UT FLAP 2500(1) Taylor Mountain Road Pavement Report -final 07-06-21 .pdf

UT FLAP 2500(1) Taylor Mountain Road

PAVEMENT AND MATERIALS REPORT

November 2020

Report Prepared By

U.S. Department of Transportation Federal Highway Administration

Central Federal Lands Highway Division Lakewood, Colorado ii

Written by: ________________________________________________________ Marty Fey, Pavements & Materials Engineer

Approved for distribution by:

Mike Voth, Pavements and Materials Discipline Champion

Distribution:

Project Development Project Management Construction Materials Pavements Geotech iii

TABLE OF CONTENTS

I. INTRODUCTION

II. CLIMATE

III. EXPLORATION

IV. EXISTING PAVEMENT & SOILS

V. PAVEMENT DESIGN CALCULATION INPUTS

VI. PAVEMENT RECOMMENDATIONS & DISCUSSION

VII. MATERIALS RECOMMENDATIONS

APPENDICES

A – Location Map B – Laboratory Reports and Boring Log C – Photographs D – AASHTO ’93 Flexible Pavement Design E – PG LTPPBIND Software F – Preliminary Pavement Recommendation Memo

I. INTRODUCTION

This report is written to provide pavement and materials recommendations for UT FLAP 2500(1) Taylor Mountain Road. The project is located north of Vernal, Utah in Uintah County. Taylor Mountain Road, also known as N 2500 W, runs from the intersection of W 3500 N on the south end of the project to the Ashley National Forest boundary on the north. The project may also include improvements to the gravel parking area on the north end of the project. See Appendix A for location map.

The Preliminary Pavement Recommendations Memo was issued in November, 2019. The memo provided the pavement recommendations as well as the proposed pay items. This memo is found in Appendix F. The pavement recommendations have been finalized and are discussed in Part VI of this report.

II. CLIMATE

Climate data was obtained from noaa.gov. This data is summarized in Table 1 below.

The average annual precipitation for this area is approximately 9.31 inches. The project is located in a mountainous area and at an elevation that receives both snow and rain, dependent upon the time of year.

Table 1: Weather Data

Month Average

LOW (°F)

Average

HIGH (°F)

Average

MEAN (°F)

Average

PRECIP. (in)

January 9.7 28.4 19.0 0.50

February 15.9 35.8 25.8 0.52

March 26.4 49.4 37.9 0.68

April 34.1 59.4 46.7 0.82

May 43.2 70.0 56.6 0.89

June 50.5 80.2 65.3 0.80

July 56.8 87.5 72.1 0.64

August 55.3 85.1 70.2 0.76

September 45.7 74.7 60.2 1.08

October 35.4 60.9 48.1 1.39

November 23.7 44.5 34.1 0.59

December 12.9 30.6 21.8 0.64

III. EXPLORATION

On August 8th, 2019, a pavement and subgrade soil investigation was conducted by CFL’s Marty Fey and Ashley Anaya which included boring and subgrade sampling. Prior to the investigation, CFL made a separate trip to mark proposed boring locations and called 811 for utility locates. Haz-Tech Drilling was hired through the CFLHD BPA to assist with the field investigation. A BK-81 truck-mounted drill rig with an 8” O.D. auger was used to complete the borings. Pavement borings were logged at 14 locations, and subgrade samples were collected to be tested in the laboratory. CFL personnel logged the borings; this included depth of boring, visual soil classification, and pavement thickness when applicable. Boring locations, test results, and other information is shown in Appendix B.

Two additional geotech borings were drilled and sampled. Results and analysis of these borings are available in a separate geotech report.

IV. EXISTING PAVEMENT & SOILS

The existing roadway was observed to consist of old, oxidized asphalt pavement with high severity fatigue cracking extending throughout the length of the project. The majority of the project, sta 33+50.00 to 295+00.00, is a good candidate for full depth reclamation. The final portion of the roadway, sta 295+00.00 to 385+47.72, is steeper and rockier which could make FDR operations difficult. A full reconstruction is recommended in this area.

Pavement thickness was found to be 1.5 to 12 inches in depth at the locations drilled, supported by 0 to 12 inches of aggregate road base.

The subgrade materials encountered are of good quality. The subgrade soils encountered consisted primarily of silty and clayey sands with some gravel and were classified as A- 2-4(0) and A-4. Subgrade soils exhibited low plasticity and had R-values of 45-67. See the laboratory reports and boring logs in Appendix B for more information.

Drilling efforts were relatively easy, with refusal in 6 borings encountered at depths ranging from 1 to 4 feet.

Some cobbles and boulders were encountered during the drilling exploration at depths below the structural section. Because this project is located in a mountainous area, boulders and cobbles may be encountered.

V. PAVEMENT DESIGN CALCULATION INPUTS

Design Parameters

Traffic counts were provided with the FLAP application and were used to develop ESAL estimates. An average daily traffic (ADT) of 600 and a truck factor of 5% class 5 and 1% class 8 was used, resulting in a calculated cumulative equivalent single axel load (ESALs) of 133,000 for a 20-year period. The assumptions made in the ESAL calculations as well as related design factors are included in Appendix D. Design factors used in the ESALs calculations as well as the structural coefficients were taken from the CFLHD Project Development Design Manual (PDDM), Chapter 11.

Roadbed Soil Resilient Modulus

The soil resilient modulus was converted from R-Values, AASHTO T 190, using the following equation:

Resilient Modulus (psi) = 10[ ( S

+ 18.72 ) / 6.24 ] where S1 = [(R-Value – 5) / 11.29] + 3

An average R-value of 45 was used to generate a design resilient modulus of 11,000 psi.

VI. PAVEMENT RECOMMENDATIONS & DISCUSSION

Utilizing AASHTO 93 Flexible Pavement Design (Appendix D), a 20-year pavement design required a Calculated Design Structural Number (SN) of 1.95. After evaluating various alternatives and performing various iterations, the following is the recommended pavement structural section:

Table 2: Recommended Pavement Section Layer Thickness

HACP 3 inches (two lifts) Full Depth Reclamation (FDR) or Aggregate Base in widened/reconstructed areas

6 inches

SN = 2.04

Portions of the roadway with asphalt patches thicker than 6” were observed in several areas throughout the project.

VII. MATERIALS RECOMMENDATIONS

Selection of Asphalt Binder

LTPPBind software was utilized to assist in the selection of asphalt binder. The information presented in LTPPBind is shown in Appendix E. LTPPBind indicated that a PG 64-28 binder should be used. Consideration was given to the location of the project as well as performance of past projects in similar condition.

Prime and Tack Coats, Blotter and Fog Seal

Prime Coat and Blotter are recommended for this project. A tack coat applied between pavement lifts is recommended. It is also recommended that a fog seal be applied to the final surfacing.

Drainage and Subexcavation

During the field investigation, areas of pavement distress were present. However, they appeared to be caused due to fatigue and age. No major water damage or drainage problems pertaining to the existing traveled way were observed. If any drainage issues are encountered, the scope of the project allows for partial reconstruction. A quantity of 100 cubic yards of subexcavation should be included in the contract. This quantity should remain in the Contract in the event that areas in need of repair are encountered.

Bid Items

Suggested FP-14 pay items for the proposed structural section are shown in Table 3 below.

Table 3: Recommended Pay Items

Item Number Item Description Unit

20402-0000 Subexcavation CUYD

30202-2000 Roadway Aggregate, Method 2 TON

30401-5300 Full Depth Reclamation, Method 2, 6-inch SQYD

40101-5600 Asphalt Concrete Pavement, Gyratory Mix, ½” or ¾” NMA, 0.3 to < 3 M ESALs

TON

40105-3000 Antistrip Additive Type 3 TON

40601-0000 Fog Seal TON

41101-1000 Prime Coat, Method 1 TON

41105-0000 Blotter TON

41201-0000 Tack Coat TON

APPENDICES

A – Location Map

B – Laboratory Reports and Boring Log

C – Photographs

D – AASHTO ’93 Flexible Pavement Design

E – PG LTPPBind Software

F – Preliminary Pavement Recommendation Memo

Appendix A: Location Map

Appendix B: Laboratory Reports and Boring Logs

Project:

Sample Number

Station or Location

Offset from CL

Date Sampled

Depth of Bore

Container Type

Pavement/ABC Thickness R-Value Class Moisture % Resistivity, ohm.cm pH Sulfate % Chloride %

0 to 4"

4" to 7.5" SM / A-2-4(0) 7.5" to 5'

0 to 3.5"

3.5" to 9.5"

9.5" to 5'

0 to 3.5"

3.5" to 8"

8" to 4'

4' to 5'

0 to 4"

4" to 8" SM / A-2-4(0) 8" to 5'

0 to 4"

4" to 8"

8" to 2'

0 to 4"

4" to 16" CL / A-4(3) 16" to 5'

0 to 9"

9" to 5'

0 to 4"

4" to 7.5" CL-ML / A-4(1) 7.5" to 11.5'

0 to 12"

12" to 5' ML / A-4(10)

0 to 4"

4" to 8.5" SM / A-4(0) 8.5" to 5'

0 to 1.5"

1.5" to 5.5"

5.5" to 13"

13" to 5'

0 to 1.5"

1.5" to 6"

6" to 9"

9" to 4'

0 to 1.5"

1.5" to 5.5"

5.5" to 8.5"

9" to 4'

0 to 4"

4" to 1' 66 GC-GM / A-1-a(0)

SM / A-2-4(0)

45 ML / A-4(0)

Sand Clayey, Brown Sand Silty, White

862 8.7 Aggregate Base Course, Brown Sand Silty, Brown

P-8

3.0 Mi N of

int W 3500

N 4' Rt 8/8/2019 11.5'

5-gal bucket

Asphalt Classification

Near culvert in distressed area. 4"/3.5"Aggregate Base Course, Brown

Clay Sandy, Brown

3.5"/4.5"

BK-81 truck mounted (8"O.D. HSA)

Haz-Tech Drilling Pavement Investigation - Shallow Borings and Cores - Log & Sampling Summary

8.6

8.4

8.6

1,591

4"/12"

9"/0"

12"/0"

4"/4.5"

1.5"/4"

1.5"/4.5"

0"/4"

1.5"/4"

P-14

Parking Area, 6.5

Mi N of int W 3500 N

25' Lt Refusal at 1', Exposed Limestone at Surface

Gravel clayey, dark brown, moist

P-13

5.5 Mi N of

int W 3500

N 4' Lt 8/8/2019 4'

5-gal bucket

Asphalt

Classification Refusal @ 4' on Limestone

5-gal bucket

Asphalt Classification, R-Value, Resistivity and pH

5-gal bucket

Classification

P-11

4.5 Mi N of

int W 3500

N

P-9

3.6 Mi N of

int W 3500

N 4' Lt 8/8/2019 5'

5-gal bucket

Asphalt

P-7

2.7 Mi N of

int W 3500

N 4' Lt 8/8/2019 5'

5-gal bucket

Asphalt Classification, R-Value, Resistivity and pH Silt Sandy, Brown

P-2

0.5 Mi N of

int W 3500

N 4' Rt 8/8/2019 5'

5-gal bucket

Asphalt ClassificationAggregate Base Course, Brown

Sand Silty, Brown

P-4

1.5 Mi N of

int W 3500

N 4' Rt 8/8/2019

Asphalt Aggregate Base Course, Brown Sand Silty w/ Cobbles, Brown

None2'

P-6

P-5

Comments

Refusal at 2'

Testing Requested

UT FLAP 2500(1) Taylor Mountain Road Contractor:

Logged By: Equipment:Sampled By:Marty Fey Marty Fey / Ashley Anaya

8/8/20194' Lt

0.1 Mi N of

int W 3500

N

Boring Observations (grey = sample depth )

Asphalt Aggregate Base Course, Brown Sand Silty, Brown

Asphalt

P-3

1.0 Mi N of

int W 3500

N 4' Lt 8/8/2019

2.5 Mi N of

int W 3500

N

5-gal bucket

Asphalt

4"/3.5"

3.5"/6"

Classification

ClassificationAggregate Base Course, Brown Sand Silty, Dark Brown

5-gal bucket

8/8/20194' Lt

2.0 Mi N of

int W 3500

N

Sand, White

Asphalt

5' 4"/4"

4"/4"

5' 5-gal bucket Classification, R-Value, Resistivity and pH

4' Rt 5-gal bucket

8/8/2019 1' 5-gal bucket

Aggregate Base Course, Brown Classification, R-Value, Resistivity and pH

8/8/2019

P-10

3.9 Mi N of

int W 3500

N 8/8/20194' Rt 5'

P-12

5.0 Mi N of

int W 3500

N

4' Lt 8/8/2019 5'

4'

4' Rt

Asphalt

Sand Silty, White

Aggregate Base Course, Brown Clay Sandy, Brown

Asphalt Aggregate Base Course, Brown

Aggregate Base Course, Brown Clay Sandy, Brown

P-1 5' 5-gal bucket

8/8/2019 5' 5-gal bucket Classification

67 SM / A-2-4(0)

Sand Clayey, Brown

SC-SM / A-4(1)

Sand Clayey, Brown SC-SM / A-1-b(0)

Aggregate Base Course, Brown

SM / A-2-4(0)

Classification

ClassificationClay Sandy, Brown

Aggregate Base Course, Brown

Sand Silty, White

Refusal at 4'

Appendix C: Photographs

Photo 1: Haz‐tech Drilling performing drilling operations.

Photo 2: Existing asphalt pavement

Photo 3: Utility Locates

Photo 4: Bulk Sample Collection

Photo 5: Cobbles in boring P‐5

Photo 6: Possible sub‐ex area, boring P‐11

Photo 7: SPT sampler

Photo 8: Steep and rocky, sta 265+00 to sta 385+91.07

Photo 9: Gravel Parking Area

Photo 10: Typical Mountain Terrain

Appendix D: AASHTO ’93 Flexible Pavement Design

AASHTO FLEXIBLE PAVEMENT DESIGN

Layer Thickness Determination Using Trial and Error

Layer Drainage Layer Layer No. Description Coefficient, ai Coefficient, mi Thickness, in SN

(topmost) Layer 1 AC Layer 0.44 1.00 3.00 1.32 Layer 2 FDR 0.12 1.00 6.00 0.72 Layer 3 Gran. Subbase 0.12 1.00 0.00 0.00 Layer 4 Select Borrow 0.08 0.90 0.00 0.00 Layer 5 0.00 Layer 6 0.00 Layer 7 0.00

(bottommost) Layer 8 0.00 Subgrade Subgrade N/A N/A N/A N/A

AC Layer 401 = 0.44 Trial SN 2.04 403 = 0.40

CAB 301 = 0.14 Design SN to Match 1.95 Subbase/Minor agg 302 = 0.12 FDR 304 = 0.12 Design is sufficient Select borrow 204 = 0.06 to 0.08 (Refer to Exhibit 11.2-C in Chapter 11 of PDDM for additional guidance on coefficients)

AASHTO FLEXIBLE PAVEMENT DESIGN

SN Determination

Design Inputs W18 = 133,000 ESALs Applications Over Design Period Typ. Range 50k to 10 million

R = 75 % Reliability Typ. Range 75 to 95%

So = 0.49 Standard Deviation AASHTO Standard

MR = 11,000 psi Subgrade Resilient Modulus Typ. Range 3000 to 15000 psi

Pi = 4.2 Initial Serviceability Typ. Range 4.2 to 4.4

Pt = 2.5 Terminal Serviceability Typ. Range 2.0 to 3.0

DESIGN SN = 1.95

R-Value = 65 S1 = 8.314 MR = 21500 R-Value = 45 S1 = 6.543 MR = 11183

R-Value Correlation to Resilient Modulus*

Only change the R-values in C4 or C5. The rest is automatically calculated.

*CDOT method. Similar to results from Figure FF.6 in Volume 2 of AGDPS and used by CFLHD.

ADT 600 Annual Growth 0.02 Design Years 20

Directional Distribution

0.6

Lane Distribution

Classification Percent Truck Factor

Growth Factor ADT Yr 1 Design Lane ESALs ADT at N

Autos 54.0% 0.0006 324 0 481 Values Pickups, Vans 40.0% 0.004 24.29737 240 5108 357

892 (calculated) Class 4 buses 0.0% 1.5 24.29737 0 0 0 600 Class 5 trucks/RVs 5.0% 0.5 24.29737 30 79817 45

2019 Class 6 0.0% 1 24.29737 0 0 0 2039 Class 8 1.0% 1.5 24.29737 6 47890 9

2 Class 9 0.0% 2 24.29737 0 0 0 100.00% 132815 892

(refer to Exhibit 11.2-A in the PDDM for additional guidance on truck factors)

GR = Growth Rate (%)

Future ADT Calculation ADTf = ADTi (1 + GR)(F-I)

ADTf = Average daily traffic for future year ADTi = Average daily traffic for initial year

I = Initial year for ADT F = Future year for ADT

Appendix E: PG LTPPBind Software

BindReport‐5Closest.txt

Five Closest Weather Stations For Latitude/Longitude= 40.456/109.489 Report Date: 11/18/2019 (LTPPBind V3.0 Alpha)

UT FLAP 2500(1) Taylor Mountain Road ‐ LTTPBind

General A=3 km B=15 km C=16 km D=20 km E=37 km Station ID UT9111 UT4342 UT2173 UT5268 UT2996 County/District uintah uintah uintah uintah uintah Weather Station vernal municipa jensen dinosaur quarry maeser 9 nw fort duchesne Elevation, m 1490 1345 1351 1824 1430 Latitude, Longitude 40.45 ,109.52 40.37 ,109.35 40.43 ,109.3 40.57 ,109.67 40.28 ,109.87 Last Year Data Available 1997 1997 1997 1997 1997

Air Temperature Mean ( Std, N ) Mean ( Std, N ) Mean ( Std, N ) Mean ( Std, N ) Mean ( Std, N ) High Temperature 34.7 (12,35) 35.4 (11,35) 37.5 (13,34) 31.5 (16,14) 35.5 (11,33) Low Temperature ‐26.3 (45,35) ‐29.5 (48,35) ‐28.1 (50,34) ‐25 (50,14) ‐28 (53,34) Low Temperature Drop 25.6 (25,35) 28 (18,35) 27.4 (23,34) 23.8 (32,14) 28.5 (24,34) Degree‐Days > 10C 2995 (205,35) 3142 (212,35) 3419 (228,34) 2469 (176,14) 3053 (207,33)

PG High Low Rel. High Low Rel. High Low Rel. High Low Rel. High Low Rel.

Pavement Temperature, C 56.5 ‐18.3 57.7 ‐20.6 59.8 ‐19.6 51.9 ‐17.4 57.0 ‐19.5 50% Reliability PG 58‐22 (88,83) 58‐22 (60,64) 64‐22 (98,72) 52‐22 (54,86) 58‐22 (80,72) >50% Reliability PG 58‐28 (88,98) 64‐22 (98,64) 64‐28 (98,97) 58‐22 (98,86) 58‐28 (80,97) = 64‐28 (98,98) 64‐28 (98,96) 64‐34 (98,98) 58‐28 (98,98) 64‐28 (98,97) = 64‐34 (98,98) 64‐34 (98,98)

Appendix F: Preliminary Pavement Recommendations Memo

Subject: Preliminary Pavement & Materials Recommendations (V1) NV FLAP 2500(1) Taylor Mountain Road

From: Marty Fey Pavement & Materials Engineer, CFLHD

To: Braden Peters, Project Manager, CFLHD Kelly Terrell, Design Engineer, CFLHD

INTRODUCTION

This memorandum provides preliminary pavement and material recommendations for the Taylor Mountain Road project located in Uintah County, north of Vernal, Utah.

Taylor Mountain Road, also known as N 2500 W, runs from the intersection of W 3500 N on the south end of the project to the National Forest boundary on the north. The project may also include improvements to the gravel parking area on the north end of the project.

CFLHD standards and guidelines were used to complete the pavement and materials recommendations.

FIELD INVESTIGATION

On August 8th, 2019 CFLHD pavement & material staff completed a field investigation which included boring and subgrade sampling. Haz-Tech Drilling was hired through the CFLHD BPA to assist with the field investigation. A BK-81 truck-mounted drill rig with an 8” O.D. auger was used to complete the borings. Pavement boring were logged at 14 locations, subgrade samples were collected and tested in the laboratory. See the attached boring and testing logs for more detailed information.

Two additional geotech borings were drilled and sampled. Results and analysis of these borings is available in a separate geotech report.

The primary objectives of this field investigation were as follows:

• Measure and record existing pavement and subgrade layer depths;

• Gather subgrade soil samples for follow-up testing to determine engineering properties;

• Evaluate and record pavement distress conditions;

Technical Memorandum

Date: November 12, 2019

• Evaluate roadway and project area for constructability concerns.

The existing roadway was observed to consist of old, oxidized asphalt pavement with high severity fatigue cracking extending throughout the length of the project. This roadway would be a good candidate for full depth reclamation.

The information gathered as described above was used to support pavement rehabilitation, structural design, and material recommendations.

Below are summary tables of data gathered and test results. For more complete and detailed results, see the attached logs and lab test reports.

Summary of Sampling & Test Results

Pavement Depth

Roadbase

Depth R-value, subbase

R-value, subgrade Comments

1.5 to 12 inches

0 to 12 inches

N/A 45 - 67

• Subgrade material consists primarily of Silty and Clayey Sands with some gravel, A-2-4(0) and A-4.

• Resistivity values are low and indicate minimal risk of sulfate and chloride attack.

TRAFFIC:

Traffic counts were provided with the FLAP application and used to developed estimates for ESALs. The road is primarily used for recreational and residential access with little commercial use. Truck counts were based on engineering judgement and are assumed to be very low. The counts appear generally consistent with other historical traffic data and they align with what was experienced during the field investigation. The following is a summary of traffic data as well as the estimated ESALs used for design:

• 2019 ADT = 600

• 2039 ADT = 892 (2% growth rate)

• 2019 % trucks = 5% Class 5 (trucks/RVs), 1% Class 8

• Directional factor = 60%

• Design Lane ESAL’s = 133,000

The 20-year 18-kip equivalent single axle load (ESAL) used for design was 133,000.

DESIGN RECOMMENDATIONS

The pavement design, rehabilitation method, and other recommendations are included below.

In developing the pavement structural and rehabilitation recommendations the following criteria was used:

Design Criteria Initial Serviceability 4.2 Terminal Serviceability 2.5 Design Reliability Level 75% Overall Standard Deviation 0.49 Soil Resilient Modulus (average R-value = 45) 11,000 psi Performance Period (4R) 20 years 20-year ESAL 133,000 Existing Borrow Material R-Value 45 Calculated Structural Number (SN) 1.95

The following is the recommended pavement structural section.

Pulverize and Overlay Layer Thickness

HACP 3 inches (two lifts) Full Depth Reclamation (FDR) or Aggregate Base Course in widened/reconstructed areas

6 inches

SN = 2.04

Portions of the roadway with asphalt patches thicker than 6” were observed in isolated areas. The excess HMA will need to be removed and these areas will need to be subexed to the depth of the existing HMA or to 6” below top of final grade, whichever is greater. An extra quantity of 500 CY of subexcavation should be assumed for this operation.

ADDITIONAL RECOMMENDATIONS:

• The asphalt binder grade should be PG 64-28. This aligns with recommendations from LTPPBind.

• Include a nominal amount of subexcavation (~1000 cu yd total) to be used at discretion of the CO.

• Recommend the following bid items.

Item Number Item Description Unit 20402-0000 Subexcavation CUYD 30202-2000 Roadway Aggregate, Method 2 TON 30401-5300 Full Depth Reclamation, Method 2, 6-inch SQYD

40101-0500 Asphalt Concrete Pavement, Gyratory Mix, ½” Nominal Max Size Aggregate, <0.3 Million ESAL

TON

40601-0000 Fog Seal TON 40605-0000 Blotter TON 41101-0000 Prime Coat TON 41201-0000 Tack Coat TON

CONSTRUCTION CONSIDERATIONS & SPECIAL CONTRACT PROVISIONS

CFLHD standard SCR’s related to pavements & materials will be used. Depending upon the decision of whether or not to use a local borrow source and/or develop a source, an SCR may need to be developed.

Attachments:

Lab Test Reports Boring Logs & Charts LTPPBind Report Pavement Design