CA FLAP MOD 258(1) Blue Lake Road Pavement Report -Final.pdf

CA FLAP MOD 258(1) Blue Lake Road Modoc National Forest

PAVEMENT AND MATERIALS REPORT

January 2021

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

Reviewed and 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 G – Alternative Cost Analysis

I. INTRODUCTION

This report is written to provide pavement and materials recommendations for CA FLAP MOD 258(1) Blue Lake Road. Blue Lake Road, also known as CR 258 or Old Blue Lake Road, runs from the intersection of CR 64 on the north end of the project 6.5 miles south to the Blue Lake Campground turnoff. Also included in this investigation are the Campground and Boat Ramp Access Roads, Campground Loop Roads, and the Blue Lake Pedestrian Trail. Two potential rock fall mitigation areas on CR 64 were also explored as part of this investigation. See Appendix A for location map.

The Preliminary Pavement Recommendations Memo was issued in March, 2020. 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 11.99 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

HIGH (°F)

Average

LOW (°F)

Average

MEAN (°F)

Average

PRECIP. (in)

January 41.0 23.1 32.0 1.97

February 46.3 26.3 36.3 1.78

March 54.3 31.1 42.7 1.53

April 60.9 34.9 47.9 0.63

May 70.3 41.3 55.8 0.71

June 79.4 47.5 63.4 0.44

July 88.7 53.2 71.0 0.22

August 87.5 51.7 69.6 0.12

September 79.0 44.8 61.9 0.37

October 65.8 36.7 51.2 1.00

November 50.6 28.9 39.8 1.75

December 41.0 23.1 32.0 1.47

III. EXPLORATION

On November 4th and 5th, 2019 CFLHD pavement & materials engineer Marty Fey completed a field investigation which included boring and subgrade sampling. Diamond Core Drilling was hired through the CFLHD BPA to assist with the field investigation. A Mobile B80 truck-mounted drill rig with an 8” O.D. hollow stem auger was used to complete the borings. Pavement borings were logged at 20 locations along Blue Lake Road and at two locations on CR 64. An additional visit was made by Marty Fey on September 23rd, 2020 to collect pavement and subgrade data for the Access Road, Campground Loop, and Pedestrian Trail. Subgrade samples were collected and tested in the laboratory. Boring locations, test results, and other information can be found in Appendix B.

IV. EXISTING PAVEMENT & SOILS

The existing pavement of CR 258, the campground access road, and campground loop were observed to consist of old, oxidized asphalt pavement with high severity fatigue cracking and potholing extending throughout the length of the project. These roadways would be good candidates for full depth reclamation.

CR 64 was paved by FHWA in 1995 and is performing well. Preventative maintenance has been performed including a recent chip seal.

Subgrade materials supporting CR 258, the access road, and the campground loop consist primarily of A-6 and A-7 Clayey Sands. Some high plasticity clays were also observed under the roadway. During testing, low subgrade R-values were found. Low R-values indicate the material has very poor support characteristics and will require a stronger pavement section. The subgrade supporting CR 64 was found to have a higher R-value and relatively good support characteristics. Laboratory testing indicates a low risk of sulfate and chloride attack.

Table 2, below, summarizes the data gathered and laboratory test results. For more complete and detailed results, see the attached boring logs and lab test reports in Appendix B.

Table 2: Summary of Sampling and Test Results

Segment Pavement

Depth Roadbase

Depth Subgrade R-Value

Plasticity Index

CR 258

2 to 3 ¼ “ 0 to 5 “ < 5 to 17 12 to 38

Campground Access Road

2 to 3 ½ “ 4 “ 36 13

Campground Loop

¾ to 1 “ 0 to 2 “ - -

CR 64

4 to 5 ¼ “ 6 “ 66 to 78 3 to 7

Drilling efforts were relatively easy, with refusal in 4 borings encountered at depths ranging from 3 to

4.5 feet. The Blue Lake Road project is in a mountainous are, cobbles and boulders may be encountered.

Some cobbles and boulders were encountered during the drilling exploration at depths below the structural section.

V. PAVEMENT DESIGN CALCULATION INPUTS

Design Parameters

Traffic counts for CR 258 were provided with the FLAP application and were used to develop ESAL estimates. An average daily traffic (ADT) of 100 with truck percentages of 10% class 5 and 1% class 8 was used, resulting in a calculated cumulative equivalent single axel load (ESALs) of 35,268 for a 20-year period. The AASHTO minimum of 50,000 ESALs was used for calculations. 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 10 was used to generate a design resilient modulus of 3,500 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 2.52. After evaluating various alternatives and performing various iterations, the following is the recommended pavement structural section:

Table 3: Recommended Pavement Section, CR 258, Campground Access Road, Campground Loop

Layer Thickness HACP 3 inches (two lifts) Full Depth Reclamation (FDR) w/ Cement or Aggregate Base in reconstructed areas

6 inches

SN = 2.52

No aggregate base course was observed under the pavement of CR 258 from MM 1.0 to MM 2.6.

Because additional grade change is not desirable, additional chemical additives will be needed to stabilize this area. For preliminary design purposes an assumed quantity of 6% cement should be used for this section of the roadway. An assumed quantity of 3% cement should be used for the rest of the project. Portions of the roadway with asphalt patches thicker than 6” were observed in several areas along CR 258. Due to the high cost of asphalt in the area, an alternative cost analysis of structural sections with cement additive vs an additional inch of HACP was performed. This analysis is available in Appendix G and showed a significant savings using a cement additive.

Due to higher R-values and lower traffic loads observed on the campground access road and campground loop, the cement additive may be omitted in these sections if desired.

If a realignment of CR 64 is required for rock fall mitigation, a replace in kind approach to the pavement section should be used. The following is the recommended pavement structural section:

Table 4: Recommended Pavement Section, Realignment, CR 64 Layer Thickness

HACP 4 inches (two lifts) Aggregate Base Course 6 inches

For the Blue Lake Trail a minimum structural section of 2” HACP (single lift) on 4” of ABC is recommended.

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 64-28M 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 the result of 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 5: Recommended Pay Items

Item Number Item Description Unit

20402-0000 Subexcavation CUYD

30202-2000 Roadway Aggregate, Method 2 TON

30502-0600 Full Depth Reclamation w/ Cement, 6-inch SQYD

30510-0000 Cementitious Material TON

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

40605-0000 Blotter TON

41101-1000 Prime Coat, Method 1 TON

41105-0000 Blotter TON

41201-0000 Tack Coat TON

Special Contract Requirements

CFLHD standard SCRs related to pavements and materials will be used. An SCR for the CalTrans PG 64-28M grading requirements should be included.

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

G – Alternative Cost Analysis

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

Liquid Limit /

Plasticity

Resistivity, ohm.cm pH Sulfate % Chloride %

0 to 5.25"

5.25" to 11.25"

11.25" to 4.2'

0 to 4"

4" to 10"

10" to 12"

10" to 4.5'

0 to 2"

2" to 6"

6" to 3'

3' to 5'

0 to 2.5"

2.5" to 6.5"

6.5" to 3'

3' to 5'

0 to 2"

2" to 7" 7" to 5'

0 to 2.25"

2.25" to 5'

0 to 3.25"

3.25" to 5'

0 to 3"

3" to 5'

0 to 3.25"

3.25" to 3' CH / A-7-6(11) 51 / 27 3' to 5'

0 to 3"

3" to 5'

0 to 2.5"

2.5" to 8.5"

8.5" to 4'"

4' to 5'

0 to 3"

3" to 7"

7" to 5'

0 to 3"

3" to 7"

7" to 2'

2' to 5'

0 to 2.75"

2.75" to 6.75"

6.75" to 5'

0 to 3"

3" to 7"

7" to 5'

0 to 2.75"

2.75" to 6.75"

78 GM / A-1-b(0)

SM / A-2-4(0)

Sand Clayey, Brown, Moist Gravel Clayey w/ Cobbles, Brown

Aggregate Base Course, Brown Sand Clayey, Brown, Moist

3" / 0" 1,190 7.2 0.006 0.0010

SC / A-2-6(0)

11/5/2019 5-gal bucket

P-8 1.8 Mi S of

CR 64

4' LT 11/4/2019 5'

5-gal bucket

Asphalt

P-11 2.8 Mi S of

CR 64

P-9 2.1 Mi S of

CR 64

Sand Clayey, Brown, Slightly Moist Aggregate Base Course, Brown

Gravel Clayey, Brown

Sand Clayey, Brown

5-gal bucket

Asphalt

Classification

5-gal bucket

Classification, R-Value, Resistivity, pH, Sulfates, and Chlorides

3.5" RT 11/4/2019 5'

5-gal bucket

Asphalt

3" / 4"

11/5/2019 5' 5-gal bucket

Aggregate Base Course, Brown Clay Sandy, Brown, Slightly Moist

0.0007

1,920 7.9 0.005 0.001347 / 23CL / A-7-6(11)

Mobile B80 truck mounted drill rig (8"O.D. HSA)

Diamond Core Drilling Pavement Investigation - Shallow Borings and Cores - Log & Sampling Summary

0.0007

0.0006

0.004

0.004

0.004

6.7

7.7

7.2

7.3

4,240

5,240

1,660

3,320

2.75" / 4"

2.25" / 0"

3.25" / 0"

3.25" / 0"

3" / 0"

2.5" / 6"

3" / 4"

2.75" / 4"

3" / 4"

SC / A-2-6(0)

SC / A-7-6(9)

34 / 9

< 5 SC / A-7-6(7)

4' RT 11/4/2019 5'

5-gal bucket

Asphalt ClassificationSand Silty, Brown, Moist

P-2 CR 64, MM

8.3

3.5' RT,

EB

11/4/2019 5' 5-gal bucket

Asphalt Classification, R-Value, Resistivity, pH, Sulfates, and Chlorides

Refusal at 4.5' Aggregate Base Course, Brown

Gravel Silty, Redish Brown, Moist

P-4 0.5 Mi S of

CR 64

4' LT 11/4/2019

Asphalt Aggregate Base Course, Brown Sand Clayey, Brown, Moist

Classification, and R- Value

5'

P-6

P-5

1.1 Mi S of

CR 64

5-gal bucket

Asphalt

3.5' RT

0.8 Mi S of

CR 64

Asphalt

Clay, Brown, Very Moist

ClassificationClay Sandy, Light Brown, Moist

P-7 1.5 Mi S of

CR 64

Comments

Refusal at 4.2'

Testing Requested

CA FLAP MOD 258(1) Blue Lake Road Contractor:

Logged By: Equipment:Sampled By:Marty Fey Marty Fey

11/4/20193' RT, EB

CR 64, MM

4.8

Boring Observations (grey = sample depth )

Asphalt Aggregate Base Course, Brown Sand Silty, Redish Brown, Moist

Asphalt

P-3 0.2 Mi S of

CR 64

4' RT 11/4/2019

5-gal bucket

11/4/2019

Gravel Clayey, Brown

5' 2.5" / 4"

2" / 5"

5' 5-gal bucket Classification 2" / 4"

5.25" / 6"

4" / 6"

Classification, R-Value, Resistivity, pH, Sulfates, and Chlorides

Classification, Resistivity, pH, Sulfates, and

Chlorides

Aggregate Base Course, Brown

Gravel Clayey, Brown

Sand (Cinders), Red, Moist

Asphalt Classification

Aggregate Base Course, Brown

Sand Clayey, Brown, Moist

Aggregate Base Course, Brown Sand Clayey w/ Cobbles, Brown

Asphalt

Sand Clayey, Brown, Moist

None No Sample Taken

Classification

Classification, R-Value, Resistivity, pH, Sulfates, and Chlorides

Aggregate Base Course, Brown

Classification, R-Value, Resistivity, pH, Sulfates, and Chlorides Asphalt

ClassificationAggregate Base Course, Brown

3.5' RT 11/5/2019 5'

5-gal bucket

Asphalt

P-16 4.5 Mi S of

CR 64

P-15 4.1 Mi S of

CR 64

11/5/2019 5' 5-gal bucket

3' RT

3.5' LTP-14 3.8 Mi S of

CR 64

11/5/2019 5' 5-gal bucket

P-13 3.4 Mi S of

CR 64

P-10 2.5 Mi S of

CR 64

11/4/20193.5' LT 5'

P-12 3.1 Mi S of

CR 64

4' RT 11/5/2019 5'

5'

5' 5-gal bucket Classification4.5' LT

Asphalt Sand Clayey, Brown, Slightly Moist

Asphalt

4.5' LT

66 SC-SM / A-2-4(0) 26 / 7

26 / 3

P-1 5' 5-gal bucket

4' LT

11/4/2019

SC / A-6(3)

Sand Clayey, Brown, Moist

7 SC / A-7-6(7) 44 / 22

33 / 15

40 / 18

39 / 19SC / A-6(6)

49 / 30

SC / A-6(2) 33 / 16

33 / 15

56 / 38

45 / 27SC / A-7-6(5)

53 / 29SC / A-7-6(11)

Sample Number

Station or Location

Offset from CL

Date Sampled

Depth of Bore

Container Type

Pavement/ABC Thickness R-Value Class

Liquid Limit /

Plasticity

Resistivity, ohm.cm pH Sulfate % Chloride %CommentsTesting RequestedBoring Observations (grey = sample depth )

6.75" to 5'

0 to 2.75"

2.75" to 6.75"

6.75" to 5'

0 to 2.75"

2.75" to 6.75"

6.75" to 3'

0 to 2.5"

2.5" to 5.5"

5.5" to 5'

0 to 2.75"

2.75" to 6.75"

6.75" to 5'

0 to 3"

3" to 7"

7" to 5'

0 to 2.75"

2.75" to 5.75" 12 5.75" to 10'

Aggregate Base Course, Brown Sand Clayey w/ Cobbles, Brown

P-20 5.7 Mi S of

CR 64

4' LT Refusal at 3.5'

P-18 5.1 Mi S of

CR 64

4' LT 11/5/2019

Refusal at 3', No Sample

Taken bucket

11/5/2019 5' 5-gal bucket

Asphalt Classification

2.5" / 3"

3" / 4"

2.75" / 3"

0.0013

0.0010

0.004

0.003

7.8

7.2

3,510

3,650

2.75" / 4"

2.75" / 4"

2.75" / 4"

Aggregate Base Course, Brown Sand Clayey, Reddish Brown

P-22 6.4 Mi S of

CR 64

5' RT 11/5/2019 10'

5-gal bucket

Asphalt Classification, R-Value, Resistivity, pH, Sulfates, and Chlorides Aggregate Base Course, Brown Sand Clayey, Soft, Brown

5-gal bucket

Classification, R-Value, Resistivity, pH, Sulfates, and Chlorides P-19

P-21 Classification

Aggregate Base Course, Brown Silt Sandy, Brown

4.5' RT

11/5/2019 3.5' 5-gal bucket

Asphalt ClassificationAggregate Base Course, Brown

Sand Clayey w/ Cobbles, Brown

3.5' RT 11/5/2019

3' 5-gal bucket

Asphalt None

4.8 Mi S of

CR 64

5' Aggregate Base Course, Brown Sand Clayey w/ Cobbles, Brown

5.4 Mi S of

6.1 Mi S of

CR 64

4' RT 11/5/2019

P-17

Asphalt

Sand Clayey w/ Cobbles, Brown

5' 5-gal bucket

Asphalt

SC / A-2-6(1) 32 /14

SC / A-6(1) 31 /12

SC / A-7-6(2) 44 /20

MH / A-7-5(15) 79 / 32

SC / A-6(4) 39 / 18

N W Elev.

P-1 3' RT EB 41.229862 -120.415587

P-2 3.5' RT EB 41.234884 -120.354860

P-3 4' RT 41.232971 -120.337164

P-4 4' LT 41.227841 -120.338160

P-5 3.5' RT 41.223613 -120.336586

P-6 4.5' LT 41.218756 -120.331310

P-7 4' RT 41.216032 -120.328799

P-8 4' LT 41.211629 -120.326764

P-9 3.5' RT 41.206106 -120.324436

P-10 3.5' LT 41.201985 -120.321761

P-11 4' RT 41.198708 -120.319280

P-12 4.5' LT 41.194278 -120.317218

P-13 3' RT 41.189726 -120.313911

P-14 3.5' LT 41.186966 -120.311981

P-15 3.5' RT 41.181480 -120.309325

P-16 4' LT 41.177977 -120.303282

P-17 4.5' RT 41.176653 -120.299844

P-18 4' LT 41.174609 -120.294040

P-19 3.5' RT 41.172243 -120.289704

P-20 4' LT 41.168819 -120.286008

P-21 4' RT 41.164792 -120.281875

P-22 5' RT 41.161351 -120.278662

CR 64, MM 4.8 Rockfall 1 CR 64, MM 8.3 Rockfall 2

MM 1.5

In area of roadway failure

Coordinates & Elevation Comments

CA FLAP MOD 258(1)

Blue Lake Road

Boring Locations

Boring Number

Mile Post & Lane

Appendix C: Photographs

Photo 1: Blue Lake Road, Typical Pavement

Photo 2: CR 64, Rock Fall 1

Photo 3: CR 64, Rock Fall 2

Photo 4: Blue Lake Road, P‐5, Pavement Damage

Photo 5: Blue Lake Road, P‐11

Photo 6: SPT Sampler

Photo 7: Blue Lake Road

Photo 8: Campground Access Road

Photo 9: Campground Access Road, Typical Pavement

Photo 10: Campground Access Road, Pavement Thickness

Photo 11: Blue Lake Boat Ramp

Photo 12: Campground Loop, Typical Pavement

Photo 13: Damage to Campground Loop.

Appendix D: AASHTO ’93 Flexible Pavement Design

AASHTO FLEXIBLE PAVEMENT DESIGN

Layer Thickness Determination Using Trial and Error

FDR w/out Cement

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

(topmost) Layer 1 AC Layer 0.44 1.00 4.00 1.76 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 2.48 403 = 0.40

CAB 301 = 0.14 Design SN to Match 2.52 Subbase/Minor agg 302 = 0.12 FDR 304 = 0.12 Error! Design is not 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)

Layer Thickness Determination Using Trial and Error

FDR w/ Cement

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 w/ Cement 0.20 1.00 6.00 1.20 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 2.52 403 = 0.40

CAB 301 = 0.14 Design SN to Match 2.52 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)

ADT 100 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 57.0% 0.0006 57 0 85 Values Pickups, Vans 32.0% 0.004 24.29737 32 681 48

149 (calculated) Class 4 buses 0.0% 1.5 24.29737 0 0 0 100 Class 5 trucks/RVs 10.0% 0.5 24.29737 10 26606 15

2018 Class 6 0.0% 1 24.29737 0 0 0 2038 Class 8 1.0% 1.5 24.29737 1 7982 1

2 Class 9 0.0% 2 24.29737 0 0 0 100.00% 35268 149

(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

R-Value = 14 S1 = 3.797 MR = 4060 R-Value = 5 S1 = 3.000 MR = 3025

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.

SN Determination

Design Inputs W18 = 50,000 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 = 3,500 psi Subgrade Resilient Modulus Typ. Range 3000 to 15000 psi

Pi = 4.2 Initial Serviceability Typ. Range 4.2 to 4.4

Pt = 2 Terminal Serviceability Typ. Range 2.0 to 3.0

DESIGN SN = 2.52

Appendix E: PG LTPPBind Software

BindReport‐5Closest.txt

Five Closest Weather Stations For Latitude/Longitude= 41.558/120.503 Report Date: 2/18/2020 (LTPPBind V3.0 Alpha)

CA FLAP MOD 258(1) Blue Lake Road

General A=8 km B=27 km C=32 km D=38 km E=46 km Station ID CA0161 CA1614 CA1476 CA4374 CA3157 County/District modoc modoc modoc modoc modoc Weather Station alturas cedarville canby ranger st jess valley fort bidwell Elevation, m 1246 1323 1220 1501 1274 Latitude, Longitude 41.5 ,120.55 41.53 ,120.17 41.45 ,120.87 41.27 ,120.3 41.85 ,120.13 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 35.3 (15,35) 34.3 (13,35) 34.8 (14,20) 32.4 (16,35) 33.4 (12,35) Low Temperature ‐23.8 (53,35) ‐19.1 (48,35) ‐25.1 (65,11) ‐21.3 (45,35) ‐20.4 (48,35) Low Temperature Drop 31.5 (28,35) 25.9 (24,35) 31.9 (27,11) 26.7 (30,35) 25.9 (27,35) Degree‐Days > 10C 2735 (241,35) 2585 (208,35) 2830 (241,20) 2341 (263,35) 2655 (209,35)

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

Pavement Temperature, C 54.3 ‐16.8 53.0 ‐13.5 55.1 ‐17.8 50.7 ‐15.0 53.6 ‐14.5 50% Reliability PG 58‐22 (98,88) 58‐16 (98,73) 58‐22 (98,79) 52‐16 (86,61) 58‐16 (98,64) >50% Reliability PG 58‐28 (98,98) 58‐22 (98,98) 58‐28 (98,97) 52‐22 (86,96) 58‐22 (98,96) = 58‐34 (98,98) 58‐22 (98,96) 58‐28 (98,98) = 58‐28 (98,98)

Appendix F: Preliminary Pavement Recommendations Memo

Subject: Preliminary Pavement & Materials Recommendations (V1)

From: Marty Fey Pavement & Materials Engineer, CFLHD

Through: Mike Voth Pavement & Materials Team Lead, CFLHD

To: Wendy Longley, Project Manager, CFLHD Sebastian Guzman, Design Engineer, CFLHD

INTRODUCTION

This memorandum provides preliminary pavement and material recommendations for the Blue Lake Road project located in Modoc National Forest, east of Likely, California.

Blue Lake Road, also known as CR 258 or Old Blue Lake Road, runs from the intersection of CR 64 on the north end of the project 6.5 miles south to the Blue Lake Campground turnoff. Two potential rock fall mitigation areas on CR 64 were also explored as part of this investigation.

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

There are multiple alternatives to consider for the pavement structural section of Blue Lake Road. We can meet at your convenience to discuss the pros and cons of each option.

FIELD INVESTIGATION

On November 4th and 5th, 2019 CFLHD pavement & material staff completed a field investigation which included boring and subgrade sampling. Diamond Core Drilling was hired through the CFLHD BPA to assist with the field investigation. A Mobile B80 truck-mounted drill rig with an 8” O.D. hollow stem auger was used to complete the borings. Pavement boring were logged at 20 locations along Blue Lake Road and at two locations on CR 64. Subgrade samples were collected and tested in the laboratory. See the attached boring and testing logs for more detailed information.

Technical Memorandum

Date: March 11, 2020

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;

Evaluate roadway and project area for constructability concerns.

For CR 258, 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.

CR 64 was paved by FHWA in 1995 and is performing well. Preventative maintenance has been performed including a recent chip seal.

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

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

Summary of Sampling & Test Results, CR 258

Pavement Depth

Roadbase Depth

R‐value, subgrade

Plasticity Index

Comments

2 to 3 ¼ inches

0 to 5 inches

<5 to 17 12 to 38

Subgrade material consists primarily of Clayey Sands, A‐6 and A‐7. Some high plasticity clays were also observed. Low subgrade R‐values indicate the material has very poor support characteristics and will require a thicker pavement section.

Resistivity values are low to moderate and indicate a potential increased risk of sulfate and chloride attack. Laboratory testing for chloride and sulfate content was performed and indicate a low risk.

Summary of Sampling & Test Results, CR 64

Pavement Depth

Roadbase Depth

R‐value, subgrade

Plasticity Index

Comments

4 to 5 ¼ inches

6 inches 66 to 78 3 to 7

Subgrade material consists of Silty Sands and Gravels, A‐2‐4(0) and A‐1‐b(0).

Practical refusal was encountered at both locations and depths of 4.2 and 4.5 feet.

TRAFFIC:

Traffic counts for CR 258 were provided with the FLAP application and used to developed estimates for ESALs. The road is primarily used for recreational 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 = 100

2039 ADT = 149 (2% growth rate) 2019 % trucks = 10% Class 5 (trucks/RVs), 1% Class 8 Directional factor = 60% Calculated Lane ESAL’s = 35,268 Design Lane ESAL’s = 50,000 (minimum required by AASHTO)

DESIGN RECOMMENDATIONS

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

In developing the pavement structural and rehabilitation recommendations for CR 258 the following criteria was used:

Design Criteria, CR 258 Initial Serviceability 4.2 Terminal Serviceability 2.0 Design Reliability Level 75% Overall Standard Deviation 0.49 Soil Resilient Modulus (average R-value = 10) 3,500 psi Performance Period (4R) 20 years 20-year ESAL 50,000 Calculated Structural Number (SN) 2.52

If a realignment of CR 64 is required for rock fall mitigation, a replace in kind approach to the pavement section should be used.

The following are the recommended pavement structural sections:

CR 258

Alternative A Alternative B

Layer Thickness Thickness HACP 3 inches (two lifts) 4 inches (two lifts) FDR w/ Cement 6 inches - FDR - 6 inches

SN 2.52 2.48

The pros and cons of the two options are detailed in the following table. I am available to set up a meeting at your convenience to further discuss the options. Given the cost differential and improved constructability, it is recommended to use Alternative A.

Alternative Section Considerations Delta Cost Time Constructability Alternative A $0 Requires additional cure time.

Stabilized soils can be driven on.

Alternative B $524,000 No wait for curing.

Soft soils may hinder operations, and lead to more subex.

No aggregate base course was observed under the pavement of CR 258 from MM 1.0 to MM 2.6.

The contractor will need to import aggregate roadbase and add it to the surface in this area prior to performing FDR to improve the stability of the resulting material. Alternatively, chemical additives may be used to stabilize the subgrade if addition grade change is not desirable.

Realignment, CR 64 Layer Thickness

HACP 4 inches (two lifts) Aggregate Base Course 6 inches

ADDITIONAL RECOMMENDATIONS:

The asphalt binder grade should be PG 64-28M. This aligns with recommendations from LTPPBind and local standards.

Include a nominal amount of subexcavation (~500 cu yd) 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” SQYD 30502-0600 Full Depth Reclamation w/ Cement, 6” SQYD

40101-5600 Asphalt Concrete Pavement, Gyratory Mix, ½” or ¾” Nominal Max Size Aggregate, 0.3 to < 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

The project is located in a mountainous area where cobbles and refusal were encountered during the subsurface investigation. The contractor should expect to encounter some cobbles during construction.

CFLHD standard SCR’s related to pavements & materials will be used. A SCR for item 304 FDR or 305 FDR w/ Cement will need to be developed to make the contractor aware of the need for additional roadbase in select areas. If the decision is made to use a local borrow source and/or develop a source, an SCR may need to be developed.

Appendix G: Alternative Cost Analysis

Additional alternative cost in excess of 3" hma on 6" abc.

One inch additional asphalt (304 - Mech Stabilized) FDR w/ Cement (305 - Chem Stabilized) 1" HMA x 6.65 mile x 20 feet 13,037 CY x 4% rate => 2184.75 cubic yards of HMA x 1.9602 ton / cy => 521.48 cy of cement * 1.82 ton /cy => 4282.55 Tons of HMA x $200 / Ton => 949.09 tons of cement * $350 / ton

$856,510 $332,183

145.2 pcf 1" 0.028 yd 4% rate

6.65 mile 11704 yd 135 pcf 20' 6.67 yd 350 / ton

2184.747 cy 6" .167 yd 436950 13,037

145.2 lb/cf * 27 cf/cy * .0005 ton/lb 135 pcf * 27 cf/cy *.0005 ton/lb

1.9602 ton / cy 1.82 ton / cy