximum 20%
(1): Testing for carbonates only applies if either of the following conditions exist: (a) The asphaltic concrete is the designed final pavement surface normally used by traffic. (b) The asphaltic concrete, temporary or otherwise, will be subject to traffic for more than 60 days.
For estimating purposes, the unit weight of the bituminous mix is 145 pounds per cubic foot.
The asphalt cement type shall be PG 64-22.
The estimated haul distance for the asphaltic concrete is 20 miles.
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2
ITEM 4 – POLYMER CHIP SEAL COAT
The Chip Seal Coat shall be as specified in Section 404 of the Standard Specifications, and
Contracts and Specifications Stored Spec. “404BITUM”, with the following exception.
404-3.14 Chip Seal Coat: the second and third paragraphs of the Standard
Specifications are revised to read:
The type of bituminous material shall be CRS-2P and shall be applied at the approximate
rate of 0.50 gallons per square yard.
Cover material shall be applied at the rate of approximately 0.012 cubic yards per square
yard; however, the Engineer will specify the exact rate to be applied based on the
characteristics of the aggregate material and the surface to be treated.
The gradation of cover material shall meet the requirements for Class 1.
The estimated haul distance for the cover material is 20 miles.
The average elevation of the roadway for this project is 4,486 feet.
ITEM 5 – FOG COAT
The fog coat shall be as specified in Section 404 of the Standard Specifications and Contracts and Specifications Stored Spec. "404BITUM."
The bituminous material shall be SS-1.
The bituminous material shall be applied at a rate of 0.08 gallons per square yard.
The blotter material shall be applied at a total rate of approximately 2 pounds per square yard.
The estimated haul distance for the blotter material is 20 miles.
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2
SECTION IV – MATERIALS SOURCES – GEOTECHNICAL ANALYSIS
There is no Department furnished source for borrow on this project. Borrow shall be as specified in Section 203-9 of the Standard Specifications. Borrow placed within three (3) feet of finished subgrade elevation shall meet the following requirements:
The Plasticity Index (PI) (AASHTO T90) and the percent passing the No. 200 Sieve (Minus 200) (Ariz. Test Method 201) when used in the equation below, shall give a value of X that does not exceed 87.
X = (Minus 200) + [2.83 (PI)]
ITEM 2 – MATERIAL SOURCES
Materials sources shall be as specified in Contracts and Specifications Section Stored Specifications “1001MATL” and “104ENVIR”.
ITEM 3 – EARTHWORK FACTORS AND SLOPES
We recommend an earthwork factor of 10 percent shrink. Permanent cut or fill slopes associated with this project should be constructed no steeper than 2:1 (H:V).
ITEM 4 – GROUND COMPACTION
The following ground compaction factors shall be compensated for on embankment sections outside the existing roadway prism.
Station Ground Compaction (ft)
165+22.00 to 191+30.00 0.2
ITEM 5 – EARTHWORK FACTORS AND SLOPES
The following excavation factors and slopes shall be used for the project development.
Station Excavation Factor Slope
165+22.00 to 191+30.00 10% (shrink) 2(H):1(V)
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2
ITEM 6 – PH AND RESISTIVITY
If corrugated metal pipe culverts are to be used, then the type of metal pipe and coating should be determined by the pH and resistivity of in-place materials listed below:
Corrosivity Test Results
Test Location Approximate Station, Offset
Water Soluble Sulfate Content
in Soil, %
Chloride Content,
ppm pH Resistivity
(ohm-cm)
HS-1 187+00; 80RT 0.002 10 7.0 3,488
ITEM 7 – WATER
Approximately 90 gallons of water per cubic yard may be estimated for compaction of embankment materials, and approximately 70 gallons of water per cubic yard for compaction of AB materials.
The application of water estimated for subgrade materials is considerably higher than the amount calculated based upon the difference between in-situ and optimum compaction moisture content, and includes a conservative overrun for losses due to seepage, evaporation, inadequate mixing, spillage, etc. Precipitation during and/or before construction may reduce the required amount of water.
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2
SECTION V – MISCELLANEOUS
ITEM 1 – BITUMINOUS PAVEMENT REMOVAL
The work under this Item consists of removal and disposal of the asphaltic concrete pavement material as specified in Section 202 of the Standard Specifications.
ITEM 3 – DISPOSAL OF EXISTING ASPHALTIC CONCRETE
Upon removal, disposal of the existing asphaltic concrete shall be the responsibility of the contractor.
ITEM 4 – TEMPORARY CONNECTIONS AND DETOURS
The temporary surfacing shall consist of 2.5 inches of AC (Miscellaneous Structural – Special Mix) placed over 5 inches of Aggregate Base (Class 2).
At a time specified by the Engineer, the bituminous surfacing and the base material shall be broken up, picked up separately, and stockpiled individually at sites designated by the Engineer. The remaining detour roadways shall be removed, and the natural subgrade shall be restored as nearly as practicable to the condition existing prior to the construction of the detour.
No measurements for payment will be made for the work of removing the detours and stockpiling the material, the cost being considered as included in the cost of the contract items.
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2
PRELIMINARY PAVEMENT STRUCTURE COST ESTIMATE
ITEM NO. ITEM DESCRIPTION UNIT QNTY UNIT PRICE ($) AMOUNT($)
3030022 Aggregate Base, Class 2 CY 2,755 50 137,750
3030026 Aggregate Subbase, Class 6 CY 318 70 22,260
4010009 Portland Cement Concrete Pavement (9”) SY 4,912 65 319,280
4040073 Emulsified Asphalt (CRS-2P) Ton 13 1,000 13,000
4040125 Fog Coat Ton 1 1,500 1,500
4040162 Cover Material CY 77 80 6,160
4040163 Blotter Material Ton 3 50 150
4090006 AC (Miscellaneous Structural) (Special Mix) Ton 4,310 90 387,900
TOTAL 888,000
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
603596001R Pavement rev 2
APPENDIX B
DARWIN PAVEMENT ANALYSIS PRINTOUTS
Pavement Design Summary May 25, 2012 Rosemont Copper T-Intersection Project No. 603596001 Pima County, Arizona
Nt=number of measured R-valuesNc=number of correlated R-valuesRt=adjusted average of the measured valuesRc=adjusted average of the correlated valuesSDt=std deviation of the measured valuesSDc=std deviation of the correlated values