mt-a2015013_PavementReport.pdf

PAVEMENT REPORT

MT PHILLIPS 364(1)

Short Oil Road

IDIQ Contract No. DTFH70-15-D-00007 Task Order No. 69056719F000008

Project 18-3762G R3

Submitted by

2511 Holman Avenue P. O. Box 80190

Billings, Montana 59108-0910

Prepared for

Robert Peccia & Associates P. O. Box 5653

Helena, Montana 59604-5653

August 12, 2019

Table of Contents

Description Page

A. Introduction

A.1. Project Description A.2. Scope of Services and Background

B. Results B.1. General Site Topography B.2. Geology B.3. Pavement Conditions B.4. Boring Results

C. Laboratory Testing Program/Procedures C.1. General C.2. General C.3. Subgrade Samples C.4. Base and Subbase Samples C.5. Corrosion Test Results

D. Analysis/Recommendations D.1. Drainage D.2. Cut and Fill Slopes D.3. Pavement Analysis D.4. Unstable Areas and Digouts D.5. Existing Gravel Surfacing D.6. Specifications

E. Procedures E.1. Drilling and Sampling E.2. Soil Classifications E.3. Groundwater Observations

F. General Recommendations F.1. Basis of Recommendations F.2. Review of Design F.3. Groundwater Fluctuations F.4. Use of Report F.5. Level of Care

Appendix

Partial Topographic Sketch Geologic Map Boring Location Sketch Boring Photos (3 sheets) Fill Slope Photos (1 sheet) Descriptive Terminology – Soil Log of Boring Sheets ST-1 through ST-12

Laboratory Test Results (16 sheets) Summary of Corrosion Test Results

A. Introduction

A.1. Project Description As can been seen on the attached Boring Location Sketch, Short Oil Road begins on the south side of

Malta then heads south for 4 miles and ends near the intersection with Regina Road at the end of the existing pavement. Short Oil Road is also known as Highway 364. This section serves to allow outdoor recreationalists access to Fourchette Bay on Fort Peck Lake and surrounding Charles M. Russell National

Wildlife Refuge. The road is also used by Montana Fish, Wildlife, and Parks staff, as well as for fire suppression on Federal and State lands.

The project was initially planned to be an asphalt overlay with limited digout areas. SK Geotechnical performed a pavement reconnaissance along the project and the results are presented in a report dated

December 12, 2018. It was our opinion the existing pavement was in very poor condition across the entire length of the project due to widespread checkerboard cracking, pavement failures (alligator cracking), and rutting. Numerous patches were also present along the 70-year old asphalt pavement surface. Based on these observations, it was decided rehabilitation with reconstruction should be used for the entire length of the project. Full depth recycling (FDR) was considered the best approach for the project, and several preliminary alternatives were presented in the Pavement Reconnaissance Report.

A.2. Scope of Services and Background To evaluate the feasibility of FDR rehabilitation for the project, SK Geotechnical performed a pavement evaluation along the 4-mile alignment. Our scope of services is briefly described below.

Follow-up reconnaissance by a geotechnical engineer.

Painting the proposed boring locations and setting offset stakes. During the staking, the latitude and longitude coordinates were determined by a hand-held Garmin GPS. These coordinates are indicated on the attached Log of Boring sheets and shown on the attached Boring Location

Sketch. Reference points related to mileage beginning at the south end were also used for boring locations.

Coordinating the location of underground utilities near the boring locations.

Conducting a total of 12 penetration test borings to a depth of 5 feet along the project. As the borings were performed, our geotechnical engineer closely observed the existing base and subbase courses and recorded the pavement section to the nearest 1/4 inch.

Collecting bag samples of the existing base, subbase, and subgrade for various laboratory tests.

Classifying the samples and preparing boring logs by a geotechnical engineer.

Robert Peccia & Associates August 12, 2019 Project 18-3762G R3 Page 2

Selecting four subgrade samples for classification, Proctor, and California bearing ratio (CBR) tests. Creating two composite samples of existing base course and two composite samples of existing subbase course for classification tests.

Discussing the project with Mr. Brad Thompson of Robert Peccia & Associates (RPA).

Preparing this Pavement Report containing logs of the borings, our analysis of the field and laboratory tests, and recommendations for pavement rehabilitation.

B. Results

B.1. General Site Topography As can been seen on the Partial Topographic Sketch, the north end of the project is at the intersection of

Short Oil Road and Highway 191, located at the southern edge of the City of Malta. Short Oil Road, also known as Old US Highway 364, then extends to the southeast 4 miles until just before the intersection with Regina Road (heading west) and South Black Coulee Road (heading east).

During the reconnaissance, it was readily apparent that when the road was originally constructed, it was intentionally built up above adjacent grades. Almost every boring performed for the project encountered existing embankment fill associated with this built up roadway. The alignment does cross through gently rolling terrain, and there are fills ranging from 5 to 20 feet high. These fills have relatively steep sideslopes and appeared to be at about 1V:2H (vertical:horizontal) in the top portion and then steepened to about 1V:1H. This resulted in many of the larger embankment fills having a barn roof shape.

Photographs of each of the borings as well as some of the fills are included with this report. Numerous other photographs are available upon request.

B.2. Geology A portion of the Geologic Map of the Malta 30' x 60' Quadrangle, Northeast Montana, Robert N.

Bergantino, 1999, is attached. The map indicates the Short Oil Road alignment is situated in Laurentide

Glacial Deposits underlain by the Claggett Shale Formation.

B.3. Pavement Conditions The condition of the existing pavement is very well documented in our Pavement Reconnaissance Report prepared for the project, dated December 12, 2018. Refer to this report for specific information related to pavement conditions and distress. In summary, the existing pavement is 70 years old and showing severe deterioration in the form of checkerboard cracking, alligator cracking, edge cracking, rutting, and stripping for almost the entire project. Based on these observations, the Pavement Reconnaissance Report

Project 18-3762G R3 Page 3 indicates the pavement is just too old and brittle to receive an overlay (preservation) and rehabilitation was recommended

B.4. Boring Results

B.4.a. Logs. Log of Boring sheets indicating the depth and identification of the various soil strata, the penetration resistances, laboratory test data, and water level information are attached. It should be noted, the depths shown as boundaries between the strata are only approximate. The actual changes may be transitions and the depths of the changes vary between borings.

B.4.b. Summary Table. Table 1 following this page summarizes the existing pavement and subgrade conditions at Borings ST-1 through ST-12 along the project. The existing pavement thicknesses and subgrade conditions are discussed in more detail below.

B.4.c. Existing Pavement. Using all of the borings except Borings ST-1 (gravel surfacing) and ST-8

(patched area), the average existing pavement section is indicated below.

Existing 70-year-old Pavement 2½"

Existing 3/4-inch Base Course 2¼"

Existing 4-inch minus Subbase Course 4½"

Total Thickness 9¼"

B.4.d. Subgrade. The attached boring logs outline more details about the soil stratum encountered by each boring. The primary subgrade encountered by the borings was sandy lean clay with some areas of clayey sand. As previously indicated, the majority of the clayey soils were fill used to create an embankment for the roadway. Penetration resistances in the sandy lean clay indicated it generally was very stiff to soft but primarily stiff to firm. Penetration resistances in the clayey sand indicated it was very loose to medium dense but primarily loose.

B.4.e. Groundwater Observations. Groundwater was not encountered in the borings to their termination depth of about 5 feet while drilling. Based on our observations of the alignment and boring results, we do not anticipate groundwater will be encountered. Even so, surface water runoff still must be considered, especially when considering the moisture sensitivity of the lean clays. If these clay soils get wet during construction, they will become very soft to soft causing materials to pump and rut.

Project 18-3762G R3 Page 4

Table 1. Existing Pavement and Anticipated Subgrade Conditions Boring ST-2 ST-3 ST-4 ST-5 ST-6 ST-7 ST-8(2) ST-9 ST-10 ST-11 ST-12 Average

Date Drilled 5/10/19 5/10/19 5/10/19 5/10/19 5/9/19 5/9/19 5/9/19 5/9/19 5/9/19 5/9/19 5/9/19

Reference Point 0.05 0.5 1.0 1.5 2.0 2.5 3 3.1 3.4 3.7 3.95

Existing PMS 3" 2½" 2½" 3" 3" 3" 3" 2" 1¾" 2¾" 2¾" 2½"

Existing Base 2" 2" 3½" 2½" 2" 1½" 2½" 3½" 2¾" 2½" 1¾" 2¼"

Existing Subbase 3¾" 4¼" 4½" 4¼" 4½" 4½" -- 4" 4"" 6" 5¾" 4½"

Total Thickness 8¾" 8¾" 10½" 9¾" 9½" 9" 5½" 9½" 8½" 11" 10¼" 9¼"

Subgrade(1)

Description Sandy

Lean Clay

Sandy Lean Clay over Silty

Sand

Sandy Lean Clay

Clayey Sand

Clayey Sand

Clayey Sand

Newer Poorly Graded

Sand Fill

Sandy Lean Clay

Sandy Lean Clay

Sandy Lean Clay

Sandy Lean Clay

ASTM Class CL CL to SM CL SC SC SC SP CL CL CL CL

N-Values 8, 10 12, 4 6, 11 6, 7 12, 12 7, 5 17 8, 7 5, 7 9, 5 9, 6

Consistency Stiff to firm Stiff to very loose Firm to very stiff Loose

Medium dense

Loose Medium dense Stiff to firm Firm to stiff Stiff to firm Stiff to firm

Moisture Content, % 2.1, 15.3 3.8, 9.5 13.3, 17.7 17.2, 16.0 12.8 14.2 4.5 12.8, 14.9 13.7, 14.2 8.7, 9.3 10.3

Optimum Moisture Content, %

12.3 12 12 11.5 10 9.6 6 12 11.9 12 12

Moisture Condition Wet Moist Wet Wet Wet Wet Moist Wet Wet Moist Moist

Risk of Subgrade Failure During Total Reconstruction

Medium Medium Medium High Medium High Low Medium High Low Low

(1) Anticipated subgrade that will be present beneath the proposed pavement section.

(2) Performed in recently patched pavement area, not included in average.

Project 18-3762G R3 Page 5

C. Laboratory Testing Program/Procedures

C.1. General After completion of the pavement borings, the samples were returned to our material testing laboratory.

Laboratory tests were performed in accordance with American Association of State Highway and

Transportation Officials (AASHTO) standards. All of the split-spoon samples from the borings were selected for moisture content tests, and the results are indicated on the attached Log of Boring Sheets. For subgrade samples, four samples were selected for classification (sieve analysis and Atterberg limits), Proctor, and CBR tests. To evaluate the quality of the existing base and subbase course, samples from almost all the borings were collected and composite samples were created. Two base composite samples and two subbase composite samples were selected for sieve analysis and Atterberg limit tests, and these results are attached. The test methods are outlined in Table 2 below.

Table 2. Test Methods

Test Name AASHTO Standard

Plasticity Index (Atterberg Limits) T89/T90

California Bearing Ratio, 300 psi Exudation T193

Sieve Analysis T11/T27

Natural Moisture Content T265

Moisture-Density, Standard Proctor T99

Corrosion Tests MDT Procedures

C.2. General

C.2.a. Moisture Content. Moisture content tests were performed on all of the split-spoon samples from the borings, and the results are indicated on the attached Log of Boring Sheets. These moisture content tests are also briefly summarized in the previous Table 1. In general, moisture contents in the clayey subgrade typically range from about 10 to 18 percent, and comparing these moisture contents to the optimum moisture contents generally indicated the clays were primarily wet, i.e., slightly over optimum.

C.3. Subgrade Samples Table 3 below summarizes the results of the laboratory tests performed on the four subgrade samples.

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Table 3. Summary of Subgrade Laboratory Tests

Boring Depth

Atterberg Limits

P200

ASTM Proctor

LL PL PI Class MDD OMC CBR

ST-2 1' to 4' 28 14 14 54 CL 120.0 psf 12.3% 4.2

ST-5 1' to 4' 26 11 15 47 SC 120.8 psf 11.5% 4.8

ST-7 1' to 4' 24 10 14 39 SC 128.9 psf 9.6% 4.0

ST-10 1' to 4' 34 10 24 55 CL 119.4 psf 11.9% 1.8

As can be seen above, the samples tested classified as sandy lean clay (CL) and clayey sand (SC).

Optimum moisture content of these materials ranges from 9.6 percent to 12.3 percent.

C.4. Base and Subbase Samples The results of the sieve analysis and Atterberg limits tests performed on the composite base and subbase samples are attached. The base samples classify as poorly graded sand with silt and gravel and poorly graded gravel with silt and sand. The AASHTO classification for these soils is A-1-a and the American

Society for Testing and Materials (ASTM) classification is SP-SM and GP-GM, respectively. These samples had 5.9 and 8.7 percent fines (material passing the Number 200 sieve) and appeared to be of very high quality, i.e., they were not contaminated with asphalt cement or subgrade. Similarly, the subbase samples classified as 3-inch minus well-graded gravel with silt and sand and poorly graded gravel with sand, AASHTO classification A-1-a. The ASTM classifications were GW-GM and GP. Again, the existing subbase appeared to be of good quality with almost no subgrade contamination at the bottom of the layer, although we visually observed some gravels as large as 4 inches when drilling.

C.5. Corrosion Test Results Corrosion tests were performed on the four subgrade samples and the results are attached.

D. Analysis/Recommendations

D.1. Drainage As previously indicated, Short Oil Road appears to have been well constructed by providing an embankment throughout almost the entire alignment. This embankment has been built up about 2 to 3 feet higher than adjacent grades creating a distinct ditch to help control surface water runoff and efficiently direct water off the pavement surface. In our opinion, the positive drainage created by the embankment has protected the existing base and subbase courses along the roadway, helping to prevent contamination from the clay subgrade. Flatter grades with poor surface water drainage, however, are present at intersections with existing roadways or approaches. This is particularly true at the

Project 18-3762G Page 7 northern-most intersection with Highway 191. Other intersections with poor drainage are at the approach road into the Malta landfill at RP 1.9 and the Y-intersection with Ready Mix Road at RP 3.2.

D.2. Cut and Fill Slopes It is our understanding this is a surfacing only project, and no cut or fill slopes are anticipated for the proposed Short Oil Road improvements. We did observe numerous fill slopes along the alignment. Fill slopes generally greater than about 8 feet had a barn roof shape, which is a safety related issue. We did not observe slope instability issues along these fill slopes most likely due to the positive drainage and dense vegetation growing along them. Some minor cut slopes are present along the project, and they also appeared stable.

D.3. Pavement Analysis

D.3.a. Traffic Analysis. Traffic data for the project was not provided for our pavement analysis. During our fieldwork, we observed the traffic along the roadway is relatively light, and mostly consist of locals accessing Malta from their ranches. Some recreational vehicles and boat traffic were observed as well as cattle trucks. Although, still light, more traffic was observed between Malta and the Malta Landfill associated with solid waste hauling.

Based on our preliminary observations, we estimate the daily equivalent single axle loads (ESALs) for the project would likely be less than 5. The Project Development and Design Manual (PDDM) indicates that if calculated ESAL values are less than 50,000 ESALs, then a minimum of 50,000 ESALs is to be used for the design of pavement. Therefore, 50,000 ESALs were used for our pavement design, which, in our opinion, is conservative. This value equates to daily ESALs of 6.85.

D.3.b. Methodology. Pavement sections were analyzed using a spreadsheet developed from the

AASHTO 1993 Pavement Design Manual. This spreadsheet is included later in this report and shows the various input parameters, structural coefficients, and resulting structural numbers (SN). These results are also summarized in more detail below.

The following design input parameters were used to evaluate pavement sections.

18-kip ESALs over initial performance: 50,000

Initial Serviceability: 4.2

Terminal Serviceability: 2.0

Reliability Level: 75%

Standard Deviation: 0.45

Roadbed Resilient Modulus: 5,550 psi

Project 18-3762G Page 8

As indicated above, we used a roadbed resilient modulus of 5,550 psi (pounds per square inch) for our analysis. This value was derived from the CBR values which ranged from 1.8 to 4.8, with an average value of 3.7. Using equations from the 1993 Pavement Design Manual, we converted this average CBR value to roadbed resilient modulus.

Based on these input parameters, we calculated a required SN of 2.14 will be needed to support a 20-year pavement design for the project. Based on our experience, the following three approaches were used to evaluate pavement sections:

Total reconstruction with new materials, Partial reconstruction after removing the existing old pavement surface, and

Partial depth recycling.

For each type, several alternative (typical) sections were evaluated and the results are indicated on the summary spreadsheet at the end of Section E. Each type is also discussed in more detail below along with the best alternative, in our opinion.

D.3.c. Total Reconstruction. Total reconstruction, Typicals 1 and 2, are pavement sections with all new materials; hot mix asphalt (HMA) pavement, and new crushed base course (CBC). These new materials are placed on subgrade that has been scarified, moisture conditioned, and recompacted to FP-14 Standard

Specifications. We anticipate these pavement sections will only be used for the extreme south end of the project near the Regina Road intersection where existing gravel surfacing may be replaced with the following total reconstruction pavement section.

Recommended Section for Total Reconstruction (Typical 2)

Hot Mix Asphalt Pavement 3"

Crushed Base Course, Grade D 6½"

Total Thickness 9½"

We realize that 2 1/2 inches of new pavement could be used as indicated in the Typical 1 section. We recommend using 3 inches of new pavement, however, to match the partial reconstruction section addressed below.

D.3.d. Partial Reconstruction. Partial reconstruction is an approach that can be considered to take advantage of the existing good quality base and subbase courses. The deteriorating existing pavement can be removed, then replaced with a thin layer of new CBC followed by new HMA pavement for the roadway. Typical Sections 4 and 5 address partial reconstruction, and we recommend using Typical 5 as summarized below.

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Recommended Section for Partial Reconstruction (Typical 5)

Hot Mix Asphalt Pavement 3"

New Crushed Base Course, Grade D 2"

Existing Base Course 2¼"

Existing Subbase Course 4½"

Total Thickness 11¾"

We anticipate this approach will raise grade by about 2 1/2 inches. Sequencing of this partial reconstruction will therefore be necessary. First, the existing 70-year old asphalt pavement having an average thickness of 2 1/2 inches needs to be removed. The method of removal, in our opinion, should be determined by the contractor based on their experience and equipment. Milling to salvage the old asphalt pavement materials may be feasible, which can then be combined with new base course to create recycled base course. When considering the significant pavement cracking, however, robust milling and grinding could break the pavement apart in pieces rather than small, blendable particles.

After removal of the existing old pavement, Road Reconditioning (Section 303) will be performed along the shoulders, existing base and subbase. If possible, extreme care should be taken during this work to limit the heavy rubber-tired construction traffic on the existing materials. This traffic promotes weakening of soft, wet clay subgrades by decreasing the clay's shear strength. For example, an identified very high risk subgrade (discussed later in report) that is 0.10-mile long could become 0.20 miles long due to the construction traffic.

D.3.e. Partial Depth Recycling (PDR) Pavement Sections. As the title to this subsection suggests, we are recommending "partial" depth recycling instead of "full" depth recycling. It has been our experience that full-depth reclaimers are not able to adequately grind up 4-inch rounded subbase courses as encountered by the borings. Instead the reclaimer teeth are broken off by the coarse gravels during the pulverization process, halting production. It is therefore our opinion FDR is not appropriate for the road due to the existing subbase.

Typicals 6 through 8 utilizing PDR are evaluated in the spreadsheet. For these approaches, we recommend adding 2 inches of CBC directly on top of the existing old asphalt pavement, then pulverizing to 5 to 6 inches depending on the typical selected. These pulverizing depths were selected to attempt to stay 1 inch above the coarse subbase and avoid damage to the contractor's equipment. We recommend

Typical 6 as summarized below for this approach.

Project 18-3762G Page 10

Recommended Section for PDR (Typical 6)

Hot Mix Asphalt Pavement 2½"

Recycled Base Course* 6"

Existing Subbase Course 4½"

Total Thickness 13"

* Recycled base course created by adding 2 inches of CBC on top of existing pavement and pulverizing to 5 inches.

We anticipate the above approach will raise grades about 4 1/2 inches.

D.3.f. Recommended Typical Pavement Section. Based on our observations and analysis, it is our opinion that Partial Reconstruction Typical 5 is best choice for the roadway. This section takes advantage of the existing good quality base and subbase courses, not only reducing construction costs but also providing an aggregate platform for construction equipment, i.e., construction equipment is not driving directly on the subgrade. If milling the 70-year old asphalt pavement is feasible, then the millings can also be blended with new CBC and reused as recycled base course.

D.4. Unstable Areas and Digouts

D.4.a. General. The risk of encountering unstable subgrades was evaluated at each of the borings in

Table 1, and the results are summarized below:

3 of 11 borings encountered subgrades having a low risk

5 of 11 borings encountered subgrades having a medium risk

3 of 11 borings encountered subgrades having a high risk

The risk of encountering/creating unstable subgrades is also directly associated with the construction schedule, methods, and repetitive loads due to heavy rubber-tired construction equipment. Also, more unstable conditions will be encountered in the spring after spring thaw and due to rainstorms. Late summer and early fall are normally much drier and hotter, and fewer unstable conditions will likely occur.

D.4.b. Identification of Unstable Areas. Assuming partial reconstruction is used, then construction equipment will be working on top of existing base and subbase. Once the base course is near or at final grade, we recommend proof rolling with a loaded tandem-wheel dump truck or water truck. If the material deflects 1/4-inch or more, then the underlying subgrade is unstable, and a subexcavation and placement of a stabilized pavement section is recommended. The actual extent will need to be determined by the project manager during construction even though we have anticipated extents indicated below.

Project 18-3762G Page 11

Consideration can be given to discussing the solution with the contractor as well as leaving the area(s) alone for several days. If given favorable weather and not subjected to construction equipment, some clays can become stable, i.e., clays become stronger as pore pressures dissipate.

D.4.c. Stabilized Pavement Section. Where unstable subgrades are identified, the extent should be subexcavated and provide either of the following stabilized pavement sections.

Option 1 Option 2 Hot Mix Asphalt Pavement 3" 3" New Crushed Base Course, Grade D 18" 4" Select Borrow --- 14" Stabilization Geogrid Yes Yes Nonwoven Separation Fabric Yes Yes

Total Thickness 21" 21"

Option 1 is preferred due to the better quality aggregate and its ability to bridge over soft subgrades.

Stabilization geogrid should meet the requirements of Table 714-4 and nonwoven separation fabric should meet the requirements of Table 714-1, Class 1, Type C of FP-14.

D.4.d. Extents. Based on the borings and our observations, we anticipate the following extents have a high risk or very high risk of being unstable during construction and will require subexcavation and placement of the selected stabilized pavement section.

Anticipated Extents for Unstable Subgrades

Extent Description Length and Anticipated Risk

High Risk (miles)

Very High Risk (miles)

RP 0.20 – 0.27 Swale, cracking, patches 0.07

RP 0.57 – 0.62 Cracking 0.05

RP 0.87 – 1.00 Swale, cracking, patches 0.13

RP 1.19 – 1.24 Cut slope, patches, cracking 0.05

RP 1.40 – 1.53 Swale, cracking 0.13

RP 1.75 – 1.90 Landfill Access Road Approach 0.15

RP 2.05 – 2.11 Cut slope, cracking 0.06

RP 2.32 – 2.40 Cut slope, patches, cracking 0.08

RP 2.60 – 2.65 Cracking, patches 0.05

RP 2.80 – 2.85 Cut slope, cracking 0.05

Project 18-3762G Page 12

Extent Description Length and Anticipated Risk

High Risk (miles)

Very High Risk (miles)

RP 2.90 – 3.00 Swale, cracking 0.10

RP 3.00 – 3.25 Ready Mix Road Approach 0.25

RP 3.31 – 3.45 Cut slope, cracking 0.14

RP 3.85 – 3.95 US Highway 191 Intersection 0.10

Subtotal 0.66 Miles 0.75 Miles

Total 1.41 Miles

As the above table indicates, the extents of encountering or creating high risk and/or very high risk unstable subgrades during construction are in miles because project stationing was not determined. A pickup truck odometer beginning at the south end was used to estimate these extents and, therefore, must be considered approximate.

High risk and very high risk extents are indicated in the table. If construction occurs in the spring, then we recommend using both extents. If construction is scheduled for late summer and fall, then consideration of only including the very high risk extents can be considered.

We wish to point out that the recommended method to determine the extents for subexcavation and placement of the stabilized pavement section is by proof rolling during construction. These extents can vary, especially when considering the weather prior to and during construction, frequency and size of construction equipment, drainage during construction, and many other conditions dependent on nature and construction methods.

D.4.e. Daylighting Base and Select Borrow. To avoid creating a bathtub, we recommend the stabilized pavement section be daylighted at the inslopes. Daylighting these aggregates provides drainage if surface water seeps through cracks in the pavement.

D.5. Existing Gravel Surfacing The existing gravel surfacing observed on the south end of the project near the Regina Road intersection is quite contaminated with clay. We do not recommend it be reused as base course for the project. The existing gravel surface can be reused as gravel surfacing.

D.6. Specifications We recommend that all earthwork, construction, recycling, and paving be performed in accordance with

FP-14, Specifications for Construction of Roads and Bridges on Federal Highway Projects.

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E. Procedures

E.1. Drilling and Sampling The penetration test borings were performed on May 9 and 10, 2019, with a truck-mounted core and auger drill. Sampling for the borings was conducted in accordance with ASTM D 1586, "Penetration Test and Split-Barrel Sampling of Soils." Using this method, we advanced the borehole with hollow-stem auger to the desired test depth. Then a 140-pound hammer falling 30 inches drove a standard, 2-inch OD split-barrel sampler a total penetration of 1 1/2 feet below the tip of the hollow-stem auger. Because these blow counts are important, the blows recorded in each 6-inch increment of advance are indicated on the boring logs and are an index of soil strength characteristics.

E.2. Soil Classifications The existing pavement and soils encountered by the borings by drilling were visually classified and logged by a senior geotechnical engineer in accordance with ASTM D 2488, "Standard Practice for

Description and Identification of Soils (Visual-Manual Procedures)." A summary of the ASTM classification system is attached.

E.3. Groundwater Observations About 10 minutes after taking the final sample in the bottom of a boring, our driller probed through the hollow-stem auger to check for the presence of groundwater. Immediately after withdrawal of the auger the driller again probed the depth to water or cave in. The boring was then backfilled and the surface was patched with cold-mix asphalt pavement.

F. General Recommendations

F.1. Basis of Recommendations The analyses and recommendations submitted in this report are based upon the data obtained from the soil borings performed at the locations indicated. Often, variations occur between these borings, the nature and extent of which do not become evident until additional exploration or construction is conducted. This is especially true for existing pavement thicknesses. A reevaluation of the recommendations in this report should be made after performing on-site observations during construction to note the characteristics of any variations. The variations may result in additional earthwork and pavement costs, and it is suggested a contingency be provided for this purpose.

Project 18-3762G Page 15

It is recommended we be retained to perform the observation and testing program for the site preparation phase of this project. This will allow correlation of the soil conditions encountered during construction to the soil borings, and will provide continuity of professional responsibility.

F.2. Review of Design This report is based on the design of the proposed alignment as related to us for preparation of this report.

It is recommended we be retained to review the geotechnical and pavement aspects of the designs and specifications. With the review, we will evaluate whether any changes in design have affected the validity of the recommendations, and whether our recommendations have been correctly interpreted and implemented in the design and specifications.

F.3. Groundwater Fluctuations We made water level observations in the borings at the times and under the conditions stated on the boring logs. These data were interpreted in the text of this report. The period of observation was relatively short, and fluctuation in the groundwater level may occur due to rainfall, flooding, irrigation, spring thaw, drainage, and other seasonal and annual factors not evident at the time the observations were made. Design drawings and specifications and construction planning should recognize the possibility of fluctuations.

F.4. Use of Report This report is for the exclusive use of Robert Peccia & Associates and the Federal Highway

Administration (FHWA) to use to design the proposed improvements and prepare construction documents. In the absence of our written approval, we make no representation and assume no responsibility to other parties regarding this report. The data, analyses, and recommendations may not be appropriate for other structures or purposes. We recommend parties contemplating other structures or purposes contact us.

F.5. Level of Care Services performed by SK Geotechnical Corporation personnel for this project have been conducted with that level of care and skill ordinarily exercised by members of the profession currently practicing in this area under similar budget and time restraints. No warranty, expressed or implied, is made.

Appendix

PARTIAL TOPOGRAPHIC SKETCH

South of Malta, Montana

Drawn by: SK/MBMG Date 11/8/18

Project: 18-3762G

Scale: None FIGURE

Sheet 1 of 1 1

Reference: Malta West and Malta East 7.5 Minute Topo Maps, U.S. Geological Survey, North American Datum of 1983 (NAD83)

North Beginning of Project RP 0.0

End of Project RP 4.0

GEOLOGIC MAP

South of Malta, Montana

Drawn by: SK/USGS Date 11/8/18

Project: 18-3762G

Sheet 1 of 1 1

Beginning of Project RP 0.0

End of Project RP 4.0

Ql

Geologic Map of the Malta 30’x60’ Quadrangle, Northeast Montana By Robert N. Bergantino, 1999

North `

BORING LOCATION SKETCH

MT Phillips 364(1), Short Oil Road

South of Malta, Montana

Drawn by: Google/SKG Date 6/13/19

Project: 18-3762G

Sheet of

Boring ST-1 at RP 0.0. Boring ST-2 at RP 0.05.

Boring ST-3 at RP 0.5. Boring ST-4 at RP 1.0.

Boring ST-5 at RP 1.5. Boring ST-6 at RP 2.0.

Boring ST-7 at RP 2.5. Boring ST-8 at RP 3.0.

Boring ST-9 at RP 3.1. Boring ST-10 at RP 3.4.

Boring ST-11 at RP 3.7. Boring ST-12 at RP 3.9.

Fill slope near RP 0.35. Fill slope near RP 2.3.

Fill slope near RP 3.5. Fill slope near RP 3.72.

Descriptive Terminology

Standard D 2487

Classification of Soils for Engineering Purposes

(Unified Soil Classification System)

Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Soil Classification Group Symbol Group Name B

Coarse- Grained Soils More than 50% retained on No.

200 sieve

Gravels More than 50% of coarse fraction retained on No. 4 sieve

Clean Gravels Less than 5% fines C

CU ≥ 4 and 1 ≤ CC ≤ 3 E GW Well graded gravel F

CU < 4 and/or 1 > CC > 3 E GP Poorly graded gravel F

Gravels with Fines More than 12% fines C

Fines classify as ML or MH GM Silty gravel F, G, H

Fines classify as CL or CH GC Clayey gravel F, G, H

Sands 50% or more of coarse fraction passes No. 4 sieve

Clean Sands Less than 5% fines D

CU ≥ 6 and 1 ≤ CC ≤ 3 E SW Well graded sand I

CU < 6 and/or 1 > CC > 3 E SP Poorly graded sand I

Sands with Fines More than 12% fines D

Fines classify as ML or MH SM Silty sand G, H, I

Fines classify as CL or CH SC Clayey sand G, H, I

Fine- Grained Soils 50% or more passes the No. 200 sieve

Silts and Clays Liquid Limit less than 50

Inorganic PI > 7 and plots on or above "A" line J CL Lean clay K, L, M

PI < 4 or plots below "A" line J ML Silt K, L, M

Organic Liquid limit – oven dried < 0.75 Liquid limit – not dried

OL

Organic clay K, L, M, N

Organic silt K, L, M, O

Silts and Clays Liquid limit 50 or more

Inorganic PI plots on or above "A" line CH Fat clay K, L, M

PI plots below "A" line MH Elastic siltK, L, M

Organic Liquid limit – oven dried < 0.75 Liquid limit – not dried OH Organic clayK, L, M, P

Organic siltK, L, M, Q

Highly Organic Soils Primarily organic matter, dark in color, and organic odor PT Peat

A

B

C

D

E

F

G

Based on the material passing the 3" (75 mm) sieve.

If field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group name.

Gravels with 5 to 12% fines require dual symbols GW-GM well-graded gravel with silt GW-GC well-graded gravel with clay GP-GM poorly graded gravel with silt GP-GC poorly graded gravel with clay Sands with 5 to 12% fines require dual symbols.

SW-SC well-graded sand with clay SP-SM poorly graded sand with silt SP-SC poorly graded sand with clay

CU = D60 / D10

CC = (D30)2 / (D10 x D60)

If soil contains ≥ 15% sand, add "with sand" to group name.

If fines classify as CL-ML, use dual symbol GC-GM or

SC-SM.

H

I

J

K

L

M

N

O

P

Q

If fines are organic, add "with organic fines" to group name.

If soil contains ≥ 15% gravel, add "with gravel" to group name.

If Atterberg limits plot in hatched area, soil is a CL-ML, silty clay.

If soil contains 15 to 29% plus No. 200, add "with sand" or "with gravel", whichever is predominant.

If soil contains ≥ 30% plus No. 200 predominantly sand, add "sandy" to group name.

If soil contains ≥ 30% plus No. 200 predominantly gravel, add "gravelly" to group name.

PI ≥ 4 and plots on or above "A" line.

PI < 4 or plots below "A" line.

PI plots on or above "A" line.

PI plots below "A" line.

Particle Size Identification Boulders .......................................... over 12" Cobbles .......................................... 3" to 12" Gravel coarse ......................................... 3/4" to 3" fine ........................................ No. 4 to 3/4" Sand coarse ................................ No. 4 to No. 10 medium ........................... No. 10 to No. 40 fine ................................ No. 40 to No. 200 Silt ................................. No. 200 to .005 mm Clay ................................ less than .005 mm Relative Density of Cohesionless Soils very loose ..................................... 0 to 4 BPF loose ........................................... 5 to 10 BPF medium dense .......................... 11 to 30 BPF dense ........................................ 31 to 50 BPF very dense ................................. over 50 BPF Consistency of Cohesive Soils very soft ....................................... 0 to 1 BPF soft ............................................... 2 to 3 BPF rather soft ..................................... 4 to 5 BPF medium ........................................ 6 to 8 BPF rather stiff ................................... 9 to 12 BPF stiff ........................................... 13 to 16 BPF very stiff ................................... 17 to 30 BPF hard ........................................... over 30 BPF Moisture Content (MC) Description rather dry MC less than 5%, absence of moisture, dusty moist MC below optimum, but no visible water wet Soil is over optimum MC waterbearing Granular, cohesionless or low plasticity soil with free water, typically near or below groundwater table very wet Cohesive soil well over OMC, typically near or below groundwater table

Drilling Notes Standard penetration test borings were advanced by 3¼" or 4¼" ID hollow-stem augers, unless noted otherwise. Standard penetration test borings are designated by the prefix "ST" (split tube). Hand auger borings were advanced manually with a 2 to 3" diameter auger to the depths indicated. Hand auger borings are indicated by the prefix "HA."

Sampling. All samples were taken with the standard 2" OD split-tube sampler, except where noted. TW indicates thin-walled tube sample.

CS indicates California tube sample. BS indicates bulk sample.

BPF. Numbers indicate blows per foot recorded in standard penetration test, also known as "N" value. The sampler was set 6" into undisturbed soil below the hollow-stem auger. Driving resistances were then counted for second and third 6" increments and added to get BPF.

Where they differed significantly, they were separated by backslash (/). In very dense/hard strata, the depth driven in 50 blows is indicated.

WH. WH indicates the sampler penetrated soil under weight of hammer and rods alone; driving not required.

Note. All tests were run in general accordance with applicable ASTM standards.

Laboratory Tests DD Dry density, pcf WD Wet density, pcf OC Organic content, % LL Liquid limit PL Plastic limit PI Plasticity index P200 % passing 200 sieve MC Natural moisture content, % MDD Maximum dry density (Proctor), pcf OMC Optimum moisture content (Proctor), % qu Unconfined compressive strength, psf UCS Unconfined compressive strength, psi qp Pocket penetrometer strength, tsf

October 30, 2018

13.0

18.0

16.0

0" to 5½" 3" minus Gravel Surfacing

SANDY LEAN CLAY, stiff to soft, olive brown, moist to wet, low plasticity, trace gravel (Fill).

SANDY LEAN CLAY, soft to stiff, olive brown to brown, wet, low to medium plasticity, trace gravel.

(Glacial Till)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 2.0' immediately after withdrawal of auger.

13.0

18.0

16.0

CL

CL

0.5

3.0

5.5

Bag sample 0-5"

83% Recovery

77% Recovery

72% Recovery

8/7/3

2/2/2

3/5/7

SCALE:5/10/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-1

0.0

LOCATION:

ST-1 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 0.0, 48°17'36.67"N, 107°51'22.16"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/1

8/

2.1

15.3

12.0

0" to 3" Asphalt pavement

3" to 5" ¾" minus base course

5" to 8¾" 3" minus subbase course

SANDY LEAN CLAY, stiff to firm, olive brown, moist to wet, low plasticity, some gravel. (Fill)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 2.7' immediately after withdrawal of auger.

2.1

15.3

12.0

CL

0.4

0.7

1.0

5.5

66% Recovery

Bulk Sample 1' - 4'

LL=28, PL=14, PI=14

P200=54% MDD=120 pcf

OMC=12.3%

CBR=4.2

94% Recovery

83% Recovery

8/4/4

5/5/5

4/3/2

SCALE:5/10/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-2

0.0

LOCATION:

ST-2 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 0.05, 48°17'39.55"N, 107°51'22.27"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/1

8/

3.8

9.5

7.8

0" to 2½" Asphalt Pavement 2½" to 4½" ¾" minus base course 4½" to 8¾" 3" minus subbase course

SANDY LEAN CLAY, stiff, brown, moist, low plasticity, trace gravel. (Fill)

SILTY SAND, very loose to loose, olive brown to dark brown, moist, fine-grained, subrounded. (Fill)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 2.5' immediately after withdrawal of auger.

3.8

9.5

7.8

CL

SM

0.2 0.4

0.7

1.5

5.5

83% Recovery

89% Recovery

83% Recovery

6/5/7

3/2/2

3/3/2

SCALE:5/10/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-3

0.0

LOCATION:

ST-3 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 0.5, 48°18'3.02"N, 107°51'23.03"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/2

1/

13.3

17.7

10.4

0" to 2½" Asphalt pavement 2½" to 6" ¾" minus base course

6" to 10½" 3" minus base course

SANDY LEAN CLAY, firm to very stiff, olive brown to brown, moist to wet, low plasticity, trace gravel. (Fill)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 2.1' immediately after withdrawal of auger.

13.3

17.7

10.4

CL

0.2

0.5

0.9

5.5

6/3/3

2/5/6

8/7/9

SCALE:5/10/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-4

0.0

LOCATION:

ST-4 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 1.0, 48°18'25.04"N, 107°51'38.80"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/1

8/

17.2

16.0

13.4

0" to 3" Asphalt pavement

3" to 5½" ¾" minus base course 5½" to 9¾" 3" minus base course

CLAYEY SAND, loose, olive brown, wet, low plasticity, fine- to coarse-grained, rounded, some gravel. (Fill)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 2.3' immediately after withdrawal of auger.

17.2

16.0

13.4

SC

0.3 0.5

0.8

5.5

67% Recovery

Bulk Sample 1' to 4'

LL=26, PL=11, PI=15

P200=47% MDD=120.8 pcf

OMC=11.5%

CBR=4.8

72% Recovery

89% Recovery

8/3/3

2/2/5

3/3/2

SCALE:5/10/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-5

0.0

LOCATION:

ST-5 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 1.5, 48°18'51.25"N, 107°51'44.83"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/1

8/

12.8

15.2

0" to 3" Asphalt pavement

3" to 5" ¾" minus base course 5" to 9½" 3" minus base course

CLAYEY SAND, medium dense to loose, olive brown, wet to moist, low plasticity, fine- to coarse-grained, rounded, some gravel. (Fill)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 1.7' immediately after withdrawal of auger.

12.8

15.2

SC

0.3 0.4

0.8

5.5

0% Recovery

83% Recovery

94% Recovery

11/6/6

6/5/8

2/3/4

SCALE:5/9/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-6

0.0

LOCATION:

ST-6 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 2.0, 48°19'15.03"N, 107°51'49.59"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/1

8/

14.2

13.2

0" to 3" Asphalt pavement

3" to 4½" ¾" minus base course 4½" to 9" 3" minus subbase course

CLAYEY SAND with GRAVEL, loose, olive brown, wet to moist, low plasticity, fine- to coarse-grained, rounded. (Fill)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 2.4' immediately after withdrawal of auger.

14.2

13.2

SC

0.3 0.4

0.8

5.5

44% Recovery

Bulk Sample 1' to 4'

LL=24, PL=10, PI=14

P200=39% MDD=128.9 pcf

OMC=9.6%

CBR=4.0

61% Recovery

89% Recovery

10/5/2

2/2/3

2/3/3

SCALE:5/9/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-7

0.0

LOCATION:

ST-7 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 2.5, 48°19'43.08"N, 107°51'59.53"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/1

8/

4.5

5.3

7.7

0" to 3" Asphalt pavement patch (appeared to be cold mix) 3" to 5½" ¾" minus base course POORLY GRADED SAND, medium dense to loose, light brown, rather dry, fine-grained, rounded.

(Fill)

SILTY SAND with GRAVEL, medium dense, brown, moist, fine to coarse-grained, rounded. (Fill)

SANDY LEAN CLAY, firm, dark brown, moist, low plasticity. (Fill)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 2.0' immediately after withdrawal of auger.

4.5

5.3

7.7

SP

SM

CL

0.2

0.5

2.5

3.5

5.5

Boring performed in recently patched area.

83% Recovery

78% Recovery

78% Recovery

12/10/7

4/12/8

3/3/3

SCALE:5/9/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-8

0.0

LOCATION:

ST-8 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 3.0, 48°20'6.65"N, 107°51'59.72"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/1

8/

12.8

14.9

15.9

0" to 2" Asphalt pavement 2" to 5½" ¾" minus base course

5½" to 9½" 3" minus subbase course

SANDY LEAN CLAY, firm to stiff, olive brown, moist to wet, trace gravel and iron oxide. (Fill)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 1.8' immediately after withdrawal of auger.

12.8

14.9

15.9

CL

0.2

0.5

0.8

5.5

61% Recovery

83% Recovery

89% Recovery

5/4/4

2/2/5

3/4/5

SCALE:5/9/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-9

0.0

LOCATION:

ST-9 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 3.1, 48°20'14.68"N, 107°51'59.76"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/1

8/

13.7

14.2

12.6

0" to 1¾" Asphalt pavement 1¾" to 4½" ¾" minus base course

4½" to 8½" 3" minus subbase course

SANDY LEAN CLAY, firm to stiff, olive brown to brown, moist, trace gravel and salts. (Fill)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 1.8' immediately after withdrawal of auger.

13.7

14.2

12.6

0.1

0.4

0.7

5.5

Severe alligator cracking in this area.

72% Recovery

Bulk Sample 1' to 4'

LL=34, PL=10, PI=24

P200=55% MDD=119.4 pcf

OMC=11.9%

CBR=1.8

100% Recovery

94% Recovery

7/3/2

2/3/4

4/5/8

SCALE:5/9/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-10

0.0

LOCATION:

ST-10 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 3.4, 48°20'30.15"N, 107°52'8.74"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/1

8/

8.7

9.3

9.5

0" to 2¾" Asphalt pavement 2¾" to 5" ¾" minus base course 5" to 11" 3" minus subbase course

SANDY LEAN CLAY, stiff to firm, olive brown, moist, low plasticity, trace gravel. (Fill)

END OF BORING

Water not observed with 4' of hollow-stem auger in the ground.

Water not observed to dry cave-in depth of 2.1' immediately after withdrawal of auger.

8.7

9.3

9.5

CL

0.2 0.4

0.9

5.5

67% Recovery

Subgrade 1' to 4'

83% Recovery

89% Recovery

8/5/4

3/2/3

7/8/6

SCALE:5/9/19 1" = 1'DRILLED BY: S. Robertson

Elev.

PROJECT: 18-3762G

PAVEMENT EVALUATION

Short Oil Road, MT Phillips 364(1) S. of Malta, MT

WL

MC

qp RemarksSymbol

BORING:

Depth

DATE:

ST-11

0.0

LOCATION:

ST-11 page 1 of 1

L O G O F B O R I N G

Description of Materials

18-3762G

METHOD: 3 1/4" HSA, Automatic

BPF

2511 Holman Avenue P. O. Box 80190

Billings, MT 59108-0190 Phone: 406.652.3930

Fax: 406.652.3944

RP 3.7, 48°20'41.88"N, 107°52'20.65"W

B O

R

IN

G B

P F

W L-

M C

Q P

2.

G

P J

L A

G N

N N

.G

D T

/1

8/

10.3

10.2

0" to 2¾" Asphalt pavement 2¾" to 4½" ¾" minus base course 4½" to 10¼" 3" minus…