2010_Aug_6_Final_Pavement_Report_Rio_Blanco_CR_5.pdf

FINAL

Geotechnical Investigation and

Pavement Design

County Road 5 (Piceance Creek Road)

Rio Blanco County, Colorado

Project No. 29-202 August 6, 2010

Prepared for:

Rio Blanco County

Mr. Bahram Seifipour, P.E.

HDR Engineering 303 East 17th Avenue, Suite 700

Denver, Colorado 80203-1256

Prepared by:

Yeh and Associates, Inc.

170 Mel Ray Road

Glenwood Springs, Colorado 81601 Phone: 970-384-1500 Fax: 970-384-1501

Rio Blanco County Road 5 Project No. 29-202 i

TABLE OF CONTENTS

PURPOSE AND SCOPE

PROPOSED CONSTRUCTION

SITE CONDITIONS

SITE GEOLOGY

SUBSURFACE INVESTIGATION

SUBSURFACE CONDITIONS

Existing Asphalt

SITE DEVELOPMENT

PRELIMINARY FOUNDATION CONDITIONS

Bridge Foundations (White River)

Box Culvert Foundations (Fourteen Mile & Piceance Creeks and Jessup Gulch)

PAVEMENT DESIGN

Segment Sections

Subgrade Materials

Traffic Loading

Determination of Resilient Modulus (MR) of Subgrade for Design

New Alignment Hot Mix Asphalt Pavement Design

Rehabilitation Hot Mix Asphalt Pavement Design

Hot Mix Asphalt Type

Subgrade Preparation

Drainage Considerations

WATER SOLUBLE SULFATE

LIMITATIONS

Figures

Figure 1 – Site Location Figures 2 through 18 – Approximate Test Hole Locations

Appendices Appendix A – Logs and Legend of Exploratory Borings Appendix B – Laboratory Test Results Summary of Laboratory Test Results Table Appendix C – Pavement Design

Rio Blanco County Road 5 Project No. 29-202 ii

Rio Blanco County Road 5 Project No. 29-202

PURPOSE AND SCOPE

This report presents the results of our geotechnical investigation for proposed road improvements on County Road 5 (Piceance Creek Road) in Rio Blanco County, Colorado

(Figure 1). The purpose of this study was to evaluate geotechnical characteristics of the onsite soils and pavement subgrade and to provide geotechnical recommendations for pavements, preliminary geotechnical recommendations for culverts and bridge foundations and other geotechnical issues at the subject site.

The site investigation consisted of geologic reconnaissance and exploratory test hole drilling to investigate subsurface conditions. Test hole drilling was observed by a representative of Yeh and Associates. Samples obtained during the field exploration were examined by the project personnel and representative samples were subjected to laboratory testing to determine the engineering characteristics of materials encountered.

Based on our investigation, Yeh and Associates completed an engineering analysis of the subsurface conditions. We reviewed subsurface information (test hole logs and laboratory data) in the two previous investigations listed below performed by CTL|Thompson. Our report summarizes our field investigation, the test hole logs from CTL|Thompson, the results of our analysis, and our conclusions and recommendations based on the proposed construction, site reconnaissance, subsurface investigation, and results of the laboratory testing. We also reviewed the traffic study by RPI Consulting during preparation of our report.

“Preliminary Geotechnical Investigation and Pavement Report” by

CTL|Thompson, Inc., Project No. GS 05270-115, dated March 23, 2009.

“Preliminary Geologic Hazard Investigation” by CTL|Thompson, Inc., Project No.

GS 05270-115, dated January 15, 2009.

“Road and Bridge Department Impact Fee Support Study” by RPI Consulting, LLC, Final Report dated April, 2008.

PROPOSED CONSTRUCTION

The project consisted of widening, repaving, intersection improvements and reconstruction of several structures for approximately 42 miles of County Road 5 (Piceance

Creek Road) Mile Post 0.0 to 42+ from State Highway 13 to State Highway 64. We understood that proposed construction would include, but not limited to, seven intersections, five major

Rio Blanco County Road 5 Project No. 29-202 structures and the reconstruction of the roadway. Planned roadway widths will vary between 36 and 52 feet based on sections provided by Rio Blanco County.

Plans indicate County Road 5 will be rehabilitated for the entire 42 mile roadway. To accommodate heavier truck traffic and spring time load restrictions, a new roadway section will likely be constructed. Widening of the existing roadway may include medians, acceleration/deceleration lanes, left turn lanes and shoulders. At the time of investigation, new alignments, plans and profiles, cuts and fills were not provided.

The seven major intersections include State Highway 13 (Mile Marker 0), Sprague Gulch

Road (Mile Marker 12), County Road 3 (Mile Marker 18), MTW Ranch (Mile Marker 20), County

Road 26 (Mile Marker 23.5), County Road 24 (Mile Marker 27) and State Highway 64 (Mile

Marker 42). Intersection upgrades would likely include acceleration/deceleration lanes, turn lanes, medians, increased sight distances, turning radii and additional lanes. Grading plans were not provided and we anticipate cut and/or fill slopes may be necessary for planned improvements.

Five major structures are planned to be upgraded or reconstructed, include box culverts at Fourteen Mile Creek (Mile Marker 8.8), Jessup Gulch (Mile Marker 15.9), Piceance Creek

(Mile Markers 32 and 40) and the bridge across the White River (Mile Marker 41.8).

Reconstruction may include the replacement of existing culverts with wider, deeper structures.

Our understanding for the planned construction for the bridge over the White River may include complete demo and reconstruction or possibly widening the existing bridge with new bridge deck. The above structure locations were provided by the client.

SITE CONDITIONS

County Road 5 was paved at the time of investigation. Existing road widths vary between approximately 24 and 32 feet. Existing pavement appeared to be in satisfactory condition. Longitudinal and transverse cracks were observed at varying locations particularly in the northern section of this road. The cracking appeared to be minor and was previously filled.

Existing grades on County Road 5 vary between flat and 7 percent that generally slope down to the south and east. The roadway generally follows the Piceance Creek drainage and is generally located at the base of very steep to near vertical slopes at the transition to the valley

Rio Blanco County Road 5 Project No. 29-202 floor. A majority of the roadway appeared to be constructed by utilizing cut slopes on the uphill side and embankment fill slopes on the downhill side. Ranches, vacant land and gas/oil production access roads were located along the project site.

SITE GEOLOGY

The project area is located in the Piceance Basin of western Colorado, a complex of numerous anticlines and synclines and a major gas production area. The Piceance Basin is located in the Colorado Plateau province and the topography of the basin is made up of high plateaus and ridges and deep valleys. The asymmetrical, arc-shaped basin is about 100 miles long by 50 miles wide, is oriented northwest-southeast and is deepest on the east edge. It is bounded structurally on the north by the Uinta Mountains, on the northeast by the Axial Uplift, on the east by the Grand Hogback/White River Uplift and the Elk Mountains, on the south by the

Uncompahgre Uplift and on the west by the Douglas Creek Arch/Rangely Dome. Exposed in the project area are Tertiary age sedimentary rocks including the brown and gray sandstone, siltstone and marlstone of the Uinta Formation and the upper members of the Green River

Formation, which includes localized layers of marlstone, siltstone, and sandstone. Bedrock is exposed in the project area in slopes and cliffs adjacent to the roadway. Surficial deposits include colluvium and alluvial gravels and artificial fill. Possible geohazards in the project area include, but are not limited to, rockfall, expansive and/or collapsible soils, subsidence, hydrocompaction, and debris flow. The scope for this investigation did not include evaluation of geologic hazards for this site.

SUBSURFACE INVESTIGATION

The client requested test hole drilling approximately every mile for the entire 42 mile length. Utilizing information from the previous investigation by CTL|Thompson, we drilled additional test holes to meet the clients request for a test hole every mile. Our investigation consisted of drilling 40 additional test holes. Test holes YA-1 through YA-32 were drilled to investigate existing pavement and subgrade materials. Test holes YA-31 and YA-32 were also drilled to obtain subsurface conditions at the bridge across the White River. Test holes YA-33 through YA-40 were drilled at existing culvert structures. The locations of the test holes are presented on Figures 2 through 18 in appendix A. Test hole depths varied between 10 and 49 feet. Pavement test holes were drilled through existing pavement. All test holes were advanced using either a CME 45 or Dietrich D50 drill rig with 4-inch continuous flight auger to pre-

Rio Blanco County Road 5 Project No. 29-202 determined depths where a modified California or split spoon sampler was used to record blow counts and obtain samples. Bulk samples were also obtained at depths indicated.

To perform the modified California penetration resistance tests, a 2.0-inch inside diameter sampler was seated at the bottom of the test hole, then driven up to 12 inches with blows of an standard hammer weighing 140 pounds and falling a distance of 30 inches utilizing a “auto hammer” or “cat’s head” (ASTM D1586). The number of blows (Blow Count) required to drive the sampler 12 inches or a fraction thereof, constitutes the N-value. The N-value, when properly evaluated, is an index of the consistency or relative density of the material tested. Split spoon samples are obtained in the same manner, but with a 1.5-inch inside diameter sampler.

Test hole logs and legend are presented in Appendix A.

SUBSURFACE CONDITIONS

Subsoils encountered in the test holes consisted of varying amounts of existing asphalt over a sand with gravel layer underlain by fill, sand, gravel, silt and/or clay. Weathered to hard sandstone bedrock was encountered within three feet of the surface in test holes YA-3, YA-19 and YA-23. Claystone bedrock was encountered in test hole YA -31 and test hole YA -32 and sandstone bedrock in YA -37 at depths of 26 feet, 23 feet and 42 feet, respectively.

Rio Blanco County Road 5 Project No. 29-202

Existing Asphalt Pavement

All test holes were drilled on existing pavement and existing sections measured. On average, existing asphalt consisted of 9 inches. Asphalt and base thicknesses measured during our investigation are presented in Table 1.

Segment 1 MP 0.0 to 12

Segment 2 MP 12 to 23

Segment 3 MP 23 to 34

Segment 4 MP 34 to 41

Table 1 – Existing Pavement Sections

Test Hole Asphalt (inches)

Base or Chip Seal (inches)

YA-1 17 4

YA-2 10 7

YA-3 7 4

YA-4 7 8

YA-5 11 4

YA-6 11 6

YA-7 11 6

YA-8 11 6

YA-9 11 6

YA-10 11 6

YA-11 11 12

YA-12 11 6

YA-13 11 12

YA-14 11 12

YA-15 11 12

YA-16 11 12

YA-17 11 12

YA-18 11 12

YA-19 10 6

YA-20 11 6

YA-21 10 6

YA-22 10 6

YA-23 10 6

YA-24 5 6

YA-25 6 6

YA-26 5 6

YA-27 8 4

YA-28 8 6

YA-29 10 6

YA-30 6 6

YA-31 7 12

YA-32 7 12

YA-33 9 12

YA-34 10 9

YA-35 6 10

YA-36 4 7

YA-37 6 9

YA-38 6 13

YA-39 8 6

YA-40 4 10

Rio Blanco County Road 5 Project No. 29-202

Existing Base or Chip Seal Material

Samples of the granular layer beneath the existing asphalt were subjected to laboratory testing. On average, this granular layer was 8 inches thick (See Table 1). A sample from test hole YA-33 had 2 percent fines (material passing the No. 200 sieve). This sample classified as a SP based on the Unified Soil Classification System (USCS) and an A-1-a based on the

American Association of State Highway Transportation Officials (AASHTO). One Hveem R-value test (ASTM 2844) was performed on a composite sample from test holes YA-35 and YA -

40. The result indicated a R-value of 75 at an exudation pressure of 300 psi. Complete test results of laboratory testing are found in Appendix B and are summarized in the Summary of

Laboratory Test Results.

Existing Fill

Twenty four fill samples were subjected to laboratory testing. The existing fill consisted of gravel, sand, silt and clay. Eighteen gravel and sand fill samples tested had 11 to 47 percent fines. Atterberg limit testing on these samples exhibited liquid limits of non-liquid to 33 percent and plastic indices of non-plastic to 16 percent. One clayey sand fill sample exhibited a low swell of 0.1 percent when wetted under an applied load of 1,000 psf. Six silt and clay fill samples had 55 to 74 percent fines, liquid limits of non-liquid to 31 percent and plastic indices of non-plastic to 13 percent. One sandy, silt fill sample exhibited a low swell of 0.2 percent. Fill samples classified as GM, SM, SC, CL and CL-ML (USCS) and A-1, A-2, A-4 and A-6

(AASHTO).

We believe that existing fill was constructed by cut and fill methods for original roadway construction and may have been placed in an uncontrolled manner. Typically, any uncontrolled fill under planned improvements should be moisture conditioned and recompacted. However, we believe the existing fill below new pavements should not result in poor pavement performance.

Sand and Gravel

Thirty-two sand and gravel samples were subjected to laboratory testing. Testing indicated 4 to 49 percent fines, liquid limits of non-liquid to 37 percent and plastic indices of non-plastic to 17 percent. Two samples tested exhibited low compression to low swell (-0.1 and 0.8 percent) when wetted under an applied pressure of 1,000 psf. These sand samples were silty

Rio Blanco County Road 5 Project No. 29-202 sand and clayey sand, respectively. The gravel and sand classified as GP-GM, GM, SM and

SC (USCS) and A-1, A-2, A-4 and A-6 (AASHTO).

Silt and Clay

Seven silt and clay samples were subjected to laboratory testing. Testing indicated 52 to 81 percent fines, liquid limits of non-liquid to 44 percent and plastic indices of non-plastic to

22 percent. Three samples exhibited no movement to low compression (0.0, -0.3 and -0.4 percent) when wetted under an applied pressure of 1,000 psf. The silt and clay classified as ML and CL (USCS) and A-4, A-6 and A-7 (AASHTO).

Bedrock

Three sandstone bedrock and two claystone bedrock samples were tested. Testing indicated sandstone samples had 7 to 13 percent fines and were non-plastic and non-liquid.

Testing indicated claystone samples had 84 to 90 percent fines, liquid limits of 32 and 46 percent and plastic indices of 19 and 27 percent. The sandstone classified as an A-1 and the claystone as A-6 and A-7 (AASHTO).

Groundwater

Groundwater was encountered during drilling at a depth 16 feet in YA-12 and between

12 and 17.5 feet in test holes YA -32 through YA -40. All other test holes were dry. The test holes were backfilled at drilling.

Groundwater will likely be encountered during foundation construction at the culvert and bridge locations. Dewatering and/or diversion may be required in these areas prior to and during construction. Variations in groundwater conditions may occur seasonally. The magnitude of the variation will be largely dependent upon the amount of spring snowmelt, duration and intensity of precipitation, site grading changes, and the surface and subsurface drainage characteristics of the surrounding area.

SITE DEVELOPMENT

Proposed alignments, plans and profiles, proposed cuts and fills were not provided at the time of investigation. We believe construction may include intersection upgrades, upgrade or reconstruction of structures and new pavements. Upgrades may include widening of roadways for shoulders, medians and turn lanes. We anticipate fill placement would be required

Rio Blanco County Road 5 Project No. 29-202 for roadway widening and structure upgrades. We anticipate rock and/or soil cut slopes may also be necessary for widening or realignment. We anticipate cut slopes in soil may be excavated with conventional equipment. Bedrock cut slopes would likely require heavier equipment, rock-splitting and/or blasting. On-site soils and bedrock could be used in site grading fills. We recommend the materials be processed to a maximum particle size of 6 inches.

Areas to receive fill should be stripped of vegetation, organic soils and debris. Topsoil is not recommended for fill material. Fill should be placed in thin, loose lifts of 8 inches thick or less. The on-site soils free of organic matter, debris and rocks larger than 6 inches can be used in fills. We recommend fill materials be moisture conditioned to within 2 percent of optimum moisture content and compacted to at least 95 percent of maximum standard Proctor dry density (ASTM D 698). For fill below a depth of 15 feet, we recommend the materials be moisture conditioned within 2 percent of optimum moisture content and compacted to at least

100 percent of maximum standard Proctor dry density (ASTM D 698). Placement and compaction of fill should be observed and tested by a representative of the geotechnical engineer.

We recommend that permanent soil cut slopes be constructed at a slope no steeper than 2H:1V. Temporary excavation slopes should be constructed no steeper than 1H:1V.

Permanent cut slopes in bedrock can be constructed at a 3/4H:1V. Permanent bedrock cut slopes may be constructed steeper on a case by case study after inspection and characterization of the bedrock by the geotechnical engineer. Permanent fill slopes should be constructed no steeper than 2.5H:1V. If fill slopes are planned steeper than 2.5H:1V, the slopes should be evaluated for stability and may require the installation of a retaining wall system or constructed as a geogrid reinforced soil slope (RSS). Surface water should be directed away from the crest of slopes. The slopes should be protected from erosion by revegetation or other means. The risk of slope instability increases if seepage is encountered in cut slopes. Flatter slopes may be required if significant seepage is encountered in cut slopes.

Prior to fill placement, we believe that all fills placed on slopes or existing embankments steeper than 4H:1V, should be “benched”. We recommend the slopes be benched prior to fill placed as recommended in the 2005 CDOT Standard Specifications section 203.06. Benching shall be well keyed and, where practical, a minimum bench width of 8 feet should be

Rio Blanco County Road 5 Project No. 29-202 constructed. Each horizontal cut shall begin at the intersection of the original ground and the vertical sides of the previous bench.

PRELIMINARY FOUNDATION CONDITIONS

A total of 10 test holes were drilled for preliminary foundation conditions at five locations along County Road 5. Test holes YA-31 (south abutment) and YA-32 (north abutment) were drilled for the planned bridge reconstruction across the White River and test holes YA-33 through YA-40 were drilled for new box culverts at Fourteen Mile Creek, Jessup Gulch and

Piceance Creek (2 locations). For culvert replacements, odd numbered test holes were drilled on the west or north abutments and even test holes drilled on the east or south abutments. All test holes were drilled on existing pavement. Preliminary foundation conditions are presented below.

Bridge Foundations (White River)

Due to soft, lower bearing capacity near surface soils, we believe the bridge should be supported on a driven pile or micropile foundation. We believe the piles could be founded in the dense cobble and boulder material or in the bedrock. For the cobble/boulder material, we recommend a tip elevation for driven piles and beginning bond elevation for micropiles at about elevation 5725 to 5727 feet. For foundations supported in bedrock, we recommend a tip elevation for driven piles and beginning bond elevation for micropiles of about elevation 5711 to

5716 feet. Groundwater will likely be encountered at about elevation 5726 feet. Groundwater control measures such as casing may be required for installation of predrilled driven piles or micropiles. Typically, micropiles are designed and installed by a specialty contractor.

Box Culvert Foundations (Fourteen Mile Creek, Piceance Creek and Jessup Gulch)

Due to soft, saturated, lower bearing capacity clay and sand soils at anticipated footing depths, we believe foundation movement could occur for heavily loaded structures due to these soils. Footing or mat foundations for existing conditions could be designed for a maximum allowable soil pressure of between 1,000 and 2,000 psf. If proposed foundation loads exceed these estimates, foundation soils would likely require subexcavation and replacement as discussed below.

To reduce the risk of potential movement, we anticipate removal and replacement of the on-site soils to depths on the order of 1 to 3 feet below foundation levels. The subexcavation

Rio Blanco County Road 5 Project No. 29-202 area would likely extend at least 2 to 5 feet beyond the edge of footings or box culvert foundations. We anticipate a structural fill such as a CDOT Class 1 or CDOT Class 6 roadbase material would be required in the subexcavation. A separator fabric and/or geogrid reinforcement may also be required in the subexcavated fill section. For subexcavated foundation soils, we anticipate maximum allowable soil pressures on the order of 2,500 to 3,500 psf. Groundwater was encountered at the culvert locations during our investigation.

Dewatering and/or groundwater diversion will likely be required for subexcavation and foundation construction.

PAVEMENT DESIGN

A pavement section is a layered structure designed to disperse dynamic traffic loads to the subgrade. The performance of the pavement structure depends on the traffic loadings and physical properties of the subgrade materials. As described below, soils are represented for flexible pavement design purposes by means of a soil support value that is empirically related to strength. Based on traffic volumes provided by Rio Blanco County, we divided the roadway into four segments with similar traffic values. The segment locations are discussed below.

Segment Sections

Using current volumes and based on a 2.2 percent growth, we estimated the project weekly traffic volumes for a 20 year design. Based on the projected volumes, the roadway was divided into four segments based on similar traffic loading and subgrade strength values (see

Appendix C). Table 2 below summarizes our segments.

Table 2 – Roadway Segments

Segment Roadway Extents Mile Posts

1 State Highway 13 to Sprague Gulch Road MP 0.0 to 12

2 Sprague Gulch Road to County Road 26 MP 12 to 23

3 County Road 26 to County Road 22 MP 23 to 34

4 County Road 22 to State Highway 64 MP 34 to 41

Rio Blanco County Road 5 Project No. 29-202

Subgrade Materials

Based on the results of our field exploration and laboratory testing, the pavement subgrade material generally consisted of existing gravel, sand, silt and clay fill and natural sand, gravel, silt, clay and bedrock. These soils classified as A-1, A-2, A-4 and A-6 in accordance with the American Association of State Highway and Transportation Officials (AASHTO) and as

GM, GP-GM, SM, SC, CL, ML and CL-ML in accordance with the Unified Soil Classification

System (USCS).

Four composite bulk samples were grouped from samples obtained in the test holes and were subjected to laboratory classification and Hveem (R-value) testing (ASTM 2844).

Laboratory testing indicated that two of the bulk samples classified as A-2-4 and as an SM. R-value results on these two bulk samples indicated values of 26 and 27 at an exudation pressure of 300 psi. The third bulk sample classified as an A-4 and SM with an R-value of 38. The fourth bulk sample classified as an A-6 and SC with an R-value of 9. For design purposes, we interpreted Segment 1 as A-4 and A-6 and used an R-value of 9. We interpreted Segments 2 and 3 as A-2 and A-4 and used an R-value of 26. We interpreted Segment 4 as A-6 and used an R-value of 9.

A composite sample of the granular (base or chip seal) material beneath the existing asphalt was also subjected to laboratory classification and R-value testing. The sample had 2 percent fines (passing No. 200 sieve) and classified as an A-1 and SP with an R-value of 75.

Traffic Loading

Based on current and projected weekly volumes for each segment, we calculated the

18-kip Equivalent Single Axle Loads (ESALs) using traffic type percentages from the report by

RPI Consulting (Appendix C). All calculated ESALs were rounded up to obtain design ESALs used for each segment. Table 3 shows the ESALs used for the design of County Road 5 segments. Complete calculations of the design ESALs for flexible pavements are shown in

Appendix C.

Rio Blanco County Road 5 Project No. 29-202

Table 3 - Design Life Equivalent 18-kip Single Axle Loads (ESALs)

Roadway Segment 20-Year Flexible ESALs

Segment 1 3,100,000

Segment 2 2,700,000

Segment 3 1,300,000

Segment 4 1,800,000

Determination of Resilient Modulus (MR) of Subgrade for Design

From measured R-values, the resilient modulus for each segment was calculated using the CDOT 2006 Pavement Design Manual (see Table 4). The R-value and calculated resilient modulus listed below were used to determine the design thicknesses for the various flexible pavement sections for County Road 5.

Table 4 - Resilient Modulus for Pavement Thickness Design

Roadway Segment R-value Resilient

Modulus (psi)

Segment 1 9 3,448

Segment 2 26 6,010

Segment 3 26 6,010

Segment 4 9 3,448

New Alignment Hot Mix Asphalt Pavement Designs

The first designs address each section and can be used for new alignments or if the existing roadway were to be completely reconstructed. Rehabilitation designs using pulverization will be presented after the reconstruct designs to address incorporating on-site materials into the new roadway.

For each segment, a pavement design for full depth, composite, composite with subbase, and composite with subbase and geogrid were calculated using the DARWin version

3.1 computer program following the 2010 CDOT Pavement Design Manual and Tensar “Spectra

Pave” software. The various sections utilized a combination of hot mix asphalt (HMA), aggregate base course (ABC, R-value > 77) and CDOT Class 3 subbase. The geogrid should

Rio Blanco County Road 5 Project No. 29-202 consist of Tensar BX1100 or BX1200 or equivalent, as recommended below. The parameters used for pavement design for each segment are presented in Tables 5 through 8. A Class 3 subbase must have a minimum R-value of 65 and/or a maximum of 20 percent passing the No.

200 sieve. Pavement section thicknesses are presented below in Tables 9 through 12.

Table 5 – Flexible Pavement Design Parameters (Segment 1)

Asphalt Pavement Design Parameters

Initial Serviceability 4.5 Reliability Level, % 90

Terminal Serviceability 2.5 Overall Standard Deviation 0.44

Construction Stage 1 Resilient Modulus, psi 3,448

20 Year Design ESALs 3,100,000 HMA Str. Layer Coefficient 0.44

ABC Str. Layer Coefficient 0.12 Subbase Str. Layer Coefficient 0.10

Table 6 – Flexible Pavement Design Parameters (Segment 2)

Initial Serviceability 4.5 Reliability Level, % 90

Terminal Serviceability 2.5 Overall Standard Deviation 0.44

Construction Stage 1 Resilient Modulus, psi 6,010

20 Year Design ESALs 2,700,000 HMA Str. Layer Coefficient 0.44

Table 7 – Flexible Pavement Design Parameters (Segment 3)

Initial Serviceability 4.5 Reliability Level, % 90

Terminal Serviceability 2.5 Overall Standard Deviation 0.44

Construction Stage 1 Resilient Modulus, psi 6,010

20 Year Design ESALs 1,300,000 HMA Str. Layer Coefficient 0.44

Rio Blanco County Road 5 Project No. 29-202

Table 8– Flexible Pavement Design Parameters (Segment 4)

Asphalt Pavement Design Parameters

Initial Serviceability 4.5 Reliability Level, % 90

Terminal Serviceability 2.5 Overall Standard Deviation 0.44

Construction Stage 1 Resilient Modulus, psi 3,448

20 Year Design ESALs 1,800,000 HMA Str. Layer Coefficient 0.44

The Darwin and Tensar “Spectra Pave” Program outputs for the recommended pavement thickness designs are provided in Appendix C and are summarized below.

Table 9 – Recommended Pavement Sections (Segment 1)

Segment Pavement Type Design Life

(years) Thickness (inches)

Treatment Cost (Yd2)

Segment

Full Depth HMA 20 12” HMA $44.60

HMA + ABC 20 6” HMA + 21” ABC $43.49

HMA + ABC +

Subbase

6” HMA + 6” ABC + 18”

Subbase $44.06

HMA + ABC +

Geogrid* + Subbase

6” HMA + 6” ABC +

BX1200 +

9” Subbase $39.50

*Tensar BX1200 Geogrid (minimum) or equivalent

Table 10 – Recommended Pavement Sections (Segment 2)

Design Life

(years) Thickness (inches)

Treatment Cost (Yd2)

Segment

Full Depth HMA 20 10” HMA $37.44

HMA + ABC 20 6” HMA + 14” ABC $36.70

HMA + ABC +

Subbase

6” HMA + 6” ABC + 9”

$36.50

6” HMA + 4” ABC +

BX1200 +

4” Subbase $33.36

*Tensar BX1200 Geogrid (minimum) or equivalent

Rio Blanco County Road 5 Project No. 29-202

Table 11 – Recommended Pavement Sections (Segment 3)

Segment Pavement Type Design Life

(years) Thickness (inches)

Treatment Cost (Yd2)

Segment

Full Depth HMA 20 9” HMA $33.86

HMA + ABC 20 6” HMA + 10” ABC $32.82

HMA + ABC +

Subbase

6” HMA + 6” ABC + 5”

$33.14

6” HMA + 4” ABC + BX

1100 +

4” Subbase $33.36

*Tensar BX1100 Geogrid (minimum) or equivalent

Table 12 – Recommended Pavement Sections (Segment 4)

Design Life

(years) Thickness (inches)

Treatment Cost (Yd2)

Segment

Full Depth HMA 20 11” HMA $41.02

HMA + ABC 20 6” HMA + 18” ABC $40.58

HMA + ABC +

Subbase

6” HMA + 6” ABC + 15”

$41.54

6” HMA + 6” ABC +

BX1200 +

6” Subbase $36.98

*Tensar BX1200 Geogrid (minimum) or equivalent Materials costs used in Tables 9-12 are listed in Appendix C.

Rehabilitation Hot Mix Asphalt Pavement Designs

Additional savings from reuse of on-site materials should also be considered because of the large amount of this roadway which will be rehabilitated and widened on the existing grade.

The rehabilitation designs also were proposed with consideration of safety and maintenance of traffic during construction. Savings through such treatments pulverization or overlay of existing are proposed depending on section.

Because of the differing conditions for traffic loading, subgrade soil strength and pavement thickness on the four segments of Rio Blanco County Road 5, four different rehabilitation treatments are proposed.

Segment 1 - In Segment 1, the pavement thickness varies from 7 to 17 inches. This variation is believed to be caused by roadway settlement which was periodically patched with thin overlays. For the rehabilitation, we recommend that the existing roadway width be pulverized to a depth two inches below the existing Hot Mix Asphalt (HMA). Based on our

Rio Blanco County Road 5 Project No. 29-202 borings the pulverization depth would average 12 to 14 inches. After pulverization, a new layer of 6 inches of ABC Class 6 and 6 inches of HMA should be placed.

Since the intent of the rehabilitation is also to widen the roadway to at least 40 feet, the widened section should consist of 18 inches of Pit run ABC Class 3, 6 inches of ABC Class 6, and 6 inches of HMA as described in Table 9.

Depending the future roadway alignment, this section may be made up of a saddle bag section with widening on each side of the existing roadway, or it may be widened to one side or the other of the existing roadway.

If the roadway is widened to one side or if a section is to be reconstructed on virgin alignment, the geogrid section described in Table 9 would also be acceptable. We recommend that both sections be shown in the plans as acceptable so that the contractor may choose the more cost effective section. If a new alignment section is required, pulverized old pavement and

ABC can be reused in place of pit run subbase.

Segment 2 - Segment 2 has been recently overlaid and contains a very thick HMA section in good condition. In this section, we recommend that the existing roadway be overlaid with 6 inches of HMA to address future loading. For the widening, we recommend that the composite section from Table 10 be used to bring the widening up to the proper elevation so that the 6 inches of new HMA is uniform across the entire roadway. The recommended section from Table 10 consists of 9 inches of ABC Class 3, 6 inches of ABC Class 6, and 6 inches of

HMA.

Again, for any new alignment sections in this segment, we recommend that the geogrid design listed in Table 10 also be allowed.

Segment 3 - For Segment 3 we recommend that the existing pavement be pulverized to a depth of 8 inches to be followed by application of 6 inches of ABC Class 6 and 6 inches of

HMA.

For the sections to be widened or new alignment sections we recommend that the

Section Listed in Table 11 consisting of 5 inches of pit run ABC Class 3, 6 inches of ABC

Class6, and 6 inches of HMA.

The geogrid design in Table 11 should also be allowed as an acceptable alternate for one sided widening or new alignment sections.

Segment 4 - In segment four, we recommend that the existing roadway be pulverized to a depth of 8 to 10 inches (2 inches below the existing HMA) followed by 6 inches of ABC Class

6 and 6 inches of HMA. For the widened sections we recommend the treatment listed in Table

Rio Blanco County Road 5 Project No. 29-202

12 consisting of 15 inches of pit run ABC Class 3, 6 inches of ABC Class 6, and 6 inches of

HMA.

Again the geogrid thickness design listed in Table 12 should also be allowed for one sided widened sections, and new alignments.

The pavement design calculations for all of the designs appear in Appendix D and using the materials costs listed in Appendix D, the estimated cost per square yard for the rehabilitation treatments appear in Table 13.

Table 13 – Recommended Rehabilitation Pavement Sections

Segment Rehabilitation

Treatment

Design Life

(years)

Treatment Cost** (Yd2)

Pulverize 14" +

ABC + HMA

20 $38.23

2 Overlay 6" HMA 20 $28.47

Pulverize 8" +

ABC + HMA

20 $32.09

Pulverize 10" +

ABC + HMA

20 $35.45

** Costs are based on Materials and are weighted assuming 24 foot of Rehabilitation Treatment and 16 feet of widening using ABC Class 3 and ABC Class 6 and HMA Materials costs used in Tables 9-13 are listed in Appendix C.

Hot Mix Asphalt Type

Because of the heavy loads and often slow moving (<45 mph) nature of anticipated traffic for this project, we recommend that the asphalt mix for this project meet the specifications for Grading SX (100) in accordance with the specifications. The number of SuperPave Gyratory revolutions (Ndes) for the asphalt mixes should be at 100 gyrations. We recommend that unmodified performance grade asphalt binder meeting the CDOT requirements for performance grade PG 58-28 be used in the lower layers and that the top lift contain Performance Graded

Asphalt PG 76-28. PG 58-28 is a 98% reliability binder for both binder rutting resistance and thermal cracking for the Meeker area based on data from the FHWA Binder Selection Program, LTPPBind. Based on recommendations from the same binder selection program, PG 76-28 is a

98% reliability binder for the top lift, and will give the new pavement additional resistance to rutting. The lower lifts should meet the requirements for SX (100) and be placed at thicknesses of two and three inches. The top 2-inch lift should conform to SX (100) with PG 76-28 binder.

Rio Blanco County Road 5 Project No. 29-202

Aggregates for hot mix asphalt should be of uniform quality, composed of clean, hard, durable particles of crushed stone, gravel, or slag. Excess of fine material should be wasted before crushing. The specifications of gradation for the Grading SX are shown below:

Table 13 – Gradation for Grading SX Grading SX

Sieve Size Passing by Weight, % 3 /4” 100 1 /2” 90-100 3 /8” * #4 * #8 28-58

#30 * #200 2-10

*See details in CDOT Standard Specifications.

Subgrade Preparation

Prior to placing aggregate base course and asphalt pavement, the entire subgrade area should be scarified to a depth of 12 inches and recompacted to the specified relative compaction with a moisture content in accordance with the CDOT Standard Specifications for

Road and Bridge Construction. In locations where the in-place subgrade contains more than 40 percent minus No. 200 sieve material, a separator fabric conforming to CDOT Separator

Geotextile Class B should be installed prior to placing the subbase. Based on our investigation, a separator fabric may be necessary in areas of test holes YA-1, YA-12, YA-21 and YA-30 through YA-32. Imported fill material should be compacted in thin lifts to within 2 percent of optimum moisture content in accordance AASHTO T 99 or T 180. As noted above, the ABC should have a minimum R-value of 77. For all layers, drainage needs to be addressed during construction to prevent ponding of water and provide for ease of construction. The pavement subgrade and each layer ABC should be proof rolled with a heavily loaded pneumatic-tire vehicle. Areas which deform more than 0.5 inch under heavy wheel loads should be removed, replaced if necessary and reworked to achieve a stable subgrade prior to paving. We recommend that proof rolling and compaction tests be performed under the direct supervision of a representative of the geotechnical engineer.

Drainage Considerations

The collection and diversion of surface drainage away from paved areas is critical to the satisfactory performance of the pavement. Proper drainage design should include prevention of

Rio Blanco County Road 5 Project No. 29-202 ponding of water on or immediately adjacent to pavement areas. Concentrated runoff should be avoided in areas susceptible to erosion. Slopes and other stripped areas should be protected against erosion by re-vegetation or other methods.

WATER SOLUBLE SULFATE

Based laboratory test results, we anticipate a Class 0 exposure for concrete due to the presence of water-soluble sulfate. Based on ACI 201.2R-01, “Guide to Durable Concrete,” concentrations between 0.0 and 0.1 percent represent Class 0 exposure (low). For cast-in-place structures such as foundations and pavements placed on onsite soils, ACI recommends any type of cement can be used for improvements at this site. Structural fill and aggregate base course are assumed to have Class 0 exposure or no effect on concrete.

LIMITATIONS

This study was conducted in accordance with generally accepted geotechnical engineering practices in this area for use by the client for design purposes. The conclusions and recommendations submitted in this report are based upon the data obtained from exploratory test holes, field reconnaissance and anticipated construction. The nature and extent of subsurface variations across the site may not become evident until excavation is performed.

If during construction, fill, soil, or water conditions appear to be different from those described herein, this office should be advised at once so reevaluation of the recommendations may be made. We recommend on-site observation of excavations and pavement subgrade by a representative of the geotechnical engineer.

The scope of services for this project did not include, specifically or by implication, any environmental or biological (e.g., mold, fungi, and bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions or biological conditions. If the owner is concerned about the potential for such contamination, conditions or pollution, other studies should be undertaken.

The report was prepared in substantial accordance with the generally accepted standards of practice for geotechnical engineering as exist in the site area at the time of our investigation. No warranties, express or implied, are intended or made. The recommendations in this report are based on the assumption that Yeh and Associates will conduct an adequate

Rio Blanco County Road 5 Project No. 29-202 program of construction testing and observation to evaluate compliance with our recommendations.

YEH AND ASSOCIATES, INC. Reviewed by:

Keith E. Asay Richard D. Johnson, P.E.

Staff Engineer Senior Geotechnical Engineer

Reviewed by:

Robert F. LaForce, P.E.

Senior Materials Manager

APPENDIX A

LOGS AND LEGEND OF EXPLORATORY BORINGS

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

IZ

E

-2

B

O R

IN

G

S .G

P J

R D

J.

G

D T

2/

4/

7/12

6/12

11/12

YA-01

Elevation: 7219.4 ft

6/12

7/12

6/12

YA-02

Elevation: 7192.8 ft

23/12

8/12

YA-03

Elevation: 6964.6 ft

17/12

13/12

8/12

EST ELEV

YA-04

Elevation: 6940.0 ft

23/12

8/12

6/12

YA-05

Elevation: 6849.2 ft

Figure A-1

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

B

O R

IN

G

S .G

P J

R D

J.

G

14/12

4/12

5/12

YA-06

Elevation: 6798.8 ft

18/12

4/12

4/12

7/12

14/12

YA-07

Elevation: 6727.0 ft

9/12

5/12

8/12

YA-08

Elevation: 6706.0 ft

8/12

14/12

7/12

YA-09

Elevation: 6640.9 ft

14/12

9/12

7/12

YA-10

Elevation: 6571.0 ft

Figure A-2

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

B

O R

IN

G

S .G

P J

R D

J.

G

36/12

11/12

9/12

YA-11

Elevation: 6523.1 ft

8/12

5/12

4/12

4/12

1/12

YA-12

Elevation: 6440.0 ft

27/12

7/12

7/12

YA-13

Elevation: 6425.7 ft

9/12

12/12

6/12

YA-14

Elevation: 6365.9 ft

16/12

4/12

9/12

YA-15

Elevation: 6308.2 ft

Figure A-3

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

B

O R

IN

G

S .G

P J

R D

J.

G

14/12

12/12

10/12

YA-16

Elevation: 6233.6 ft

30/12

18/12

11/12

YA-17

Elevation: 6206.9 ft

16/12

12/12

21/12

YA-18

Elevation: 6183.1 ft

20/12

7/12

11/12

YA-19

Elevation: 6133.2 ft

7/12

7/12

8/12

YA-20

Elevation: 6100.6 ft

Figure A-4

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

B

O R

IN

G

S .G

P J

R D

J.

G

9/12

7/12

4/12

YA-21

Elevation: 6092.2 ft

18/12

20/12

8/12

YA-22

Elevation: 6056.7 ft

16/12

30/5

30/3

YA-23

Elevation: 6015.0 ft

21/12

31/12

12/12

YA-24

Elevation: 5992.3 ft

23/12

11/12

9/12

YA-25

Elevation: 5964.7 ft

Figure A-5

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

B

O R

IN

G

S .G

P J

R D

J.

G

20/12

15/12

9/12

YA-26

Elevation: 5908.9 ft

50/12

16/12

6/12

YA-27

Elevation: 5903.1 ft

50/11

14/12

11/12

YA-28

Elevation: 5868.1 ft

26/12

11/12

9/12

YA-29

Elevation: 5825.2 ft

12/12

13/12

11/12

YA-30

Elevation: 5842.4 ft

Figure A-6

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

B

O R

IN

G

S .G

P J

R D

J.

G

25/12

29/10

9/12

40/12

55/9

50/4

50/3

YA-31

Elevation: 5737.1 ft

27/12

41/12

50/8

YA-32

Elevation: 5738.6 ft

Figure A-7

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

B

O R

IN

G

S .G

P J

R D

J.

G

7/12

16/12

6/12

6/12

YA-33

Elevation: 6726.2 ft

23/12

7/12

17/12

4/12

YA-34

Elevation: 6726.3 ft

Figure A-8

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

B

O R

IN

G

S .G

P J

R D

J.

G

11/12

8/12

6/12

2/12

YA-35

Elevation: 6441.9 ft

25/12

13/12

5/12

4/12

3/12

YA-36

Elevation: 6442.1 ft

Figure A-9

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

B

O R

IN

G

S .G

P J

R D

J.

G

23/12

25/12

6/12

5/12

7/12

YA-37

Elevation: 5990.9 ft

8/12

6/12

4/12

YA-38

Elevation: 5991.1 ft

Figure A-10

GEOTECHNICAL ENGINEERING CONSULTANTS

D ep th ft

YEH AND ASSOCIATES, INC. Rio Blanco County Road 5

Project Number: 29-202

F E

N C

E S

B Y

D E

P T

H

A S

B

O R

IN

G

S .G

P J

R D

J.

G

26/12

30/12

19/12

7/12

5/12

YA-39

Elevation: 5745.7 ft

26/12

13/12

6/12

4/12

YA-40

Elevation: 5745.9 ft

Figure A-11

APPENDIX B

LABORATORY TEST RESULTS

Applied Normal Pressure, ksf

1 4

2 4

Job No:

18.6 RDJ

0.1

Graph Number

Boring Number Depth, ft

Checked By:

FILL: SAND, clayey

TH-2 96 0.0 CLAY, sandy

TH-1

29-202 Project Name:

Consolidation(-) /Swell(+), % Soil Description

Rio Blanco County Road 5 Figure No. B-1

YEH & ASSOCIATES, INC

Natural Dry Density, pcf

Moisture Content, 17.5

SWELL /

CONSOLIDATION

GRAPH

SWDrawn By:

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

0.1 1 10 100

C on so lid at io n(

Sw el l(+

WATER ADDED

Graph 2

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

0.1 1 10 100

C on so lid at io n(

Sw el l(+

WATER ADDED

Graph 1

1 4

2 4

Job No:

SWDrawn By:

Consolidation(-) /Swell(+), % Soil Description

YEH & ASSOCIATES, INC

Natural Dry Density, pcf

Moisture Content, 24.4

SWELL /

CONSOLIDATION

GRAPH

RDJ

Rio Blanco County Road 5 Figure No. B-2

0.2

-0.1

Checked By:

SAND, silty

SILT, sandy11.9

29-202 Project Name:

Graph Number

Boring Number Depth, ft

YA-12 88

YA-5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

0.1 1 10 100

C on so lid at io n(

Sw el l(+

WATER ADDED

Graph 2

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

0.1 1 10 100

C on so lid at io n(

Sw el l(+

1 4

2 4

Job No:

15.1 RDJ

-0.4

Graph Number

Boring Number Depth, ft

Checked By:

SILT, sandy

YA-29 98 0.8 SAND, clayey

YA-21

29-202 Project Name:

Consolidation(-) /Swell(+), % Soil Description

Rio Blanco County Road 5 Figure No. B-3

YEH & ASSOCIATES, INC

Natural Dry Density, pcf

Moisture Content, 16.3

SWELL /

CONSOLIDATION

GRAPH

SWDrawn By:

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

0.1 1 10 100

C on so lid at io n(

Sw el l(+

WATER ADDED

Graph 2

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

0.1 1 10 100

C on so lid at io n(

Sw el l(+

1 4

Job No:

SWDrawn By:

Consolidation(-) /Swell(+), % Soil Description

YEH & ASSOCIATES, INC

Natural Dry Density, pcf

Moisture Content, 16.6

SWELL /

CONSOLIDATION

GRAPH

RDJ

Rio Blanco County Road 5 Figure No. B-4

-0.3

Checked By:

CLAY (CL)

29-202 Project Name:

Graph Number

Boring Number Depth, ft

YA-30

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

0.1 1 10 100

C on so lid at io n(

Sw el l(+

Graph 2

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

0.1 1 10 100

C on so lid at io n(

Sw el l(+

1 ½"

1"

¾ "

½"

Sieve Size

Passing

3"

2 ½"

2" ce n t P as si n g

20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches U.S. Standard Sieves Size of Particles in mm

1002"

Drawn By: SAW

Date: 12/14/09

#200

Project No.: 29-202

Figure No.: B-5

LL

PL

Gravel (%)

Sand (%)

#10

#40

Fines (%) 47 PI 16

⅜"

#4

Rio Blanco County Road 5 Project Name: Yeh & Associates, Inc.

Geotechnical Engineering Consultants

SIEVE ANALYSIS

Sample ID: YA-1

Sample Depth (ft.):

Sample Description: FILL: Clayey SAND (SC) Checked By: RDJ

0.010.1110100

P er

Particle Size (mm)

Revised 04/227/2004

Sieve Size

Passing

3"

2 ½"

2"

1 ½"

1"

¾ "

½" ce n t P as si n g

20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches U.S. Standard Sieves Size of Particles in mm

1002"

Drawn By: SAW

Date: 12/14/09 Checked By: RDJ Sample

Description: FILL: Clayey SAND (SC)

Fines (%) 26 PI 11

Rio Blanco County Road 5 Project Name:

Sample ID: YA-2

Sample Depth (ft.):

⅜"

#4

#10

#40

Gravel (%)

Sand (%)

LL

PL

#200

Project No.: 29-202

Figure No.: B-6

Yeh & Associates, Inc.

Geotechnical Engineering Consultants

SIEVE ANALYSIS

0.010.1110100

P er

1 ½"

1"

¾ "

½"

Sieve Size

Passing

3"

2 ½"

2" ce n t P as si n g

20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches U.S. Standard Sieves Size of Particles in mm

1002"

Drawn By: SAW

Date: 12/14/09

#200

Project No.: 29-202

Figure No.: B-7

LL

PL

NL

NP

Gravel (%)

Sand (%)

#10

#40

Fines (%) 7 PI NP

⅜"

#4

Rio Blanco County Road 5 Project Name: Yeh & Associates, Inc.

Geotechnical Engineering Consultants

SIEVE ANALYSIS

Sample ID: YA-4

Sample Depth (ft.):

Sample Description: Weathered SANDSTONE Checked By: RDJ

0.010.1110100

P er

Passing

3"

2 ½"

2"

1 ½"

1"

¾ "

½" ce n t P as si n g

20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches U.S. Standard Sieves Size of Particles in mm

1002"

Drawn By: SAW

Date: 12/14/09 Checked By: RDJ Sample

Description: FILL: Gravelly, silty SAND (SM)

Fines (%) 15 PI NP

Rio Blanco County Road 5 Project Name:

Sample ID: YA-4

Sample Depth (ft.):

⅜"

#4

#10

#40

NL

NP

Gravel (%)

Sand (%)

LL

PL

#200

Project No.: 29-202

Figure No.: B-8

Yeh & Associates, Inc.

Geotechnical Engineering Consultants

SIEVE ANALYSIS

0.010.1110100

P er

1 ½"

1"

¾ "

½"

Sieve Size

Passing

3"

2 ½"

2" ce n t P as si n g

20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches U.S. Standard Sieves Size of Particles in mm

1002"

Drawn By: SAW

Date: 12/14/09

#200

Project No.: 29-202

Figure No.: B-9

LL

PL

NL

NP

Gravel (%)

Sand (%)

#10

#40

Fines (%) 20 PI NP

⅜"

#4

Rio Blanco County Road 5 Project Name: Yeh & Associates, Inc.

Geotechnical Engineering Consultants

SIEVE ANALYSIS

Sample ID: YA-5

Sample Depth (ft.):

Sample Description: Silty SAND (SM) Checked By: RDJ

0.010.1110100

P er

Passing

3"

2 ½"

2"

1 ½"

1"

¾ "

½" ce n t P as si n g

20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches U.S. Standard Sieves Size of Particles in mm

1002"

Drawn By: SAW

Date: 12/14/09 Checked By: RDJ Sample

Description: Silty SAND (SM)

Fines (%) 18 PI NP

Rio Blanco County Road 5 Project Name:

Sample ID: YA-6

Sample Depth (ft.):

⅜"

#4

#10

#40

NL

NP

Gravel (%)

Sand (%)

LL

PL

#200

Project No.: 29-202

Figure No.: B-10

Yeh & Associates, Inc.

Geotechnical Engineering Consultants

SIEVE ANALYSIS

0.010.1110100

P er

1 ½"

1"

¾ "

½"

Sieve Size

Passing

3"

2 ½"

2" ce n t P as si n g

20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches U.S. Standard Sieves Size of Particles in mm

1002"

Drawn By: SAW

Date: 12/14/09

#200

Project No.: 29-202

Figure No.: B-11

LL

PL

NL

NP

Gravel (%)

Sand (%)

#10

#40

Fines (%) 18 PI NP

⅜"

#4

Rio Blanco County Road 5 Project Name: Yeh & Associates, Inc.

Geotechnical Engineering Consultants

SIEVE ANALYSIS

Sample ID: YA-7

Sample Depth (ft.):

Sample Description: Silty SAND (SM) Checked By: RDJ

0.010.1110100

P er

Passing

3"

2 ½"

2"

1 ½"

1"

¾ "

½" ce n t P as si n g

20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches U.S. Standard Sieves Size of Particles in mm

1002"

Drawn By: SAW

Date: 12/14/09 Checked By: RDJ Sample

Description: Gravelly, silty SAND (SM)

Fines (%) 21 PI NP

Rio Blanco County Road 5 Project Name:

Sample ID: YA-8

Sample Depth (ft.):

2 to 6

⅜"

#4

#10

#40

NL

NP

Gravel (%)

Sand (%)

LL

PL

#200

Project No.: 29-202

Figure No.: B-12

Yeh & Associates, Inc.

Geotechnical Engineering Consultants

SIEVE ANALYSIS

0.010.1110100

P er

1 ½"

1"

¾ "

½"

Sieve Size

Passing

3"

2 ½"

2" ce n t P as si n g

20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches U.S. Standard Sieves Size of Particles in mm

1002"

Drawn By: SAW

Date: 12/14/09

#200

Project No.: 29-202

Figure No.: B-13

LL

PL

NL

NP

Gravel (%)

Sand (%)

#10

#40

Fines (%) 17 PI NP

⅜"

#4

Rio Blanco County Road 5 Project Name: Yeh & Associates, Inc.

Geotechnical Engineering Consultants

SIEVE ANALYSIS

Sample ID: YA-9

Sample Depth (ft.):

Sample Description: Silty SAND (SM)…