CO_FLAP_SUM_91(1)_Fremont_Trail_-_Final_Pavement_Tech_Memo.pdf

Subject: Pavement & Materials Final Recommendations CO FLAP 91(1) Fremont Pass Trail

From: Mike Voth Pavement & Materials Engineer, CFLHD

To: John Knowles, Project Manager, CFLHD Kelly Terrell Prose, Highway Designer, CFLHD Kelly Keele, Highway Designer, CFLHD

INTRODUCTION

This memorandum provides pavement and material recommendations for the 3.2-mile multi-use trail project that starts near Copper Mountain and proceeds southerly and parallel to SH 91. At the end of the project, the trail reconnects with SR 91. One of the purposes of the project is to provide a paved trail that will allow bikers to bypass a particularly narrow section of SH 91. The project follows the existing bench of an abandoned railroad grade. There are plans for future phases that would extend the trail towards Leadville.

The attachments to this memorandum include photographs from the field investigation, dynamic cone penetrometer (DCP) testing data, LTPPBind software reports, and general climate information.

FIELD INVESTIGATION

A field investigation was completed on October 5, 2017. The purpose of the field investigation was to explore and characterize the subsurface conditions (top 2 to 3 feet) along the proposed alignment of the trail using the dynamic cone penetrometer (DCP). DCP testing was conducted in general conformance with ASTM D 6951, Use of the DCP in Shallow Pavement Applications.

The results of DCP testing were used to develop the recommended pavement structural section for the trail.

15 DCP tests were completed along the alignment of the trail at approximate intervals of 1000 feet. The average CBR of the DCP tests was 9 which equates approximately to an R-Value of

40. The CBR values ranged from 4 to 15. In general, the subgrade soil strength (at depths of 12 to 18 inches) is fair to good. Cobbles and boulders are common in the upper two feet of subgrade. During DCP testing, cobbles or boulders were hit at numerous locations. Refer to the geotechnical report for soil subgrade gradation and classification information. See the DCP test results in the attachments for more detailed results.

Technical Memorandum

Date: March 18, 2019

DESIGN RECOMMENDATIONS

The surfacing, base, design and other recommendations for the multi-use trail are included in this section.

The PDDM does not contain guidance or requirements for surfacing thickness of paved trails, but the minimum asphalt concrete pavement (ACP) thickness for new roadways is 2 inches.

FLH has successfully constructed numerous bike and pedestrian trails with 2 inches of ACP including projects in Bryce Canyon National Park, Grand Canyon National Park, and Grand Teton National Park. FLH has also successfully constructed numerous bike and pedestrian trails with 3 inches of ACP including projects in Lake Tahoe and Albuquerque.

The AASHTO Guide for the Development of Bicycle Facilities, the CalTrans Highway Design Manual, and guidance from Illinois DOT are good references for developing pavement structural sections for trails. The following are some key excerpts:

•CalTrans Highway Design Manual- On page 1000-11, bike path pavement structure guidance includes the following, “A minimum pavement thickness of 50 mm (2 inches) of asphalt is recommended”. No minimum for aggregate base is provided. The asphalt can be placed directly on prepared subgrade soil.

•AASHTO Guide for the Development of Bicycle Facilities- On page 5-25, surface structure recommendations are, “…the total pavement depth should typically be a minimum of 6 in. (150 mm), inclusive of the surface course (asphalt or Portland cement concrete) and the base course (typically an aggregate rock base).”

•Best Practices for Bicycle Trail Pavement Construction and Maintenance in Illinois- This report includes mechanistic analysis of stresses and strains to estimate the number of passes to failure. This is a good resource and was used as a reasonableness check and to generate recommended base and surfacing thickness.

Using the Illinois Best Practices approach, the trail structural capacity was designed for regular duty traffic. Regular duty traffic includes trucks used for maintenance such as one-ton trucks (Ford F-350), as well as emergency vehicles and utility vehicles. For the aggregate base design, the following parameters were used: CBR value of 9, and high construction traffic factor. A high construction traffic factor was used because the proposed trail will be the primary means for site access and hauling of materials.

The following pavement structure is recommended for the multi-use trail:

3 inches ACP (40301-0100 type 1, less than 4000 tons) 4 inches of Aggregate Base (30202-2000 method 2, less than 8000 tons)

Much of the proposed alignment of the trail will be raised in elevation using unclassified borrow.

This will provide additional cover over the subgrade and further justifies the placement of a minimal thickness base layer.

For the aggregate pullout sections/rest areas, it is recommended to use a 6-inch layer of aggregate base as the surfacing material.

ADDITIONAL MATERIAL RECOMMENDATIONS:

• Tack coat (41201-1000) for application between ACP lifts.

• Prime coat (41102-1000, method 1) will be applied to all base material.

• Blotter (41105-0000) for use with prime coat, if needed.

• Given the high elevation of the project and the concern for thermal cracking, it is recommended to specify a PG graded asphalt even though we are using a 403 mix due to small quantities. It is recommended to use a PG 58-34 binder. This binder is used by the Colorado DOT and several suppliers can provide this grade. The PG 58-34 grade meets or exceeds the recommended grades provided by the LTPPBind software for the project location. It is also recommended to specify a maximum nominal size aggregate of ½ inch for the ACP mix. This should result in a more optimal surface texture for both pedestrians and bicycles.

CONSTRUCTION CONSIDERATIONS & SPECIAL CONTRACT PROVISIONS

For the most part, our standard SCRs as related to pavements & materials will be used.

However, the following SCR is recommended and has been provided:

Section 403 – Inclusion of PG 58-34 grade asphalt and ½ inch NMA size requirement.

ATTACHMENTS

Field Investigation Photographs

DCP Data Summary

LTPPBind Software Report

General Climate Data

~STA 15+50

~STA 24+00

Site Photos

~STA 34+00

STA 34+00

~STA 34+00

~STA 120+00

DCP TEST DATA

File Name:

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 2+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 250 1

5 330 1

5 399 1

5 461 1

5 498 1

5 536 1

5 591 1

5 622 1

5 645 1

10 697 1

10 718 1

Refusal: 1

19" 1

Rocks 1

Cobbles 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 2000 4000 6000 8000 10000 12000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

All other soils

Hammer

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 15+50 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 245 1

5 382 1

5 647 1

5 702 1

5 791 1

5 863 1 soft 1

Cobble @ 1

702mm 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 1000 2000 3000 4000 5000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 24+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 259 1

5 436 1

5 502 1

5 549 1

5 586 1

5 600 1 cobble @ 1

586mm 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 2000 4000 6000 8000 10000 12000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 34+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 255 1

5 372 1

5 430 1

5 468 1

5 515 1

5 539 1

5 570 1

5 629 1

5 667 1

5 710 1

Refusal: 1

18 inches 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 1000 2000 3000 4000 5000 6000 7000 8000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 53+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 251 1

5 435 1

5 490 1

5 532 1

5 593 1

5 670 1

5 743 1 cobble @ 1

490 mm 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 1000 2000 3000 4000 5000 6000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 68+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 259 1

5 355 1

5 424 1

5 512 1

5 550 1

5 600 1

5 620 1 cobbles 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 2000 4000 6000 8000 10000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 77+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 259 1

5 264 1

5 273 1

5 288 1

5 291 1

Refusal: 1

2 inces 1 lots of 1 cobbles 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

-120000 -100000 -80000 -60000 -40000 -20000 0 20000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 99+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 255 1

5 322 1

5 363 1

5 407 1

5 410 1

Refusal: 1

6 inches 1 lots of 1 cobbles 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

-120000 -100000 -80000 -60000 -40000 -20000 0 20000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 110+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 260 1

5 345 1

5 395 1

5 455 1

5 504 1

5 560 1

5 631 1

5 659 1 cobble @ 1

659 mm 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 1000 2000 3000 4000 5000 6000 7000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 120+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 249 1

5 340 1

5 392 1

5 448 1

5 473 1

5 504 1

5 532 1

5 560 1 cobble @ 1

560 mm 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 1000 2000 3000 4000 5000 6000 7000 8000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 129+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 263 1

5 346 1

5 378 1

5 411 1

5 439 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 1000 2000 3000 4000 5000 6000 7000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 140+00 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 259 1

5 392 1

5 486 1

5 555 1

5 656 1

5 718 1 cobbles 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 500 1000 1500 2000 2500 3000 3500 4000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 148+20 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 274 1

5 327 1

5 415 1

5 515 1

5 575 1

5 639 1

5 690 1

5 710 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 2000 4000 6000 8000 10000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 154+40 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 272 1

5 419 1

5 443 1

5 501 1

5 585 1

5 648 1

5 683 1

5 713 1 cobbles 1 at 443mm 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 1000 2000 3000 4000 5000 6000 7000 8000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

Project: CO FLAP SUM 91(1) Date: 5-Oct-17 Location: ~STA 160+30 Soil Type(s): Type in the soil type

No. of Accumulative Type of Blows Penetration Hammer

(mm)

0 271 1

5 438 1

5 498 1

5 532 1

5 555 1

5 575 1

Refusal 1

12 inches 1

0.1 1.0 10.0 100.0

0.1 1.0 10.0 100.0

D E

P T

H in

CBR

D E

P T

H m m

0 2000 4000 6000 8000 10000

D E

P T

H in

BEARING CAPACITY, psf

Based on approximate interrelationships of CBR and Bearing values (Design of Concrete Airport Pavement, Portland

Cement Association, page 8, 1955)

10.1 lbs.

17.6 lbs.

Both hammers used

Soil Type

CH

CL

BindReport‐5Closest CO FLAP SUM 91(1).txt

Five Closest Weather Stations For Latitude/Longitude= 39.454/106.266 Report Date: 3/20/2019 (LTPPBind V3.0 Alpha)

Fremont Pass Trail ‐ Near by Weather Stations

General A=13 km B=26 km C=27 km D=29 km E=41 km Station ID CO1660 CO8064 CO4885 CO2281 CO5507 County/District lake lake lake summit pitkin Weather Station climax sugarloaf reser leadville lake dillon 1 e meredith Elevation, m 3207 2759 2814 2568 2217 Latitude, Longitude 39.37 ,106.17 39.25 ,106.37 39.23 ,106.32 39.63 ,106.03 39.37 ,106.75 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 21 (17,34) 24.3 (15,30) 24.5 (13,17) 25.9 (12,35) 29.9 (12,28) Low Temperature ‐30.4 (29,35) ‐31.2 (53,29) ‐30.5 (35,17) ‐31.2 (34,35) ‐29.9 (34,29) Low Temperature Drop 27.5 (32,35) 30.1 (37,29) 28.3 (21,17) 29.9 (24,35) 30.8 (26,29) Degree‐Days > 10C 761 (139,34) 1274 (159,30) 1328 (90,17) 1527 (142,35) 2083 (153,28)

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

Pavement Temperature, C 33.3 ‐20.9 39.5 ‐21.4 40.1 ‐20.9 42.3 ‐21.6 48.2 ‐20.5 50% Reliability PG 40‐22 (98,65) 40‐22 (76,55) 46‐22 (98,63) 46‐22 (98,56) 52‐22 (98,68) >50% Reliability PG 40‐28 (98,98) 40‐28 (76,93) 46‐28 (98,98) 46‐28 (98,97) 52‐28 (98,98) = 46‐28 (98,93) 46‐34 (98,98) = 46‐34 (98,98)

Climate Leadville - Colorado

°C | °F Jan Feb Mar Apr May Jun

Average high in °F: 31 33 38 44 55 67

Average low in °F: 3 5 11 19 28 34

Av. precipitation in inch: 0.63 0.79 0.94 1.06 0.63 0.79

Days with precipitation: - - - - - -

Hours of sunshine: - - - - - -

Jul Aug Sep Oct Nov Dec

Average high in °F: 71 69 62 51 38 31

Average low in °F: 38 38 31 23 12 4

Av. precipitation in inch: 1.77 1.77 0.91 0.75 0.79 0.75

Days with precipitation: - - - - - -

Hours of sunshine: - - - - - -https://www.usclimatedata.com/climate/leadville/colorado/united-states/usco0235 https://www.usclimatedata.com/climate/leadville/colorado/united-states/usco0235