Table of Contents. Description

Transcription

1

2

3 Table of Contents Description Page A. Introduction...1 A.1. Project Description...1 A.2. Purpose...1 A.3. Background Information and Reference Documents...1 A.4. Site Conditions...1 A.5. Scope of Services...2 B. Results...3 B.1. Exploration Logs...3 B.1.a. Log of Boring Sheets...3 B.1.b. Geologic Origins...3 B.2. Geologic Profile...4 B.2.a. Materials Encountered...4 B.2.b. Groundwater...5 B.3. Laboratory Test Results...5 B.4. Ground Penetrating Radar...5 B.5. Falling Weight Deflectometer...6 B.5.a. Calculated R-values...6 B.5.b. Calculated Granular Equivalent...8 C. Discussion...11 C.1. Design Details...11 C.1.a. Expected Traffic and Pavement Type...11 C.1.b. Anticipated Grade Changes...11 C.1.c. Precautions Regarding Changed Information...12 C.2. Design and Construction Considerations...12 C.2.a. Visual Assessment of Pavement Surface Condition...12 C.2.b. Performing FDR (Segment 1)...12 C.2.c. Performing CIR (Segment 2)...12 C.2.d. Subgrade Conditions and Potential Improvements...13 D. Recommendations...14 D.1. Pavements...14 D.1.a. Design R-value...14 D.1.b. Materials and Compaction...14 D.2. Construction Quality Control...14 D.2.a. Excavation Observations for Subcuts...14 D.2.b. Materials Testing...14 D.2.c. Cold Weather Precautions...15 E. Procedures...15 E.1. Power Auger Borings...15

4 Table of Contents (continued) Description Page E.2. Material Classification and Testing...15 E.2.a. Visual and Manual Classification...15 E.2.b. Laboratory Testing...15 E.3. Groundwater Measurements...15 E.4. Ground Penetrating Radar...16 E.4.a. Data Collection...16 E.4.b. Analysis...16 E.5. Falling Weight Deflectometer...16 E.5.a. Testing...16 E.5.b. Analysis...16 F. Qualifications...17 F.1. Variations in Subsurface Conditions...17 F.1.a. Material Strata...17 F.1.b. Groundwater Levels...17 F.2. Continuity of Professional Responsibility...18 F.2.a. Plan Review...18 F.2.b. Construction Observations and Testing...18 F.3. Use of Report...18 F.4. Standard of Care...18 Appendix Soil Boring Location Sketch (5 sheets) Log of Boring Sheets (PAB-14 through PAB-25) Descriptive Terminology GPR Results

5 A. Introduction A.1. Project Description This Geotechnical Evaluation Report addresses the existing conditions on County Road (CR) 55 (Norell Avenue North) from County Road 61 (Myeron Road North) to CSAH 7 (Square Lake Trail North) in Stillwater Township and from CSAH 7 to CSAH 4 (170th Street North) in May Township, Washington County, Minnesota. These segments of CR 55 are scheduled for rehabilitation in 2015; cold in-place recycling (CIR) is being considered for the north segment (CSAH 7 to CSAH 4) and unstabilized full-depth reclamation (FDR) is a possible strategy for the south segment (CR 61 to CSAH 7). A.2. Purpose The purpose of the evaluation was to provide information and recommendations, including in-place pavement thicknesses, subgrade soil classification, and in-situ R-values calculated from previously collected Falling Weight Deflectometer (FWD) testing and laboratory testing, in order to assist Washington County in the rehabilitation of CR 55. A.3. Background Information and Reference Documents To facilitate our evaluation, we were provided with or reviewed the following information or documents: Aerial photographs available from the Internet. Washington County Geologic Atlas from the Minnesota Geological Survey. Pavement history information available from the County. FWD test data for the segment available from the County. A.4. Site Conditions Our referenced documents and past project experience in the general area indicate that the roadway is underlain mostly with glacial outwash of the Superior Lobe, with localized granular ice-contact deposits and glacial till, particularly on segment north of CSAH 7.

6 Washington County Public Works Project B December 17, 2014 Page 2 These segments of CR 55 are two-lane, two-way roadway with rural cross-sections classified as B minor and major collectors within the County system. The roadway topography is rolling with elevations very gradually rising from south to north. Annual average daily traffic (AADT) from 2012 is between 860 (north segment) and 1,050 (south segment). Previously available maintenance and construction history for this roadway shows the following: Segment 1: CR 61 to CSAH 7 1 1/2 inches of bituminous pavement (1994) 3 inches of bituminous pavement (1975) 9 inches Class 5 aggregate base (1975) 12 inches Select Granular (1975) Segment 2: CSAH 7 to CSAH 4 3 inches of bituminous pavement (1989) 8 inches Class 5 aggregate base (1989) A.5. Scope of Services Our scope of services for this project was originally submitted as a Proposal to Mr. Andrew Giesen of Washington County Public Works. We received authorization to proceed by receipt of a signed contract. Tasks performed in accordance with our authorized scope of services included: Staking and clearing exploration locations of underground utilities. Performing 12 power auger borings within the roadbed to 5 feet below the existing pavement surface. Providing appropriate traffic control during the field operations. Scanning the roadway with a 2.0-gigahertz, air-coupled Ground Penetrating Radar (GPR) in both directions of travel under the direction of a Professional Engineer. Performing analysis of previously collected FWD data to obtain estimates of subgrade R- value and effective in-situ granular equivalency (GE) values.

7 Washington County Public Works Project B December 17, 2014 Page 3 Performing up to six (6) moisture content tests and two (2) mechanical analyses (through a #200 sieve only) on select soil samples. Preparing this report containing a boring location sketch, exploration logs, summary of the geologic materials encountered, results of GPR and FWD testing, and a discussion of the results with regard to various rehabilitation options for the roadway. Exploration locations and surface elevations at the exploration locations were determined using GPS technology that utilizes the Minnesota Department of Transportation's (MnDOT) permanent GPS Virtual Reference Network (VRN). Our scope of services was performed under the terms of Contract Number 9119 with Washington County and included a similar evaluation program for several other 2015 projects; final reports for the other projects will be provided under separate cover as requested. B. Results B.1. Exploration Logs B.1.a. Log of Boring Sheets Log of Boring sheets for our power auger borings are included in the Appendix. The logs identify and describe the geologic materials that were penetrated and present the results of groundwater measurements. Strata boundaries were inferred from changes in the auger cuttings. The boundary depths likely vary away from the boring locations, and the boundaries themselves may also occur as gradual rather than abrupt transitions. B.1.b. Geologic Origins Without the benefit of undisturbed test samples such as from a standard penetration test, it is often difficult to discern between a disturbed soil (existing fill) and a native deposit, particularly when they are similar in composition. For this reason, we have not attempted to assign geologic origins to strata on the power auger boring logs.

8 Washington County Public Works Project B December 17, 2014 Page 4 B.2. Geologic Profile B.2.a. Materials Encountered The general geologic profile at the site consists (proceeding down from the ground surface) of bituminous pavement and aggregate base over soils including sandy lean clay, clayey sand and poorly graded sand with silt. Clayey sand or sandy lean clay were the most common subgrade types, extending to the 5-foot termination depth of borings Table 1 shows the pavement thickness measurements made by the drillers in the field. Table 1. Pavement Material Thicknesses Boring Measured Thicknesses (inches) Bituminous Aggregate Base* Total PAB PAB / /2 PAB PAB / /2 PAB Average, South Segment PAB / /2 PAB PAB PAB PAB PAB / /2 PAB Average, North Segment * Aggregate base was identified by drillers in the field. Laboratory tests to determine a classification (i.e. Class 5) of the aggregate base were not performed. It appears that the measured bituminous thicknesses are similar to those indicated by the pavement history for borings PAB-14 through PAB-18 (CR 61 to CSAH 7), while aggregate base was slightly thinner. Additionally, they are generally similar to those obtained from the GPR. We provide further discussion of this in section B.4 of this report. For the northern segment (CSAH 7 to CSAH 4), borings showed a significantly greater average thickness than shown by the pavement history and were only similar in a single location (PAB-21).

9 Washington County Public Works Project B December 17, 2014 Page 5 B.2.b. Groundwater Groundwater was not observed as our borings were advanced. Based on the moisture contents of the geologic materials encountered, it appears that groundwater was below the depths explored at the time of our exploration. Seasonal and annual fluctuations of groundwater, however, should be anticipated. B.3. Laboratory Test Results Results of our laboratory tests are presented below in Table 2. Table 2. Laboratory Test Results Boring Sample Depth (feet) Moisture Content (%) Percent Passing #200 Sieve Soil Classification PAB Silty sand (SM) PAB Silty sand (SM) PAB Poorly graded sand with silt (SP-SM) PAB Silty sand (SM) The moisture content results indicate the soils were likely below their optimum moisture contents for compaction. B.4. Ground Penetrating Radar We estimated pavement thicknesses from the GPR scans as shown in Table 3. See the Appendix of this report for a plot showing GPR-measured thickness by station. Table 3. GPR-Measured Thicknesses Bituminous (CR 61 to CSAH 7) Aggregate Base (CR 61 to CSAH 7) GPR Layer Thicknesses (inches) Bituminous (CSAH 7 to CSAH 4) Aggregate Base (CSAH 7 to CSAH 4) Average th --- Percentile th --- Percentile

10 Washington County Public Works Project B December 17, 2014 Page 6 Due to ambient noise and interference weakening the GPR signal, the aggregate base layer was very difficult to identify in the scan for both segments and has not been included above. Given the bituminous layer results, the thicknesses generally seem to match those obtained by soil borings and are in contradiction to the available information from project history. We therefore have utilized the boring and GPR data in considering strategies appropriate for CR 55. On the south segment, we observed a break (reduction) in bituminous thickness near the intersection with 120 th Street and continuing to the end of the segment at CSAH 7. See the GPR results in the attached Appendix for a bituminous thickness by GPR station. B.5. Falling Weight Deflectometer FWD testing was completed as described in section E.5 of this report. Test-by-test plots of the data presented below can be found in the Appendix. B.5.a. Calculated R-values The FWD-calculated R-value results are presented in Figures 1 and 2 and Tables 4 and 5. Note the thicknesses used for FWD analysis are derived from the boring and GPR information presented in this report, which may result in some differences from the results of analyses completed previously using pavement history.

11 Washington County Public Works Project B December 17, 2014 Page 7 Figure 1. FWD-calculated R-value (CR 61 to CSAH 7) R-value Test Station from CR 61 (miles) Figure 2. FWD-calculated R-value (CR 61 to CSAH 7) R-value Test Station from CSAH 7 (miles)

12 Washington County Public Works Project B December 17, 2014 Page 8 Table 4. FWD-based R-value Results (CR 61 to CSAH 7) Effective Subgrade R-value Average 24 Standard Deviation 6 Minimum 16 Maximum 36 15th Percentile 18 Table 5. FWD-based R-value Results (CSAH 7 to CSAH 4) Effective Subgrade R-value Average 19 Standard Deviation 5 Minimum 12 Maximum 34 15th Percentile 14 The subgrade trends slightly weaker from south to north, which is consistent with the observation that local glacial till deposits can be found north of CSAH 7, as well as the more frequent clayey soils encountered in the borings on this on this segment. B.5.b. Calculated Granular Equivalent The FWD-derived granular equivalent (GE) is presented in Figure 3 and 4 and Tables 6 and 7.

13 Washington County Public Works Project B December 17, 2014 Page 9 Figure 3. FWD-calculated Granular Equivalent (CR 61 to CSAH 7) Granular Equivalent (GE) Test Station from CR 61 (miles) Figure 4. FWD-calculated Granular Equivalent (CR 61 to CSAH 7) Granular Equivalent (GE) Test Station from CSAH 7 (miles)

14 Washington County Public Works Project B December 17, 2014 Page 10 Table 6. Effective GE Results (CR 61 to CSAH 7) Effective GE (inches) from FWD Data Average 15 Standard Deviation 5 Minimum 4 Maximum 23 15th Percentile 10 Table 7. Effective GE Results (CSAH 7 to CSAH 4) Effective GE (inches) from FWD Data Average 15 Standard Deviation 4 Minimum 4 Maximum 22 15th Percentile 12 All else equal, higher R-values from FWD will reduce the apparent contribution to structure attributed to the upper pavement layers. Conversely, R-values from FWD will tend to be conservative relative to laboratory values, resulting in greater attribution of overall stiffness to the upper layers in the form of GE. For CR 55, the R-value appears to reasonably represent the pavement based on our knowledge of pavement thicknesses, material and surface conditions and soil types. However, there are several areas of low GE in both segments that should be given additional consideration when selecting a pavement rehabilitation strategy approximately as shown below. Note that these points or segments represent the test results at discreet test points and would require further testing to delineate. Segment 1: CR 61 to CSAH 7 Between approximately and miles north of CR 61 Segment 2: CSAH 7 to CSAH , and miles north of CSAH 7 We further discuss options for these areas below in Section C.

15 Washington County Public Works Project B December 17, 2014 Page 11 C. Discussion C.1. Design Details C.1.a. Expected Traffic and Pavement Type Based on the previously cited traffic counts and using the State Aid ESAL Traffic Forecast Calculator, approximately 294,000 equivalent single axle loads (ESALs) should be expected for the 20-year bituminous design for the south segment (Segment 1). Approximately 243,000 ESALs can be expected for Segment 2. (Assumptions included a rural traffic distribution and traffic projection factor of 1.4.) Formal pavement thickness design is to be completed by the County; using MnDOT s FlexPave program, we estimate the GE requirement for a 20-year design to be about 18.6 and 17.5 inches (Segments 1 and 2, respectively) based on our recommended design R-values (section D.1.a.). The calculated intact GE (inches) based on thicknesses measured by the borings are near or slightly less than this required value, though the 15 th percentile (effective) value from FWD is short of the required value. It appears in both cases the pavement rehabilitation will require additional structure (i.e. a bituminous overlay) following CIR or FDR treatment. A likely overlay for CIR treatment on the north segment (Segment 2) is a 3-inch overlay, which can consist of two lifts of bituminous pavement (1 ½ inches each) or a single 2-inch lift of pavement overlaid by a 1-inch ultra-thin bonded overlay course. For FDR on the south segment (Segment 1), a 4-inch overlay appears to meet the structural requirements of the pavement. C.1.b. Anticipated Grade Changes We understand this project will be able to accommodate the small changes in grade for tie-ins to existing driveways and intersections. The use of stabilizing agents will reduce the changes in grade necessary to construct a structurally sufficient pavement section for CIR or FDR; however, we understand the County does not wish to remove reclaim on the southern segment, and the existing pavement section will not allow for a pre-mill of the pavements prior to CIR pavement stabilization on the north segment. We further discuss the appropriate pavement sections below.

16 Washington County Public Works Project B December 17, 2014 Page 12 C.1.c. Precautions Regarding Changed Information We have attempted to describe our understanding of the proposed construction to the extent it was reported to us by others. Depending on the extent of available information, assumptions may have been made based on our experience with similar projects. If we have not correctly recorded or interpreted the project details, we should be notified. New or changed information could require additional evaluation, analyses and/or recommendations. C.2. Design and Construction Considerations C.2.a. Visual Assessment of Pavement Surface Condition A detailed visual assessment of the pavement surface condition was not included in the scope of this evaluation. However, we were able to make general observations of the surface during the GPR operations, where we noted surface conditions that included cupped transverse cracking and some sand patching. The pavements appeared to be in fair condition overall. We were not able to confirm whether areas showing poor effective GE correlated with poorer than average pavement surface conditions. C.2.b. Performing FDR (Segment 1) If FDR (unstabilized) is selected for the segment between CR 61 and CSAH 7, a design reclamation depth of 8 inches is appropriate given the range of thicknesses encountered in the GPR and soil borings. We understand the County has no desire to pre-mill, which would result in a surface profile elevation about 4 inches above existing once the final overlay is applied. Exceptions may exist in areas where reduced structure will require further correction (discussed below). C.2.c. Performing CIR (Segment 2) Based on boring data and information obtained from the GPR, it appears there is adequate pavement section thickness to allow for the CIR approach on Segment 2. For CIR, the average bituminous thickness of approximately 5 to 5 1/2 inches is enough to allow a 4-inch-thick recycled mat assuming relatively intact bituminous layer (i.e. one free of significant bottomup stripping and other materials defects). We do not recommend pre-milling in order to leave enough materials to provide adequate support for the CIR equipment train. Certain areas may need a reduction to a 3-inch CIR given local conditions and changes. We recommend taking the following factors into consideration: A small change in grade (about 3 inches) will be necessary according to our preliminary pavement thickness calculations.

17 Washington County Public Works Project B December 17, 2014 Page 13 CIR will interrupt the existing crack pattern and mitigate reflective cracking to a degree, whereas an overlay or mill-and-overlay will not. This will likely result in reduced maintenance frequency and costs and additional pavement life. Often, though, CIR is not recommended for pavements with extensive surface cracking indicative of structural failures; in areas with extensive alligator cracking and rutting, CIR may not represent an ideal treatment. The relative incidence of these distresses should be established and confirmed using MnDOT pavement management data and visual evaluation, or supplemental coring required as part of the CIR mix design process. Subgrade corrections will generally not be necessary as part of the CIR process, though in the case of extreme subgrade issues, additional evaluation and possible supplementary repair may be warranted. In some cases there is significant deviation of the calculated GE value from the expected GE, which could be an indication of localized failure or structural compromise of the existing pavements. Test stations described in Section B.5.b represent the most extreme deviations of calculated GE from the GE expected from the as-built or measured pavement thicknesses. These areas of local weakness should be reviewed for pavement or subgrade failure as part of the project design. C.2.d. Subgrade Conditions and Potential Improvements Possible subgrade deficiencies or weakness was apparent in the FWD data for the roadway as discussed in Section B.5.b. Some variability should also be expected based on differences in soil type as silty, sandy and clayey soils were all encountered to varying extents within subgrade depths. It does not appear in general that corrections to the subgrade soil will be warranted for the CIR process with the exception of relatively isolated areas. If subcutting, removal, and/or replacement are necessary to correct structural deficiencies, the contractor should be prepared to potentially encounter variable soil types and moisture conditions as indicated by the borings. We recommend the use of the existing subgrade and aggregate base materials where possible in order to reduce the potential for differential effects and performance. We recommend selecting areas showing poor effective GE as supplemental locations for the cores required to perform the CIR mix designs.

18 Washington County Public Works Project B December 17, 2014 Page 14 D. Recommendations D.1. Pavements D.1.a. Design R-value As detailed above, we have backcalculated R-value results from FWD testing (section B.6), which represent in-situ values and will tend to be conservative relative to laboratory tests on re-molded soils. The 15 th percentile R-value from FWD was 14 and 18 for the north and south segments, respectively. With consideration of the sandy soils encountered in several borings, it is our opinion that an R-value of 20 can be used for thickness design purposes. D.1.b. Materials and Compaction We recommend performing a laboratory CIR mix design in order to establish stabilizer binder type, moisture and emulsion contents and maximum density for project materials. This design will require samples of the bituminous materials (via core). We recommend compacting the bituminous pavement overlay to at least 92 percent of the maximum theoretical Rice density. D.2. Construction Quality Control D.2.a. Excavation Observations for Subcuts We recommend having a geotechnical engineer observe all excavations related to pavement construction. The purpose of the observations is to evaluate the competence of the geologic materials exposed in the excavations. D.2.b. Materials Testing We recommend dynamic cone penetrometer (DCP) testing on embankment, aggregate base and reclaimed materials where subcuts and corrections are necessary. We recommend Gyratory tests on bituminous mixes to evaluate strength and air voids, and density tests to evaluate compaction. We recommend testing of CIR placement including gradations and moisture contents of recycled materials, checks for asphalt emulsion content and testing of the stabilized mixture.

19 Washington County Public Works Project B December 17, 2014 Page 15 D.2.c. Cold Weather Precautions CIR should be performed only when weather conditions are favorable, including temperatures of 50 degrees Fahrenheit and rising with no call for freezing temperatures in the 48-hour forecast. The work should also proceed only under dry conditions. E. Procedures E.1. Power Auger Borings The power auger borings were drilled with a truck-mounted core and auger drill equipped with solidstem auger. The borings were performed in accordance with ASTM D Samples were taken from auger cuttings as each boring was advanced, for which corresponding depths are shown on the boring logs. E.2. Material Classification and Testing E.2.a. Visual and Manual Classification The geologic materials encountered were visually and manually classified in accordance with ASTM Test Method D A chart explaining the classification system is attached. Samples were sealed in jars or bags and returned to our facility for review and storage. E.2.b. Laboratory Testing The results of the laboratory tests performed on geologic material samples are noted on or follow the appropriate attached exploration logs. The tests were performed in accordance with ASTM or AASHTO procedures. E.3. Groundwater Measurements The drillers checked for groundwater as the penetration test borings were advanced, and again after auger withdrawal. The boreholes were then backfilled or allowed to remain open for an extended period of observation as noted on the boring logs.

20 Washington County Public Works Project B December 17, 2014 Page 16 E.4. Ground Penetrating Radar E.4.a. Data Collection GPR scans of the pavement were collected according to GSSI, Inc. (manufacturer) SIR-20 processor settings established by MnDOT at an interval of one scan per lineal foot, approximately in the center of each travel lane. A calibration file, required for data post-processing, was collected at the beginning of the testing day. The RoadScan system from GSSI, Inc. allows for real-time monitoring of the GPR scan during testing, as well as for the entry of user marks to note roadway events such as bridges and intersections. This capability was used to mark and tie in the future pavement core/boring locations with GPS coordinates and the GPR scan to the extent possible. GPS data was also collected continuously along each route during the GPR scan. E.4.b. Analysis Pavement layer identification was accomplished using RADAN 7.0, a software package included with the GSSI, Inc. RoadScan system. The software includes tools to aid in delineating pavement layer transitions and automatically calculates their depths from the pavement surface using the calibration file(s) collected prior to or following testing. The identified layers were compared to the measured thicknesses from borings to validate the accuracy of those calculated by the software. E.5. Falling Weight Deflectometer E.5.a. Testing A Dynatest TM Model 8002E FWD was originally used for deflection testing. Data used for this roadway was collected under the terms of a separate contract with the County. Data collected by the FWD during testing include the deflections, impulse loads, pavement surface temperature, and the ambient air temperature. E.5.b. Analysis Effective R-value provides a measure of the stiffness of the pavement subgrade soil. R-value calculations are computed using the Hogg Model, which represents the subgrade as a soil mass of finite depth over a stiff layer. Hogg Model resilient modulus values are corrected for seasonal effects and for congruence to

21 Washington County Public Works Project B December 17, 2014 Page 17 backcalculated resilient modulus values, and finally converted to R-value by methods described in MnDOT Investigation 201. Hogg R-values are often conservative in granular soils, such as sands, and will reflect the moisture conditions in fine-grained soils such as clays. Because Hogg Model-calculated R-values are also relatively conservative compared to methods where an infinite half-space is considered, and seasonal adjustments are used, we make no further reduction of our results as they are presented. The effective GE from the FWD data was calculated using a method developed by MnDOT in their Investigation 195 Interim Report. The process uses the seasonally corrected deflection measured at the center of the FWD load and an estimate of the subgrade R-value from the test data. GE, when used for design of new pavement, provides a pavement structure in equivalent inches of MnDOT Class 5 aggregate base. F. Qualifications F.1. Variations in Subsurface Conditions F.1.a. Material Strata Our evaluation, analyses and recommendations were developed from a limited amount of site and subsurface information. It is not standard engineering practice to retrieve material samples from exploration locations continuously with depth, and therefore strata boundaries and thicknesses must be inferred to some extent. Strata boundaries may also be gradual transitions, and can be expected to vary in depth, elevation and thickness away from the exploration locations. Variations in subsurface conditions present between exploration locations may not be revealed until additional exploration work is completed, or construction commences. If any such variations are revealed, our recommendations should be re-evaluated. Such variations could increase construction costs, and a contingency should be provided to accommodate them. F.1.b. Groundwater Levels Groundwater measurements were made under the conditions reported herein and shown on the exploration logs, and interpreted in the text of this report. It should be noted that the observation period

22 Washington County Public Works Project B December 17, 2014 Page 18 was relatively short, and groundwater can be expected to fluctuate in response to rainfall, flooding, irrigation, seasonal freezing and thawing, surface drainage modifications and other seasonal and annual factors. F.2. Continuity of Professional Responsibility F.2.a. Plan Review This report is based on a limited amount of information, and a number of assumptions were necessary to help us develop our recommendations. It is recommended that our firm review the geotechnical aspects of the designs and specifications, and evaluate whether the design is as expected, if any design changes have affected the validity of our recommendations, and if our recommendations have been correctly interpreted and implemented in the designs and specifications. F.2.b. Construction Observations and Testing It is recommended that we be retained to perform observations and tests during construction, such as quality assurance during the CIR process. This will allow correlation of the conditions encountered during construction with those encountered by the borings, GPR and core information, and provide continuity of professional responsibility. F.3. Use of Report This report is for the exclusive use of the parties to which it has been addressed. Without written approval, we assume no responsibility to other parties regarding this report. Our evaluation, analyses and recommendations may not be appropriate for other parties or projects. F.4. Standard of Care In performing its services, Braun Intertec used that degree of care and skill ordinarily exercised under similar circumstances by reputable members of its profession currently practicing in the same locality. No warranty, express or implied, is made.

23 Appendix

24

25

26

27

28

29 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV SP- SM J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 5 inches of bituminous over 8 inches of aggregate base. POORLY GRADED SAND with SILT, trace Gravel, brown, moist. END OF BORING. METHOD: Water not observed while drilling. Boring then backfilled. Power Auger Description of Materials BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. DATE: 10/6/14 SCALE: 1" = 4' BPF WL PAB-14 Tests or Notes LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:02 B Braun Intertec Corporation, Bloomington MN PAB-14 page 1 of 1

30 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV SP- SM J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 5 1/2 inches of bituminous over 6 inches of aggregate base. POORLY GRADED SAND with SILT, trace Gravel, brown, moist. END OF BORING. METHOD: Water not observed while drilling. Boring then backfilled. Power Auger Description of Materials BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. DATE: 10/6/14 SCALE: 1" = 4' BPF WL PAB-15 Tests or Notes LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:02 B Braun Intertec Corporation, Bloomington MN PAB-15 page 1 of 1

31 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV SP- SM J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 5 inches of bituminous over 8 inches of aggregate base. POORLY GRADED SAND with SILT, fine- to medium-grained, trace Gravel, brown, moist. END OF BORING. METHOD: Water not observed while drilling. Water not observed to cave-in depth of 4 feet immediately after withdrawal of auger. Boring then backfilled. Power Auger Description of Materials BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. DATE: 10/6/14 SCALE: 1" = 4' BPF WL PAB-16 Tests or Notes LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:02 B Braun Intertec Corporation, Bloomington MN PAB-16 page 1 of 1

32 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV 1.0 SM 5.0 J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 3 1/2 inches of bituminous over 9 inches of aggregate base. SILTY SAND, fine- to medium-grained, trace Gravel, brown, moist. END OF BORING. METHOD: Water not observed while drilling. Water not observed to cave-in depth of 4 feet immediately after withdrawal of auger. Boring then backfilled. Power Auger Description of Materials BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. DATE: 10/6/14 SCALE: 1" = 4' BPF WL PAB-17 Tests or Notes LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:02 B Braun Intertec Corporation, Bloomington MN PAB-17 page 1 of 1

33 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV 1.2 SM 5.0 J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 6 inches of bituminous over 8 inches of aggregate base. SILTY SAND, fine-grained, trace Gravel, brown, moist. END OF BORING. METHOD: Water not observed while drilling. Water not observed to cave-in depth of 4 feet immediately after withdrawal of auger. Boring then backfilled. Power Auger Description of Materials BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. DATE: 10/6/14 SCALE: 1" = 4' BPF WL PAB-18 Tests or Notes LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:03 B Braun Intertec Corporation, Bloomington MN PAB-18 page 1 of 1

34 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV 1.0 SC 5.0 J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 4 1/2 inches of bituminous over 7 inches of aggregate base. CLAYEY SAND, fine- to medium-grained, brown, moist. END OF BORING. METHOD: Water not observed with 5 feet of hollow stem auger in the ground. Boring then backfilled. Power Auger Description of Materials BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. DATE: 10/7/14 SCALE: 1" = 4' BPF WL PAB-19 Tests or Notes LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:03 B Braun Intertec Corporation, Bloomington MN PAB-19 page 1 of 1

35 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV SP- SM J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 5 inches of bituminous over 8 inches of aggregate base. POORLY GRADED SAND with SILT, fine- to medium-grained, trace Gravel, brown, moist. END OF BORING. METHOD: Water not observed with 5 feet of hollow stem auger in the ground. Boring then backfilled. Power Auger Description of Materials BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. DATE: 10/7/14 SCALE: 1" = 4' BPF WL PAB-20 Tests or Notes LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:03 B Braun Intertec Corporation, Bloomington MN PAB-20 page 1 of 1

36 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol 0.8 PAV 1.5 SC CL 5.0 J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 5 inches of bituminous over 6 inches of aggregate base. CLAYEY SAND, trace roots, dark brown, moist. SANDY LEAN CLAY, trace Gravel, brown, moist. END OF BORING. METHOD: Water not observed with 5 feet of hollow stem auger in the ground. Water not observed to cave-in depth of 4 feet. Boring then backfilled. Power Auger Description of Materials BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. DATE: 10/7/14 SCALE: 1" = 4' BPF WL PAB-21 Tests or Notes LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:03 B Braun Intertec Corporation, Bloomington MN PAB-21 page 1 of 1

37 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV SP- SM J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 6 inches of bituminous over 8 inches of aggregate base. POORLY GRADED SAND with SILT, fine- to medium-grained, trace Gravel, reddish brown, moist. END OF BORING. METHOD: Power Auger Description of Materials Water not observed with 5 feet of hollow stem auger in the ground. DATE: Water not observed to cave-in depth of 4 feet immediately after withdrawal of auger. BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. 10/7/14 SCALE: 1" = 4' BPF WL PAB-22 Tests or Notes Boring then backfilled. LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:03 B Braun Intertec Corporation, Bloomington MN PAB-22 page 1 of 1

38 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV SP- SM SP- SM J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 5 inches of bituminous over 8 inches of aggregate base. POORLY GRADED SAND with SILT and GRAVEL, fine- to medium-grained, brown, moist. POORLY GRADED SAND with SILT, fine-grained, trace Gravel, brown, moist. END OF BORING. METHOD: Water not observed with 5 feet of hollow stem auger in the ground. Boring then backfilled. Power Auger Description of Materials BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. DATE: 10/7/14 SCALE: 1" = 4' BPF WL PAB-23 Tests or Notes LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:03 B Braun Intertec Corporation, Bloomington MN PAB-23 page 1 of 1

39 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV 1.1 SC 2.0 CL 3.0 SM SP- SM J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 5 1/2 inches of bituminous over 8 inches of aggregate base. CLAYEY SAND, brown, moist. LEAN CLAY with SAND, brown, wet. SILTY SAND, fine- to medium-grained, brown, moist. POORLY GRADED SAND with SILT, fine-grained, brown, moist. END OF BORING. METHOD: Water not observed with 5 feet of hollow stem auger in the ground. Water not observed to cave-in depth of 4 feet. Boring then backfilled. Power Auger Description of Materials BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. DATE: 10/7/14 SCALE: 1" = 4' BPF WL PAB-24 Tests or Notes LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:03 B Braun Intertec Corporation, Bloomington MN PAB-24 page 1 of 1

40 L O G O F B O R I N G (See Descriptive Terminology sheet for explanation of abbreviations) Braun Project B GEOTECHNICAL EVALUATION 2015 Pavement Improvement Program CSAH 21, CR 55, CR 65, CSAH 10/15 Washington County, Minnesota DRILLER: Depth feet 0.0 Symbol PAV 1.2 SC 5.0 J. Chermak (Soil-ASTM D2488 or D2487, Rock-USACE EM ) 6 inches of bituminous over 8 inches of aggregate base. CLAYEY SAND, fine- to medium-grained, trace Gravel, reddish brown, moist. END OF BORING. METHOD: Power Auger Description of Materials Water not observed with 5 feet of hollow stem auger in the ground. DATE: Water not observed to cave-in depth of 4 feet immediately after withdrawal of auger. BORING: LOCATION: CR 55 - CR 61 to CSAH 4. See attached sketch. 10/7/14 SCALE: 1" = 4' BPF WL PAB-25 Tests or Notes Boring then backfilled. LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2014\06463.GPJ BRAUN_V8_CURRENT.GDT 12/17/14 11:03 B Braun Intertec Corporation, Bloomington MN PAB-25 page 1 of 1

41 Descriptive Terminology of Soil Standard D Classification of Soils for Engineering Purposes (Unified Soil Classification System) Coarse-grained Soils more than 50% retained on No. 200 sieve Fine-grained Soils 50% or more passed the No. 200 sieve Gravels More than 50% of coarse fraction retained on No. 4 sieve Sands 50% or more of coarse fraction passes No. 4 sieve Silts and Clays Liquid limit less than 50 Silts and clays Liquid limit 50 or more Highly Organic Soils Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests a Clean Gravels 5% or less fines e Gravels with Fines More than 12% fines e Clean Sands 5% or less fines i Sands with Fines More than 12% i C u 4 and/or 1 C c 3 C Fines classify as ML or MH Fines classify as CL or CH Fines classify as ML or MH Fines classify as CL or CH Inorganic PI 7 and plots on or above A line j PI 4 or plots below A line j Organic Liquid limit - oven dried Liquid limit - not dried 0.75 Inorganic PI plots on or above A line PI plots below A line Organic Liquid limit - oven dried Liquid limit - not dried 0.75 Primarily organic matter, dark in color and organic odor a. Based on the material passing the 3-in (75mm) sieve. b. If field sample contained cobbles or boulders, or both, add with cobbles or boulders or both to group name. c. C u = D 60 / D 10 C c = (D 30 ) 2 D 10 x D 60 d. If soil contains 15% sand, add with sand to group name. e. 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 f. If fines classify as CL-ML, use dual symbol GC-GM or SC-SM. g. If fines are organic, add with organic fines to group name. h. If soil contains 15% gravel, add with gravel to group name. i. Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt SW-SC well-graded sand with clay SP-SM poorly graded sand with silt SP-SC poorly graded sand with clay j. If Atterberg limits plot in hatched area, soil is a CL-ML, silty clay. k. If soil contains 10 to 29% plus No. 200, add with sand or with gravel whichever is predominant. l. If soil contains 30% plus No. 200, predominantly sand, add sandy to group name. m. If soil contains 30% plus No. 200 predominantly gravel, add gravelly to group name. n. PI 4 and plots on or above A line. o. PI 4 or plots below A line. p. PI plots on or above A line. q. PI plots below A line. 60 C u 4 and 1 C c 3 C C u 6 and 1 C c 3 C C u 6 and/or 1 C C 3 C Soils Classification Group Symbol Group Name b GW Well-graded gravel d GP Poorly graded gravel d GM Silty gravel d f g GC Clayey gravel d f g SW Well-graded sand h SP SM Poorly graded sand h Silty sand f g h SC Clayey sand f g h CL Lean clay k l m ML Silt k l m OL Organic clay k l m n OL Organic silt k l m o CH Fat clay k l m MH Elastic silt k l m OH Organic clay k l m p OH Organic silt k l m q PT Peat 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, PI 4 or below A line Clay... No. 200, PI 4 and on or above A line Relative Density of Cohesionless Soils Very loose... 0 to 4 BPF Loose... 5 to 10 BPF Medium dense to 30 BPF Dense 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 to 16 BPF Very stiff to 30 BPF Hard... over 30 BPF Drilling Notes Standard penetration test borings were advanced by 3 1/4 or 6 1/4 ID hollow-stem augers unless noted otherwise, Jetting water was used to clean out auger prior to sampling only where indicated on logs. Standard penetration test borings are designated by the prefix ST (Split Tube). All samples were taken with the standard 2 OD split-tube sampler, except where noted. Power auger borings were advanced by 4 or 6 diameter continuousflight, solid-stem augers. Soil classifications and strata depths were inferred from disturbed samples augered to the surface and are, therefore, somewhat approximate. Power auger borings are designated by the prefix B. Plasticity Index (PI) U Line CH or OH CL or OL MH or OH CL - ML ML or OL Liquid Limit (LL) A Line Laboratory Tests DD Dry density, pcf OC Organic content, % WD Wet density, pcf S Percent of saturation, % MC Natural moisture content, % SG Specific gravity LL Liqiuid limit, % C Cohesion, psf PL Plastic limit, % Angle of internal friction PI Plasticity index, % qu Unconfined compressive strength, psf P200 % passing 200 sieve qp Pocket penetrometer strength, tsf Hand auger borings were advanced manually with a 1 1/2 or 3 1/4 diameter auger and were limited to the depth from which the auger could be manually withdrawn. Hand auger borings are indicated by the prefix H. 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 are reported in the following form: 2/12 for the second and third 6 increments, respectively. WH: WH indicates the sampler penetrated soil under weight of hammer and rods alone; driving not required. WR: WR indicates the sampler penetrated soil under weight of rods alone; hammer weight and driving not required. TW indicates thin-walled (undisturbed) tube sample. Note: All tests were run in general accordance with applicable ASTM standards. Rev. 7/07

42 Layer Depth (in) CR 55, GPR Results CR 61 to CSAH 7 0 Distance from CR 61 (ft) Bituminous

43 Layer Depth (in) CR 55, GPR Results CSAH 7 to CSAH 4 0 Distance from CSAH 7 (ft) Bituminous