Pavement Investigation Report - Soils_

REPORT OF

PAVEMENT INVESTIGATION

FOR

BRANCH COUNTY INTERMEDIATE SCHOOL DISTRICT

PARKING LOT RECONSTRUCTION

CITY OF COLDWATER

BRANCH COUNTY

MICHIGAN

FEBRUARY 14, 2024

AR Engineering

5725 Venture Park Drive, Suite A

Kalamazoo, Michigan 49009

Project No. 2023.2218

February 14, 2024

AR Engineering 5725 Venture Park Drive, Suite A Kalamazoo, Michigan, 49009

Attention: Mr. Spencer O’Dell, P.E.

Regarding: Branch County Intermediate School District

Parking Lot Reconstruction - Pavement Investigation Coldwater, Branch County, Michigan Project No. 2023.2218

Dear Mr. O’Dell:

Soils & Structures, Inc. is pleased to present this pavement investigation report for the Branch County Intermediate School District (ISD) parking lot rehabilitation project located in the City of Coldwater, Branch County, Michigan.

The investigation included a total of ten (10) test borings that extended to a depth of 4.0 feet.

The test borings were conducted in accordance with industry standards for pavement sampling. In-situ Dynamic Cone Penetrometer (DCP) testing was performed in accordance with

ASTM D 6951.

The report, test boring location plan, and test boring logs are enclosed. The report provides recommendations for pavement cross section designs, thicknesses, material properties and the anticipated service life of the proposed systems. Construction notes and drainage considerations have also been included.

We appreciate the opportunity to provide engineering services to AR Engineering. If you have any questions regarding this report, please contact our office.

Sincerely, Soils & Structures, Inc. Reviewed by:

Gretchen Anderson, Staff Geologist Don R. Dunkin, P.E.

Contents

Location of Pavement Investigation Purpose of Investigation Design Information Tests Performed Description of Existing Pavement Profile, Subgrade and Groundwater Conditions Description of Groundwater Conditions Analysis and Recommendations I. Full Reconstruction (20 Years) with Hot-Mix Asphalt Pavement Sections II. Full Depth Reclamation (15 to 20 Years) with Hot-Mix Asphalt Pavement Sections III. Crush & Shape (15 Years) with Hot-Mix Asphalt Pavement Sections IV. Full Depth Mill & Overlay (12 to 15 Years) with Hot-Mix Asphalt Pavement Sections General Hot-Mix Asphalt (HMA) Recommendations Drainage Considerations for Pavement Areas Quality Control Testing General Conditions & Reliance

Appendix Test Boring Location Diagram

Test Boring Logs (B-1 through B-10) Laboratory Tests

General Soil Information

Page 3 – Branch County ISD Parking Lot Reconstruction– Pavement Investigation

Project 2023.2218 – February 14, 2024

Location of Pavement Investigation

The investigation was conducted at the Branch County Intermediate School District facility. The facility is located at 370 Morse Street in the City of Coldwater, Branch County, Michigan.

Purpose of Investigation

The purpose of this investigation is to provide pavement rehabilitation recommendations for the parking lot and associated access drives.

Design Information

Rehabilitation of the parking lot and associated access drives has been proposed. The footprint of the project area is approximately 9,100 square yards.

The pavements for the parking lot are expected to be subjected to primarily passenger vehicle traffic and occasional commercial truck traffic (mainly snow removal equipment, garbage trucks and delivery vehicles). An estimate of 250,000 lifetime Equivalent Single-Axle Loads (ESALs) was assumed for the recommended standard-duty hot mix asphalt pavement (HMA) sections.

The pavements for the access drives are expected to be subjected to mixed passenger vehicle and truck traffic (primarily school buses and snow removal equipment). An estimate of 750,000 lifetime ESALs was assumed for the recommended heavy-duty HMA sections.

If traffic volume counts are known or collected and are significantly greater than anticipated, then Soils & Structures should be contacted so that the pavement recommendations included in this report may be reviewed and revised if necessary.

Tests Performed

The pavement investigation included a total of ten (10) test borings extended to a depth of approximately four (4.0) feet. The shallow test borings were conducted in accordance with industry standards for pavement sampling. The locations were determined by Soils & Structures, Inc. A Geoprobe® was used to obtain samples.

Prior to performing the pavement test borings, the soil strength was evaluated in-situ at test borings B-1 through B-10 using a United States Army Corps of Engineers Dynamic Cone Penetrometer (USACE DCP) to a depth of three (3.0) feet. The DCP is a steel rod 5/8-inch in diameter with a pointed cone end that is driven into the subgrade using a sliding hammer. The weight of the hammer can be adjusted from 17.6 pounds to 10.1 pounds if weaker soils are encountered. This rate of penetration is used to estimate a California Bearing Ratio (CBR) value for the soil, which is used to interpret support conditions for the subgrade. Discussion of results will follow in further sections. Results of the DCP tests are included in the Appendix along with soil boring information. DCP testing was performed in accordance with ASTM D 6951.

Soil samples were classified according to the Unified Soil Classification System. This method is a standardized system for classifying soil according to its engineering properties. Please refer to the appendix of this report for the Unified Classification System Chart. The classification is shown in the on the test boring logs.

Page 4 – Branch County ISD Parking Lot Reconstruction– Pavement Investigation

Laboratory testing consisted of natural moisture content and sieve (particle size) analysis. The tests were performed on representative soil samples. The tests were performed in accordance with applicable ASTM standards. The moisture content documents the presence of groundwater. The sieve test determines the particle distribution which is used to classify the soil and estimate its properties.

Description of Existing Pavement Profile, Subgrade and Groundwater Conditions

The pavement profile of the parking lot consists of 1.75 to 5.25 inches of asphalt with an average thickness of 4.1 inches over 1.75 to 18.75 inches of aggregate base with an average thickness of

9.25 inches. The aggregate base consists predominantly of fine-to-coarse sand with clay and natural gravel. The aggregate base consists of natural aggregates with asphalt millings at the surface in the area of B-2 through B-4, B-6, B-7, and B-9. Results of the sieve analysis performed on a representative sample of the aggregate base taken from test boring B-1 and B-3 shows that it meets or is closely approximates MDOT 23A dense-graded aggregate gradation criteria. The measured fines content of the tested samples ranged from 8.8 to 8.9 percent. Based on visual classification, however, there are some localized areas where the aggregate base has a higher clay and silt content. DCP results for the aggregate base showed CBR values from 18.8 to 89.2 percent with an average value of 36.2 percent, indicating generally poor support conditions for an aggregate base.

The aggregate base appears to bear directly on subgrade soils. The subgrade consists predominately of sand with varying fines content. There is a mixture of clean and clayey sands. Results of the sieve analysis performed on a sample of the subgrade taken from test boring B-6 shows that it meets MDOT Class II gradation criteria. Results of the sieve analysis performed on sample from test boring B-2 shows that it did not meet any MDOT granular material gradation criteria due to a high fines content. The measured fines content of the tested samples ranged from 4.6 to 21.6 percent. A pocket of sandy clay is present in the area of B-4. DCP results for the subgrade showed CBR values from 16.6 to 67.3 percent with an average value of 31.3 percent, indicating good support conditions.

Description of Groundwater Conditions

Groundwater was not encountered at the time of drilling. Long term groundwater monitoring was not performed as part of this investigation.

Analysis and Recommendations

Based on visual observations, in-situ testing and laboratory testing the pavements are nearing the end of their design life. The asphalt pavements exhibit severe distresses that have resulted from a combination of age, deterioration due to climatic influences, moisture infiltration, and variable section thickness.

A partial-depth mill and overlay is not recommended for any of the pavement areas as the existing HMA at the site is too thin to support the necessary equipment. The extent of full depth cracking observed in the existing asphalt will result in reflective cracking through a thin overlay which will dramatically reduce the service life. A partial depth mill and overlay will probably not be cost effective.

The following reconstruction options are recommended:

1. FULL RECONSTRUCTION UTILIZING HMA PAVEMENTS, (20-year design life)

This option would require complete removal of existing pavements and the aggregate base. The site would then be regraded and proof-rolled prior to placement of the sand subbase, new aggregate base, Page 5 – Branch County ISD Parking Lot Reconstruction– Pavement Investigation and HMA overlay. Areas of soft or yielding soil would be either removed and replaced (undercutting) or mechanically stabilized using geo-grids. This option is the most reliable HMA pavement option with respect to long term serviceability and the most flexible with regards to establishing new grades, however it will be the most expensive.

2. FULL DEPTH RECLAMATION WITH CEMENT STABILIZED BASE COURSE, (15 to 20-year design life)

Full depth reclamation (FDR) with a cement stabilized base course (SBC) is often used as a method to recycle and improve the quality of existing pavement materials prior to resurfacing. The process has been proven to decrease construction costs on unstable sites or sites with inadequate existing pavement cross sections, as well as decreasing construction time and reducing contingencies associated with conventional full reconstruction. This process consists of milling off a pre-determined portion of the existing asphalt prior to pulverizing the remaining asphalt, aggregate base, and an engineered amount of subgrade soils into a homogenous mixture. The material would then be regraded to accommodate the new HMA overlay.

The salvaged base would then be chemically stabilized using Portland cement. After fine grading the stabilized base to provide positive drainage, the resulting stabilized base course would then be directly resurfaced with new HMA pavements. This option would be least intrusive with regards to maintaining access to the facility as excavation would be minimal. Additionally, this process could be held as a contingency in lieu of base repairs if base repair requirements become excessive for other construction options.

Due to the high structural support contribution of the SBC, the required HMA overlay thickness could likely be slightly reduced relative to the full reconstruction option, further adding to cost savings. If this option is selected, the generation of a site-specific laboratory mix design is recommended to fully assess the materials for appropriate additive types and application rates. For estimating and bidding purposes, an application rate of fifty (50) pounds per square yard using Type I Portland cement may be assumed.

3. CRUSH-AND-SHAPE WITH HMA OVERLAY, (15-year design life)

This process would involve pulverizing the existing HMA pavement and aggregate base to generate a homogenous mixture of materials. The pulverizing process should extend to a depth of approximately

8.0 inches. The inclusion of asphalt millings in the base will help offset potential support issues caused by the high sand and fines content of the existing aggregate. Excess pulverized material could be used to increase the section thickness of the existing aggregate base in any areas where it is deficient by way of undercutting. The site would be regraded to accommodate the proposed new HMA pavement.

Since the site grades are constrained by existing hardscapes a substantial amount of reclaimed material will need to be removed which will limit the effectiveness of this option. The salvaged base would be compacted and thoroughly proof-rolled prior to resurfacing with new HMA pavement. Areas failing the proof roll should be undercut and backfilled using the excess pulverized material. Efforts should be made during construction to minimize repetitive loading and overloading of the exposed pulverized section with construction traffic.

4. FULL DEPTH MILL AND OVERLAY, (12 to 15-year design life)

This process would involve milling off the existing HMA pavements. The exposed aggregate base would then be compacted and thoroughly proof-rolled prior to resurfacing with new HMA pavement. This option would likely have the lowest upfront cost, but will have the shortest service life. The sandy nature

Page 6 – Branch County ISD Parking Lot Reconstruction– Pavement Investigation of the aggregate base, and poorly drained subgrade soils will likely cause constructability challenges.

As such, a 30% contingency is recommended for base improvements and undercutting as needed to address deficiencies. The aggregate base improvements should be expedited to avoid inclement weather saturating the exposed base once the milling process has been completed. Additionally, efforts should be made during construction to minimize repetitive loading and overloading of the exposed base with construction traffic.

Four recommended pavement cross-sections are presented in this section of the report:

1. A full reconstruction option utilizing HMA pavements;

2. A full-depth reclamation with cement stabilization option utilizing HMA pavements;

3. A crush-and-shape option utilizing HMA pavements; and

4. A full depth mill and overlay utilizing HMA pavements.

These recommendations were developed based on the discussions and assumptions included in this REPORT and the design procedures outlined in the “AASHTO Guide for Design of Pavement Structures - 1993.” The final pavement section should be designed based on actual traffic volumes and the owner specific performance requirements. The recommended pavement section materials listed in Tables One through Four refer to and should comply with the standard material designations included in applicable MDOT specifications and guidelines, including the 2020 MDOT “Standard Specifications for Construction.”

The recommended HMA cross sections for are based off of a minimum subgrade CBR value of

5.0 percent. Although in most areas the CBR is higher than 5.0 percent, is widely understood that correlations between subgrade reaction moduli and CBR are not reliable at higher CBR ranges.

Therefore, a CBR of 5.0 percent, which correlates to a subgrade resilient modulus of 6,000 psi, was assumed for the existing subgrade.

A calculated service life loading of 250,000 ESALS was assumed for the standard-duty pavement section. Based on these values, a minimum-required structural number (SN) of 2.71 will be necessary to support the design traffic loading for the passenger vehicle areas. A calculated service life loading of 750,000 ESALS was assumed for the heavy-duty pavement section. Based on these values, a minimum-required structural number (SN) of 3.20 will be necessary to support the design traffic loading for the bus drop-off/pick-up loop.

Recommended cross-sections meet the minimum-required design structural numbers. Cross-sections have been designed to withstand the assumed traffic loads mentioned above, as well as environmental stresses experienced due to Michigan’s wet freeze/thaw cycles. An 80% reliability was assumed for all pavement sections. Initial and terminal serviceability values are 4.5 and 2.25, respectively.

For all the full reconstruction, crush and shape, and full depth mill options contingencies should be held for undercutting of soft or yielding soils. Positive drainage should be maintained in exposed soils to avoid accumulation of precipitation. The subgrade should be thoroughly proof-rolled prior to the placement of subsequent pavement layers. Areas of soft or yielding soil should either be removed and replaced or mechanically stabilized using geo-grid. The recommended geogrid product is a triaxial product such as Tensar TX-140. Use of geogrid in lieu of undercutting would require new angular (crushed) aggregate as aggregate interlock is required to take full advantage of the grids.

Triaxial geogrid will limit the required depth of excavations. The minimum thickness of aggregate over the geogrid should be 12.0 inches for HMA pavements.

Page 7 – Branch County ISD Parking Lot Reconstruction– Pavement Investigation

I. Full Reconstruction (20 Years) with Hot-Mix Asphalt Pavement Sections

Cross-section recommendations for the full reconstruction option are listed in Table One. The design life also assumes that incremental maintenance repairs such as joint sealing, localized patching, and/or sealcoating is performed as required throughout the life of the pavement.

Table 1: Recommended Pavement Sections – Full Reconstruction

Pavement Cross Section

Materials

Parking Lot Bus Route

Material Thickness (in) Material Thickness (in)

HMA Wearing Course

4EML 2.0 4EML 2.5

HMA Leveling Course

4EML 2.0 4EML 2.5

Aggregate Base1

21AA 8.0 21AA 10.0

Sand Subbase Class II 12.0 Class II 12.0

Note 1: The recommended aggregate base material for HMA pavements is MDOT 21AA crushed limestone. Natural gravel meeting MDOT 22A specifications or a 21AA Modified crushed concrete product may also be used, but the aggregate base thickness should be increased by 20.0 percent to accommodate lower-quality material properties.

II. Full Depth Reclamation (15 to 20 Years) with Hot-Mix Asphalt Pavement Sections

Cross-section recommendations are listed in Table Two. The design life also assumes that incremental maintenance repairs such as joint sealing, localized patching, and/or sealcoating is performed as required throughout the life of the pavement.

Table 2: Recommended Pavement Sections – Full Depth Reclamation

Cross Section

Materials

Parking Lot Bus Route

Material Thickness (in) Material Thickness

(in)

HMA Wearing Course

4EML 1.5 4EML 2.0

HMA Leveling Course

4EML 2.0 4EML 2.5

Aggregate Base

Stabilized Base

Course (Per Mix Design)

12.0

Stabilized Base

Course (Per Mix Design)

12.0

Page 8 – Branch County ISD Parking Lot Reconstruction– Pavement Investigation

III. Crush & Shape (15 Years) with Hot-Mix Asphalt Pavement Sections

Cross-section recommendations are listed in Table Three. The design life also assumes that

Table 3: Recommended Pavement Sections – Crush & Shape

Cross Section

Materials

Parking Lot Bus Route

Material Thickness (in) Material Thickness (in)

HMA Wearing Course

4EML 2.0 4EML 2.5

HMA Leveling Course

4EML 2.0 4EML 2.5

Aggregate Base Salvaged 8.0 - MIN Salvaged 8.0 - MIN

IV. Full Depth Mill & Overlay (12 to 15 Years) with Hot-Mix Asphalt Pavement Sections

Cross-section recommendations are listed in Table Four. The design life also assumes that

Table 4: Recommended Pavement Sections – Full Depth Mill & Overlay

Cross Section

Materials

Parking Lot Bus Route

Material Thickness (in) Material Thickness (in)

HMA Wearing Course

4EML 2.0 4EML 2.5

HMA Leveling Course

4EML 2.0 4EML 2.5

Aggregate Base1

Existing 8.0 - MIN Existing 8.0 - MIN

Note 1: While MDOT 21AA crushed limestone is generally the recommended product, it will not help improve the service life for this rehabilitation option. Natural gravel meeting MDOT 22A specifications or a 21AA Modified crushed concrete product may be utilized for undercuts. Due to the relatively thin existing aggregate base, this option may pose constructability issues.

General Hot-Mix Asphalt (HMA) Recommendations

The recommended 4EML mix has been selected based on its robust structural characteristics and resistance to wheel path rutting / tire marks. The use of a 4EML product will result in a rougher wearing surface. If a smoother finish is desired to accommodate recreation (roller skates/skateboarding), a finer wearing course mix such as a 5EML can be considered. The 5EML will be more susceptible to exhibiting distresses especially during periods of higher temperatures early on in its service life. Soils & Structures should be notified if a 5EML will be considered so that this report can be reviewed and revised as necessary. To help prevent issues with production or performance of any mix, it is recommended that the Job Mix Formula (JMF) be forwarded to Soils & Structures for review prior to placement.

Page 9 – Branch County ISD Parking Lot Reconstruction– Pavement Investigation

The paving contractor should submit the proposed mix design and any associated backup data to the owner and engineer-of-record for approval prior to placement.

For all recommended long-term pavement sections, MDOT Tier I RAP specifications should be utilized for both the wearing and leveling courses with performance grade PG 64-28 asphalt binder. MDOT Tier II RAP specifications may be applied to the leveling course but should utilize performance grade PG 58-28 asphalt. MDOT 2020 Standards specify the use of a performance grade PG 64-34 or PG 58-34 asphalt binder in combination with Tier II RAP specifications, however this is not recommended due to limited regional availability and high costs associated with these asphalt binders. Performance grade PG 58-28 asphalt binder is an acceptable alternative for a pavement utilizing Tier II RAP content specifications.

Target void content should be 3.5 percent for both the wearing and leveling courses. The asphalt pavement should be compacted to 94 to 97 percent of the theoretical maximum density (determined via the Superpave “Rice” Method). Additionally, a tack coat of SS -1h emulsion should be applied between each laid asphalt layer at a rate of 0.1 gallon/square yard.

The pavement sections should be constructed in accordance with the Michigan Department of Transportation “2020 Standard Specifications for Construction” as well as applicable state and local requirements. Support conditions and compaction should be assessed during construction in accordance with the “Quality Control and Testing” section of this report. This assessment should occur prior to installation of individual pavement layers (i.e. prior to placement of aggregate base and subsequent pavement layers).

Drainage Considerations for Pavement Areas

The pavement areas should be properly drained to minimize the effects of frost heaving and the loss of subgrade support due to water infiltration. The parking lot and access drives should be sloped at a minimum of 1.5 percent toward regional low points with catch basins or toward drainage swales or curb inlets.

For all of the recommended strategies, underdrain will be a critical component to extending the life of the pavement, especially due to the higher fines content of subgrade soils at this site.

Underdrain should be installed as cutoff drains adjacent to green scape areas sloping towards the pavement to prevent seepage under the section. Ring wraps should be installed adjacent to stormwater structures where they form low points in the pavement and finger drains should be extended at pedestrian crossings other hardscape features as necessary to mitigate infiltration and frost heave. Soils and Structures can review proposed drain tile layouts and details on request.

Underdrains should consist of a 6-inch diameter perforated pipe. The underdrain trench should extend at least 18.0 inches below the aggregate base. The trench should be lined in a non-woven geotextile fabric with proper overlap. The wrapped portion of the drain tile should be backfilled with MDOT 34R peastone with the top portion of the trench backfilled with MDOT 21AA limestone aggregate. This detail is an expanded drain tile recommendation and is probably more expensive than typical pavement drainage specifications, which typically call for a 4-inch perforated pipe.

However, these specifications will provide a longer service life for the drain system.

Page 10 – Branch County ISD Parking Lot Reconstruction– Pavement Investigation

Quality Control Testing

Pavement subgrade, subbase and/or aggregate base should be proof rolled using a fully -loaded tri-axle dump truck prior to aggregate base and pavement placement.

Compaction tests (ASTM D 6938) are recommended to confirm that backfill, subgrade, sand subbase, aggregate base and/or stabilized base course in pavement areas are compacted to specified densities. When fill is being placed compaction tests should be performed at the rate of one test per 300 cubic yards of fill and throughout the depth of the fill with a minimum of five tests at each 1.0-foot elevation interval. The recommended testing frequency in the pavement subgrade and aggregate base course is one test per 2,500 square feet. The maximum density should be determined in accordance with ASTM D 1557 or ASTM D 4253 procedures. A dynamic cone should not be substituted for compaction tests for evaluating backfill.

Compaction testing should be performed by technicians supervised by a registered geotechnical engineer. Proof rolling and stabilization should be performed by a senior technician or field engineer under the supervision of a registered geotechnical engineer.

Asphalt quality control testing should adhere to the 2020 MDOT Standards for Construction. Asphalt temperatures during placement should be at least 275 degrees Fahrenheit; material that arrives at temperatures below 250 degrees Fahrenheit shall be rejected. Asphalt density testing should be performed with a nuclear density gauge at a minimum rate of one test per 4,500 square feet of pavement. At least five total verification cores in each course should be taken to assess relative compaction, calibrate the nuclear density gauge, and evaluate thickness. A minimum of two loose mix samples per mix per day should be taken at the plant and delivered to the quality-assurance firm’s laboratory for vacuum extraction-gradations. The asphalt contractor should provide a minimum of two

(2) theoretical maximum density verifications per day. Additionally, areas that display poor workmanship, which may include (but are not limited to) segregation, “cold screed scrapes”, wearing courses not flush with curbs or rims, roller marks, shoving, smearing or tearing of the mat, flushing, or excessive cold joints should be repaired or replaced by the contractor immediately.

Per the 2020 MDOT Standards for Construction asphalt should not be placed when moisture (i.e., rain or surface water) will prevent curing. Asphalt should never be placed on surfaces less than 35 degrees Fahrenheit or over frost. Whenever surface temperatures fall below 50 degrees Fahrenheit the 2020 MDOT Weather Limitations should be referenced for application rate requirements.

Once a rehabilitation option has been selected, please contact Soils & Structures and we will prepare a set of project specific Construction notes to be included in the bid documents if desired.

General Conditions & Reliance

The report was prepared in accordance with generally accepted practices of the geotechnical engineering profession. The scope of work consisted of performing ten test borings providing soil related recommendations for the site pavements. The scope of work did not include an environmental study or wetland determination.

The report and the associated test borings were prepared specifically for the previously described project and site. Soils & Structures should be consulted if a significant change in the scope of the project is made, or if a specific design criterion (such as traffic counts) is known or changed.

Page 11 – Branch County ISD Parking Lot Reconstruction– Pavement Investigation

The test borings represent point information and may not encountered all soil types and material present on this site. This report does not constitute a guarantee of the soil of the groundwater conditions or that the test boring is an exact representation of the soil or groundwater conditions at all points on this site.

The descriptions and recommendations contained in this report are based on an interpretation of the test borings and laboratory tests. The test borings should not be used independently of the report. If soil conditions are encountered which are significantly different from the test borings. Soils & Structures should be consulted for additional recommendations. The report and test borings may be relied upon by AR Engineering for the design, construction, permitting, and financing associated with the construction of new pavement at Branch County Intermediate School District located in Coldwater, Branch County, Michigan. The use of the report and test borings by third parties not associated with this project or for other sites has not been agreed upon by Soils & Structures. Soils & Structures does not recommend or consent to third party use of reliance of the report of test borings unless allowed to review the proposed use of these materials. Unless obtained in writing, consent to third party use should not be assumed. Third parties using the report or test boring logs do so at their own risk and are offered no guarantee or promise of indemnity.

Appendix

Test Boring Location Diagram

Test Boring Logs (B-1 through B-10)

Laboratory Tests General Soil Information

TES

T B

O R

IN

G

LO

C

A

TIO

N D

IA

G

R A

M

P roject N am e: B ranch C ounty IS

D P arking Lot R econstruction–

P avem ent Investigation Location: C oldw ater, B ranch C ounty, M ichigan P roject N um ber: 2

.2

D ate: 1

.2

.2

N ot to S cale

N ote: The background im age is an aerial photograph of the site.

Locations are approxim ate.

Project Name

Project Number 2023.2218 Date 12/27/2023 Client AR Engineering

Boring ID Boring Type Geoprobe®

2.25 Location See BLD

# of Blows Cumulative Penetration

(mm)

Hammer Type

Soil Type CBR % Cumulative Penetration

(inch)

0 230 1 SP-SC 2.3

5 270 1 SP-SC 28.4 3.8

6 315 1 SP-SC 30.6 5.6

7 355 1 SP-SC 41.5 7.2

6 400 1 SP-SC 30.6 8.9

5 440 1 SC 28.4 10.5

6 470 1 SC 48.1 11.7

10 510 1 SC 61.8 13.3

6 545 1 SC 40.5 14.7

6 585 1 SC 34.9 16.2

6 630 1 SC 30.6 18.0

6 675 1 SC 30.6 19.8

8 720 1 SC 42.2 21.5

8 760 1 SC 48.1 23.1

5 805 1 SC 24.9 24.9

5 865 1 SC 18.1 27.3

3 935 1 SC 8.6 30.0

3 985 1 SC 12.5 32.0

2 1020 1 SC 11.8 33.4

From To Thickness Classification 0 1.5 1.5

1.5 2.25 0.75

2.25 10 7.75 SP-SC

10 44 34 SC

Branch County ISD Parking Lot Reconstruction - Pavement Investigation

DCP Starting Depth (in)

Description ASPHALT WEARING COURSE - Intact ASPHALT LEVELING COURSE - Intact

B-1

AGGREGATE BASE - Fine-to-Coarse SAND with Natural Gravel and Clay, brown

Comments: Groundwater not encountered.

Fine-to-Coarse Clayey SAND with Gravel, brown

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

1.0 10.0 100.0

D ep th (i n)

CBR (%)

CBR VS DEPTH

Date 12/27/2023 Client AR Engineering

Boring ID Boring Type Geoprobe®

1.75 Location See BLD

# of Blows Cumulative Penetration

(mm)

Hammer Type

Soil Type CBR % Cumulative Penetration

(inch)

0 205 1 SP-SC 1.8

10 240 1 SP-SC 71.8 3.1

15 265 1 SP-SC 100.0 4.1

10 305 1 SP-SC 61.8 5.7

6 335 1 SP-SC 48.1 6.9

5 380 1 SC 24.9 8.6

5 415 1 SC 33.0 10.0

6 450 1 SC 40.5 11.4

6 480 1 SC 48.1 12.6

8 520 1 SP-SM 48.1 14.2

10 560 1 SP-SM 61.8 15.7

13 620 1 SP-SM 52.7 18.1

10 675 1 SP-SM 43.3 20.3

10 730 1 SP-SM 43.3 22.4

10 790 1 SC 39.3 24.8

8 850 1 SC 30.6 27.1

8 915 1 SC 27.9 29.7

5 955 1 SC 28.4 31.3

6 1000 1 SC 30.6 33.0

From To Thickness Classification 0 0.75 0.75

0.75 1.75 1

1.75 7.5 5.75 SP-SC

7.5 14 6.5 SC

14 23 9 SP-SM

23 48 25 SC

ASPHALT LEVELING COURSE - Intact

Branch County ISD Parking Lot Reconstruction - Pavement Investigation

B-2 DCP Starting Depth (in)

Description ASPHALT WEARING COURSE - Intact

Comments: Groundwater not encountered.

AGGREGATE BASE - Fine-to-Coarse SAND with Gravel(Natural and Asphalt Millings) and Clay, black

AGGREGATE BASE - Fine-to-Coarse Clayey SAND with Gravel, brown Fine-to-Coarse SAND with Gravel and Silt, brown Fine-to-Medium Clayey SAND, brown

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

1.0 10.0 100.0

D ep th (i n)

Date 12/27/2023 Client AR Engineering

Boring ID Boring Type Geoprobe®

4.25 Location See BLD

# of Blows Cumulative Penetration

(mm)

Hammer Type

Soil Type CBR % Cumulative Penetration

(inch)

0 280 1 SP-SC 4.3

3 320 1 SP-SC 16.0 5.8

5 365 1 SP-SC 24.9 7.6

5 420 1 SP-SC 19.9 9.8

5 505 1 SC 12.2 13.1

4 610 1 SC 7.5 17.2

8 655 1 SC 42.2 19.0

12 700 1 SC 66.4 20.8

8 760 1 SC 30.6 23.1

10 815 1 SC 43.3 25.3

6 870 1 SC 24.4 27.5

6 920 1 SC 27.2 29.4

6 965 1 SC 30.6 31.2

6 1000 1 SC 40.5 32.6

From To Thickness Classification 0 2 2 2 4.25 2.25

4.25 8 3.75 SP-SC

8 13 5 SP-SC

13 21 8 SC

21 29 8 SC

29 48 19 SP

ASPHALT LEVELING COURSE - Delaminated

Branch County ISD Parking Lot Reconstruction - Pavement Investigation

B-3 DCP Starting Depth (in)

Description ASPHALT WEARING COURSE - Intact

Comments: Groundwater not encountered.

AGGREGATE BASE - Fine-to-Coarse SAND with Gravel (Natural and Asphalt Millings) and Clay, dark brown

AGGREGATE BASE - Fine-to-Medium SAND with Gravel and Clay, brown Fine-to-Coarse Clayey SAND with trace Gravel, brown Fine-to-Coarse Clayey SAND, brown Fine-to-Coarse SAND, brown

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

1.0 10.0 100.0

D ep th (i n)

Date 12/27/2023 Client AR Engineering

Boring ID Boring Type Geoprobe®

4.25 Location See BLD

# of Blows Cumulative Penetration

(mm)

Hammer Type

Soil Type CBR % Cumulative Penetration

(inch)

0 270 1 SP-SC 4.3

5 300 1 SP-SC 39.3 5.4

5 350 1 SP-SC 22.2 7.4

5 380 1 SP-SC 39.3 8.6

6 435 1 SP-SC 24.4 10.7

6 500 1 CL 20.3 13.3

6 560 1 CL 22.2 15.7

3 625 1 CL 7.4 18.2

1 660 1 CL 2.8 19.6

1 700 1 CL 2.2 21.2

3 780 1 SP 7.4 24.3

2 825 1 SP 8.9 26.1

3 875 1 SP 12.5 28.1

3 905 1 SP 22.2 29.3

6 945 1 SP 34.9 30.8

7 985 1 SP 41.5 32.4

7 1015 1 SP 57.2 33.6

From To Thickness Classification 0 1 1 1 4.25 3.25

4.25 12 7.75 SP-SC

12 23 11 CL

23 48 25 SP

ASPHALT LEVELING COURSE - Delaminated

Branch County ISD Parking Lot Reconstruction - Pavement Investigation

B-4 DCP Starting Depth (in)

Description ASPHALT WEARING COURSE - Intact

Comments: Groundwater not encountered.

AGGREGATE BASE - Fine-to-Coarse SAND with Gravel (Natural and Asphalt Millings) and Clay, black

Sandy Lean CLAY with Gravel, brown Fine-to-Coarse SAND with Gravel, brown

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

1.0 10.0 100.0

D ep th (i n)

Date 12/27/2023 Client AR Engineering

Boring ID Boring Type Geoprobe®

4.25 Location See BLD

# of Blows Cumulative Penetration

(mm)

Hammer Type

Soil Type CBR % Cumulative Penetration

(inch)

0 270 1 SP-SC 4.3

8 305 1 SP-SC 55.9 5.6

10 335 1 SP 85.3 6.8

12 375 1 SP 75.8 8.4

15 415 1 SP 97.3 10.0

15 450 1 SP 100.0 11.3

20 495 1 SP 100.0 13.1

25 550 1 SP 100.0 15.3

25 600 1 SP 100.0 17.2

25 670 1 SP 92.2 20.0

25 745 1 SP 85.3 23.0

12 800 1 SC 53.1 25.1

8 855 1 SC 33.7 27.3

8 900 1 SC 42.2 29.1

3 940 1 SC 16.0 30.6

3 985 1 SC 14.1 32.4

3 1030 1 SC 14.1 34.2

From To Thickness Classification 0 2 2 2 4.25 2.25

4.25 6 1.75 SP-SC

6 23 17 SP

23 45 22 SC

45 48 3 SC

ASPHALT LEVELING COURSE - Intact

Branch County ISD Parking Lot Reconstruction - Pavement Investigation

B-5 DCP Starting Depth (in)

Description ASPHALT WEARING COURSE - Intact

Comments: Groundwater not encountered.

AGGREGATE BASE - Fine-to-Coarse SAND with Natural Gravel and Clay, brown AGGREGATE BASE - Fine-to-Coarse SAND with Gravel and trace Clay, brown Fine-to-Coarse Clayey SAND with Gravel, brown Moisture Content 14.6 % Fine-to-Coarse Clayey SAND, brown

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

1.0 10.0 100.0

D ep th (i n)

Date 12/27/2023 Client AR Engineering

Boring ID Boring Type Geoprobe®

4.75 Location See BLD

# of Blows Cumulative Penetration

(mm)

Hammer Type

Soil Type CBR % Cumulative Penetration

(inch)

0 300 1 SP-SC 4.8

4 355 1 SP-SC 15.5 6.9

6 390 1 SC 40.5 8.3

4 430 1 SC 22.2 9.9

4 495 1 SC 12.9 12.4

3 540 1 SC 14.1 14.2

3 585 1 SC 14.1 16.0

3 630 1 SC 14.1 17.7

4 680 1 SC 17.3 19.7

4 715 1 SP 25.7 21.1

4 760 1 SP 19.4 22.9

4 815 1 SP 15.5 25.0

4 885 1 SP 11.8 27.8

2 935 1 SP 7.9 29.8

2 990 1 SP 7.1 31.9

2 1030 1 SP 10.2 33.5

From To Thickness Classification 0 1.5 1.5

1.5 4.75 3.25

4.75 7.5 2.75 SP-SC

7.5 20 12.5 SC

20 48 28 SP

Comments: Groundwater not encountered.

AGGREGATE BASE - Fine-to-Coarse SAND with Gravel (Natural and Asphalt Millings) and Clay, dark brown

AGGREGATE BASE - Fine-to-Coarse Clayey SAND with Gravel, brown Fine-to-Coarse SAND with Gravel, brown

ASPHALT LEVELING COURSE - Intact

Branch County ISD Parking Lot Reconstruction - Pavement Investigation

B-6 DCP Starting Depth (in)

Description ASPHALT WEARING COURSE - Intact

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

1.0 10.0 100.0

D ep th (i n)

Date 12/27/2023 Client AR Engineering

Boring ID Boring Type Geoprobe®

4.75 Location See BLD

# of Blows Cumulative Penetration

(mm)

Hammer Type

Soil Type CBR % Cumulative Penetration

(inch)

0 270 1 SP-SC 4.8

5 320 1 SP-SC 22.2 6.7

6 355 1 SP-SC 40.5 8.1

8 405 1 SP-SC 37.5 10.1

8 465 1 SP-SC 30.6 12.4

8 525 1 SP-SC 30.6 14.8

8 590 1 SP-SC 27.9 17.3

6 640 1 SP-SC 27.2 19.3

6 700 1 SP-SC 22.2 21.7

5 760 1 SP-SC 18.1 24.0

3 810 1 SP-SC 12.5 26.0

4 885 1 SP-SC 11.0 29.0

3 935 1 SP-SC 12.5 30.9

3 1000 1 SP 9.3 33.5

From To Thickness Classification 0 2 2 2 4.75 2.75

4.75 6.5 1.75 SP-SC

6.5 31 24.5 SP-SC

31 48 17 SP

Comments: Groundwater not encountered.

AGGREGATE BASE - Fine-to-Coarse SAND with Gravel (Natural and Asphalt Millings) and Clay, dark brown

Fine-to-Medium SAND with Clay and trace Gravel, brown Fine-to-Coarse SAND with Gravel, brown

ASPHALT LEVELING COURSE - Delaminated and Vertical Crack

Branch County ISD Parking Lot Reconstruction - Pavement Investigation

B-7 DCP Starting Depth (in)

Description ASPHALT WEARING COURSE - Vertical Crack

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

1.0 10.0 100.0

D ep th (i n)

Date 12/27/2023 Client AR Engineering

Boring ID Boring Type Geoprobe®

5.25 Location See BLD

# of Blows Cumulative Penetration

(mm)

Hammer Type

Soil Type CBR % Cumulative Penetration

(inch)

0 295 1 SP-SC 5.3

4 340 1 SP-SC 19.4 7.0

4 370 1 SP-SC 30.6 8.2

6 405 1 SP 40.5 9.6

8 450 1 SP 42.2 11.4

8 505 1 SP 33.7 13.5

8 550 1 SP 42.2 15.3

8 615 1 SP 27.9 17.8

7 675 1 SP 26.3 20.2

7 740 1 SP 24.1 22.8

7 795 1 SP 29.0 24.9

7 860 1 SP 24.1 27.5

6 935 1 SP 17.3 30.4

3 980 1 SP 14.1 32.2

3 1025 1 SP 14.1 34.0

From To Thickness Classification 0 2.5 2.5

2.5 5.25 2.75

5.25 9 3.75 SP-SC

9 48 39 SP

Comments: Groundwater not encountered.

AGGREGATE BASE - Fine-to-Coarse SAND with Natural Gravel and Clay, dark brown Fine-to-Coarse SAND with trace Gravel and Cobble, brown

ASPHALT LEVELING COURSE - Intact

Branch County ISD Parking Lot Reconstruction - Pavement Investigation

B-8 DCP Starting Depth (in)

Description ASPHALT WEARING COURSE - Intact

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

1.0 10.0 100.0

D ep th (i n)

Date 12/27/2023 Client AR Engineering

Boring ID Boring Type Geoprobe® 5 Location See BLD

# of Blows Cumulative Penetration

(mm)

Hammer Type

Soil Type CBR % Cumulative Penetration

(inch)

0 320 1 SP-SC 5.0

5 370 1 SP-SC 22.2 7.0

6 415 1 SP-SC 30.6 8.7

8 465 1 SP-SC 37.5 10.7

9 510 1 SP-SC 48.1 12.5

9 560 1 SP-SC 42.8 14.4

9 630 1 SP-SC 29.4 17.2

9 700 1 SP-SC 29.4 20.0

12 745 1 SP-SC 66.4 21.7

12 795 1 SP-SC 59.0 23.7

10 850 1 SP-SC 43.3 25.9

10 925 1 SP-SC 30.6 28.8

8 985 1 SP-SC 30.6 31.2

8 1035 1 SP-SC 37.5 33.1

From To Thickness Classification 0 2.25 2.25

2.25 5 2.75

5 7.5 2.5 SP-SC

7.5 36 28.5 SP-SC

36 48 12 SP

Comments: Groundwater not encountered.

AGGREGATE BASE - Fine-to-Coarse SAND with Gravel (Natural and Asphalt Millings) and Clay, dark brown

AGGREGATE BASE - Fine-to-Coarse SAND with Clay and Gravel, brown Fine-to-Coarse SAND with trace Gravel, brown

ASPHALT LEVELING COURSE - Intact

Branch County ISD Parking Lot Reconstruction - Pavement Investigation

B-9 DCP Starting Depth (in)

Description ASPHALT WEARING COURSE - Intact

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

1.0 10.0 100.0

D ep th (i n)

Date 12/27/2023 Client AR Engineering

Boring ID Boring Type Geoprobe®

4.75 Location See BLD

# of Blows Cumulative Penetration

(mm)

Hammer Type

Soil Type CBR % Cumulative Penetration

(inch)

0 310 1 SP-SC 4.8

4 355 1 SP-SC 19.4 6.5

5 390 1 SP-SC 33.0 7.9

5 430 1 SP-SC 28.4 9.5

5 455 1 SP-SC 48.1 10.5

7 500 1 SC 36.3 12.2

7 545 1 SC 36.3 14.0

7 610 1 SC 24.1 16.6

7 645 1 SC 48.1 17.9

8 725 1 SC 22.2 21.1

7 810 1 SC 17.8 24.4

5 875 1 SC 16.5 27.0

3 920 1 SC 14.1 28.8

3 980 1 SP 10.2 31.1

3 1040 1 SP 10.2 33.5

From To Thickness Classification 0 1 1 1 4.75 3.75

4.75 12 7.25 SP-SC

12 30 18 SC

30 48 18 SP

Comments: Groundwater not encountered.

AGGREGATE BASE - Fine-to-Coarse SAND with Natural Gravel and Clay, brown Fine-to-Coarse Clayey SAND with trace Gravel, brown Fine-to-Coarse SAND with trace Gravel, brown

ASPHALT LEVELING COURSE - Intact

Branch County ISD Parking Lot Reconstruction - Pavement Investigation

B-10 DCP Starting Depth (in)

Description ASPHALT WEARING COURSE - Intact

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

1.0 10.0 100.0

D ep th (i n)

Project Number

Client

Date

Sample Location Sample ID Depth (ft)

Fine Medium Fine Silt

0.0% 25.4% 28.1% 21.5% 0.0%

D85 D50 D15 D10

9.8150 1.1382 0.1846 0.1004

Sieve % Passing Particle Size

(mm) % Passing

3 in. 100%

1 in. 100%

3/4 in. 98%

1/2 in. 90%

3/8 in. 84%

No. 4 72%

No. 8 62%

No. 16 51%

No. 30 40%

No. 50 24%

No. 100 12%

No. 200 8.8%

Technician Checked Approved

Particle Size Distribution Report

Branch County Intermediate School District Parking Lot Reconstruction - Pavement Investigation

2023.2218

AR Engineering

1/31/2024

B1 A Aggregate Base

% Sand % Fines

Coarse Coarse Clay

2.2% 14.1% 0.0%

D60 D30 Loss By Wash

2.1830 0.4206 8.8%

Particle Size Hydrometer Material Description

Fine-to-Coarse SAND with Gravel and Clay (SP-SC)

Remarks

Crushed Content = 37%

% +3" % Gravel bfritz mvanweelden mvanweelden

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0010.0100.1001.00010.000100.000

GRAVEL

SAND

Coarse Medium Fine

SILT CLAY

Material is closely approximated by MDOT 23A dense-graded aggregate gradation requirements.

Client

Date

Sample Location Sample ID Depth (ft)

Fine Medium Fine Silt

0.0% 35.3% 21.0% 18.8% 0.0%

D85 D50 D15 D10

17.1033 2.2863 0.1563 0.0891

Sieve % Passing Particle Size

(mm) % Passing

3 in. 100%

1 in. 100%

3/4 in. 91%

1/2 in. 70%

3/8 in. 65%

No. 4 56%

No. 8 50%

No. 16 45%

No. 30 37%

No. 50 21%

No. 100 15%

No. 200 8.9%

Technician Checked Approved

Particle Size Distribution Report

Branch County Intermediate School District Parking Lot Reconstruction - Pavement Investigation

2023.2218

AR Engineering

1/31/2024

B3 B 0.7

% Sand % Fines

Coarse Coarse Clay

8.9% 7.2% 0.0%

D60 D30 Loss By Wash

6.9788 0.4707 8.9%

Particle Size Hydrometer Material Description

Fine-to-Medium SAND with Gravel and Clay (SP-SC)

Remarks

% +3" % Gravel bfritz mvanweelden mvanweelden

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0010.0100.1001.00010.000100.000

GRAVEL

SAND

Coarse Medium Fine

SILT CLAY

Material meets MDOT 23A dense-graded aggregate gradation requirements.

Client

Date

Sample Location Sample ID Depth (ft)

Fine Medium Fine Silt

0.0% 41.3% 28.1% 10.9% 0.0%

D85 D50 D15 D10

12.2300 2.9756 0.4154 0.3150

Sieve % Passing Particle Size

(mm) % Passing

3 in. 100%

1 in. 100%

3/4 in. 100%

1/2 in. 86%

3/8 in. 74%

No. 4 59%

No. 8 47%

No. 16 36%

No. 30 24%

No. 50 9%

No. 100 6%

No. 200 4.6%

Technician Checked Approved

Particle Size Distribution Report

Branch County Intermediate School District Parking Lot Reconstruction - Pavement Investigation

2023.2218

AR Engineering

1/31/2024

B6 C 1.7

% Sand % Fines

Coarse Coarse Clay

0.0% 15.1% 0.0%

D60 D30 Loss By Wash

5.1571 0.8865 4.6%

Particle Size Hydrometer Material Description

Fine-to-Coarse SAND with Gravel (SP)

Remarks

% +3" % Gravel bfritz mvanweelden mvanweelden

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0010.0100.1001.00010.000100.000

GRAVEL

SAND

Coarse Medium Fine

SILT CLAY

Material meets MDOT Class II granular material

Client

Date

Sample Location Sample ID Depth (ft)

Fine Medium Fine Silt

0.0% 3.6% 24.8% 46.3% 0.0%

D85 D50 D15 D10

0.8354 0.2467 0.0520 0.0346

Sieve % Passing Particle Size

(mm) % Passing

3 in. 100%

1 in. 100%

3/4 in. 100%

1/2 in. 100%

3/8 in. 98%

No. 4 96%

No. 8 94%

No. 16 90%

No. 30 81%

No. 50 58%

No. 100 35%

No. 200 21.6%

Technician Checked Approved

Particle Size Distribution Report

Branch County Intermediate School District Parking Lot Reconstruction - Pavement Investigation

2023.2218

AR Engineering

1/31/2024

B2 D 1.9

% Sand % Fines

Coarse Coarse Clay

0.0% 3.7% 0.0%

D60 D30 Loss By Wash

0.3227 0.1217 21.6%

Particle Size Hydrometer Material Description

Fine-to-Medium Clayey SAND (SC)

Remarks

% +3" % Gravel bfritz mvanweelden mvanweelden

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0010.0100.1001.00010.000100.000

GRAVEL

SAND

Coarse Medium Fine

SILT CLAY

Material does not meet any MDOT granular material

General Information for Method of Field Investigation

The soil investigation was performed in accordance with industry standard practice methods for soil sampling. Soil sample collection utilized direct push and/or hand auger methods.

Field Testing

Mechanical direct push methods were utilized to sample the upper four (4.0) feet of the subgrade. Soil was sampled to greater depths in intervals of four (4.0) feet as needed. Hand auger soil sampling was performed in accordance with ASTM D 1452 as needed.

Prior to performing the test borings, the soil strength was evaluated in-situ using the United States Army Corps of Engineers Dynamic Cone Penetrometer (USACE DCP) to a depth of 3.0 feet. The DCP is a steel rod 5/8-inch in diameter with a pointed cone end that is driven into the subgrade using a sliding hammer.

The weight of the hammer can be adjusted from 17.6 pounds to 10.1 pounds if weaker soils are encountered. This rate of penetration is used to estimate a California Bearing Ratio (CBR) value for the soil, which is used to interpret support conditions of the subgrade. The DCP testing was performed in accordance with ASTM D 6951.

Laboratory Testing

Samples obtained during the investigation were tested in the laboratory for the moisture content, particle size distribution, Atterberg limits, and/or unconfined compressive strength (where applicable).

Moisture content of the soil is the percentage by weight of water contained in the soil sample compared to the dry weight of the solids of which the soil is composed. The moisture content of select samples is determined in accordance with ASTM D 2216.

Particle size distribution tests aid in predicting the engineering behavior of the in-situ soils by separating the individual particles into size ranges. Size distributions were developed by performing a sieve analysis in accordance with ASTM D 6913 for coarse grained soils or a hydrometer analysis in accordance with ASTM D 7928 for fine grained soils (as appropriate).

Atterberg tests determine the liquid and plastic limits of cohesive soils. The liquid limit of the soil is the water content where the soil is at the boundary of semi-liquid and plastic behavior. The plastic limit of the soil is the water content where the soil is at the boundary of plastic and semi-solid behavior. The plasticity index can be calculated from the liquid and plastic limits. Atterberg testing was performed in accordance with ASTM D 4318 as needed.

The primary purpose of the unconfined compressive strength test is to approximate quantitative values of compressive strength in soils possessing sufficient coherence to permit testing in the unconfined state. The shear strength of cohesive soils can be calculated from the results of the unconfined compressive strength test. Unconfined compressive strength testing was performed in accordance with ASTM D 2166 as needed.

Color

When the color of the soils is uniform throughout, the color will be recorded such as brown, gray, and black and may be modified by adjectives such as light and dark. If the soils predominant color is shaded by a secondary color, the secondary color precedes the primary color, such as gray-brown or yellow-brown. If two major and distinct colors are swirled throughout the soil, the colors will be modified by the term mottled; such as mottled brown and gray.

Water Observations

Depth of water recorded in the test boring is measured from the ground surface to the water surface at the time of soil sampling. Factors such as weather, soils porosity, etc., will cause the groundwater to fluctuate for both permeable and impermeable soils. Long term groundwater monitoring was not performed as part of this investigation unless stated otherwise.

Sample Type

If not otherwise indicated, the samples were acquired using direct push methods.

Classification Data – Laboratory data to assist in classification of soils and classification of soils characteristics; i.e., plastic limit or liquid limit

Particle Size Nomenclature

Particle Definition Particle Size

Cobbles Larger than 3” (75 mm)

Gravel – Coarse 3” to ¾” (75 to 19 mm)

Gravel – Fine 19.0 to 4.75 mm

Sand – Coarse 4.75 to 2.0 mm

Sand – Medium 2.0 to 0.425 mm

Sand - Fine 0.425 to 0.075 mm

Fines Smaller than 0.075 mm

Support Provided Relative to CBR

Aggregate Base (GP) CBR Percentage

Very Poor 0 – 30

Poor 30 – 60

Moderate 60 – 80

Good 80 and above

Subbase/Subgrade (SP, CL, ML) CBR Percentage

Very poor 0 – 3

Poor 3 - 5

Moderate 5 – 10

Good 10 and above

Unified Soil Classification System Chart

Major Divisions

Letter Symbol Typical Descriptions

C oa rs e

G ra in ed

S oi ls or e th an o f m at er ia l i s la rg er t ha n N o.

si ev e si ze

Gravel

More than 50% of coarse fraction retained on No.

4 sieve

Clean Gravel

(Less than 5% fines)

GW

Well-Graded gravels, gravel-sand mixtures, little or no fines

GP

Poorly-Graded gravels, gravel-sand mixtures, little or no fines

Gravel with Fines

(Greater than 12% fines)

GM Silty gravels, gravel-sand-silt mixtures

GC Clayey Gravels, gravel-sand-clay mixtures

Sand

More than 50% of coarse fraction passing No. 4 sieve

Clean Sand

(Less than 5% fines)

SW

Well-Graded sands, gravelly sands, little or no fines

SP

Poorly-Graded sands, gravelly sands, little or no fines

Sand with Fines

(Greater than 12% fines)

SM Silty sands, sand-silt mixtures

SC Clayey sands, sand-clay mixtures

Fi ne

G ra in ed

S oi ls or e th an o f m at er ia l i s sm al le r th an N o.

s ie ve s iz e

Lean Silts and Clays

Liquid limit less than 50

ML

Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts with slight plasticity

CL

Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays

OL Organic silts and organic silty clays of low plasticity

Fat Silts and Clays

Liquid limit greater than 50

MH

Inorganic silts, micaceous or diatomaceous fine sands or silty soils

CH

Inorganic clays of high plasticity, fat clays

OH Organic clays of medium to high plasticity,…