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Geotechnical Engineering Report Subgrade Evaluation and Pavement Thickness Design Eagle Meadow Filing 2A SE of Eagle Meadow Drive and Golden Eagle Drive City of Dacono, Colorado February 26, 2016 Terracon Project No. 22165009

Prepared for: CivilArts 1500 Kansas Avenue, Suite 2-E Longmont, Colorado 80501

Prepared by: Terracon Consultants, Inc. 1242 Bramwood Place Longmont, Colorado 80501 TABLE OF CONTENTS

Page EXECUTIVE SUMMARY ...... i INTRODUCTION ...... 1 PROJECT INFORMATION ...... 1 Project Description ...... 1 Site Location and Description ...... 2 SUBSURFACE CONDITIONS ...... 3 Typical Profile ...... 3 Laboratory Testing ...... 3 Groundwater ...... 5 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ...... 5 Geotechnical Considerations ...... 5 Expansive Subgrade Soils ...... 5 Earthwork ...... 5 Site Preparation ...... 5 Fill Material Types ...... 6 Compaction Requirements ...... 6 Excavation and Utility Trench Construction ...... 7 Pavements ...... 8 Subgrade Preparation ...... 8 Design Considerations and Pavement Thickness ...... 10 Pavement Drainage ...... 12 Pavement Performance and Maintenance ...... 12 Additional Design and Construction Considerations ...... 13 Soluble Sulfates ...... 13 GENERAL COMMENTS ...... 14

APPENDIX A – FIELD EXPLORATION Exhibit A-1 Field Exploration Description Exhibit A-2 Boring Location Plan Exhibits A-3 to A-10 Boring Logs

APPENDIX B – LABORATORY TESTING Exhibit B-1 Laboratory Testing Exhibits B-2 to B-6 Swell-Consolidation Test Results Exhibits B-7 to B-8 Atterberg Limits/Percent Fines Test Results Exhibit B-9 Moisture-Density Relationship Test Results Exhibits B-10 to B-11 Remolded Swell Potential Test Results Exhibit B-12 R-value Test Results

TABLE OF CONTENTS – continued

APPENDIX C – SUPPORTING DOCUMENTS Exhibit C-1 General Notes Exhibit C-2 Unified Soil Classification Exhibit C-3 Rock Classification Exhibit C-4 Design Nomograph for Flexible Pavements Exhibit C-5 Pavement Design Calculations February 26, 2016

CivilArts 1500 Kansas Avenue, Suite 2-E Longmont, Colorado 80501

Attn: Mr. Frank Drexel, PLS P: [303] 682 1131 E: [email protected]

RE: Geotechnical Engineering Report Subgrade Evaluation and Pavement Thickness Design Eagle Meadow Filing 2A City of Dacono, Colorado Terracon Project Number: 22165009

Mr. Drexel:

Terracon Consultants, Inc. (Terracon) has completed the geotechnical and pavement engineering services for the project referenced above. This study was performed in general accordance with our proposal number P22165007 dated January 15, 2016. This report presents the findings of the subsurface exploration and provides geotechnical recommendations concerning subgrade preparation, general earthwork and pavement design and construction for the proposed project.

We appreciate the opportunity to be of service to you on this project. Materials testing and construction observation services are provided by Terracon as well. We would be pleased to discuss these services with you. If you have any questions concerning this report, or if we may be of further service, please contact us.

Sincerely, Terracon Consultants, Inc.

27741 2/26/2016

Eric S. Willis, P.E. Eric D. Bernhardt, P.E. Senior Project Manager/Engineer Geotechnical Department Manager

Copies to: Addressee (via email)

Terracon Consultants, Inc. 1242 Bramwood Place, Ste. 2 Longmont, Colorado 80501 P [303] 776 3921 F [303] 776 4041 www.terracon.com Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

EXECUTIVE SUMMARY

A subgrade evaluation and pavement thickness design has been performed for Eagle Meadow Filing 2A located southeast of the intersection of Eagle Meadow Drive and Golden Eagle Drive in the City of Dacono, Colorado. In accordance with City standards, eight (8) exploratory borings, designated P-1 through P-8, were performed to depths of about 8 to 10 feet below the existing ground surface.

Based on the information obtained from our subsurface exploration and laboratory testing program, the site appears suitable for the proposed construction from a geotechnical point of view provided certain precautions and design and construction recommendations presented in this report are followed. The following geotechnical conditions and considerations were identified:

 Subgrade soils encountered in the test borings consisted of about 4 to 8 feet, or more, of lean to fat clays with varying amounts of sand. Claystone and interbedded claystone/siltstone/sandstone bedrock was encountered below the overburden clays in most of the borings at depths of about 4 to 7 feet and these materials extended to the bottom of the borings. Soil classification and R-value testing indicate the subgrade soils offer poor pavement support.

 No groundwater was observed or measured in the borings at the time of the field exploration and when checked 3 days after completion of drilling to the depths explored.

 Five samples of the subgrade soil tested showed volumetric expansion ranging from about 7.5 to 10.1 percent under a confining pressure of 200 psf. Results of swell tests indicate the subgrade soils have high swell potential at their in-place moisture content and density. The Colorado Department of Transportation (CDOT) 2014 Pavement Design Manual characterizes these materials as having a high “Probable Swell Damage Risk”. Therefore, special pavement design and construction methods/precautions will be required for this project in order to mitigate pavement heave concerns. Heave mitigation techniques and recommendations are discussed in the report.

 Expansive subgrade soils are present on this site. The presence of expansive soils implies that pavements may heave and crack. The risks associated with swelling subgrade soils can be mitigated by careful design, construction and maintenance procedures; however, it should be recognized that these procedures will not eliminate risk. The owner should be aware and understand that pavements may be affected to some degree by the swelling soils on this site even if heave mitigation is performed.

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

 On-site soils typically appear suitable for use as engineered fill on the site provided they are placed and compacted as described in this report. Import materials (if needed) should be evaluated and approved by the geotechnical engineer prior to delivery to the site.

 Close monitoring of the construction operations and implementing drainage recommendations discussed herein will be critical in achieving the intended pavement performance. We therefore recommend that Terracon be retained to monitor this portion of the work.

This summary should be used in conjunction with the entire report for design purposes. It should be recognized that details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. The section titled GENERAL COMMENTS should be read for an understanding of the report limitations.

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GEOTECHNICAL ENGINEERING REPORT SUBGRADE EVALUATION AND PAVEMENT THICKNESS DESIGN EAGLE MEADOW FILING 2A CITY OF DACONO, COLORADO Terracon Project No. 22165009 February 26, 2016

INTRODUCTION

The purpose of these services is to provide information and geotechnical engineering recommendations relative to:

 Subgrade soil conditions  Subgrade preparation and earthwork  Groundwater conditions  Pavement thickness

The recommendations contained in this report are based on the results of field and laboratory testing, engineering analyses, experience with similar subgrade soils, traffic loading conditions and our understanding of the proposed project.

PROJECT INFORMATION

Project Description Item Description Site layout See Appendix A, Exhibit A-2, Boring Location Plan We understand the project will include construction and paving of the residential streets located within Filing 2A. Pavement construction will include approximately 1,900 Pavement construction lineal feet of public streets. Width for the proposed streets is expected to be on the order of about 25 to 30 feet. Concrete curb and gutter is not planned for this project.

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

Item Description Review of construction plans and other information provided indicates cuts and fills along the proposed streets are expected to be on the order of 0 to 3 feet. Swales will Grading be constructed on both sides of the streets for roadway drainage. As currently planned, side slopes for the swales will be constructed at 4H:1V (Horizontal to Vertical)

If project information varies from what is described above, we should be contacted as soon as possible to confirm and/or modify our recommendations accordingly.

Site Location and Description

Item Description The project site is located southeast of the intersection of Location Eagle Meadow Drive and Golden Eagle Drive in the City of Dacono, Colorado. The site is currently undeveloped land. Single-family homes are located to the north and west of the property, while open Existing improvements/existing site fields border the south, east and west sides. Oil/gas well- features head(s) and other collection equipment were noted to the west of the project site. Moderate growth of weeds and grasses. Barren ground at Current ground cover some locations. The ground surface in the project area is relatively uniform with an overall gentle slope down to the north-northwest. Existing topography Review of elevations provided indicates a maximum difference in elevation of roughly 8½ feet across the location of our test borings. The most prominent water feature in the vicinity of the project site is the Bull Canal located to the south and east. This feature is a concrete-lined channel. An earth-lined Water features ditch/channel was also noted to the west of the project area. No water was noted in these features at the time of our field exploration.

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

SUBSURFACE CONDITIONS

Typical Profile

Based on the results of the borings, subsurface conditions on the project site can be generalized as follows:

Approximate Consistency or General Engineering Depth to Bottom Material Encountered Relative Density/ Properties of Stratum Hardness About 6 inches in all borings with the Clay soil with vegetation and N/A N/A exception of boring root penetration P-1 High swell potential, poor Lean to fat clay with varying About 4 to 8 feet Stiff to hard pavement support amounts of sand characteristics Extended to Interbedded bottom of borings Weathered to Judged to have low to high claystone/siltstone/sandstone P-1, 2, 3, 5, 7 and medium hard swell potential and claystone bedrock 8

Subsurface conditions encountered at each boring location are indicated on the individual boring logs. Stratification boundaries on the boring logs represent the approximate location of changes in soil types; in-situ, the transition between materials may be gradual. Details for each of the borings can be found on the boring logs in Appendix A.

Laboratory Testing

The laboratory testing program was designed to provide index and/or engineering properties as well as subgrade support values for those soils which influence pavement design, construction and performance. The samples tested for this study have the following physical and/or engineering properties:

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

Silt or Classification Unconfined Sample Liquid Plasticity Expansion/Consolidation Boring Clay Compressive Depth Limit Index (%/Surcharge Load psf) No. Content Strength (ft.) (%) (%) USCS AASHTO (%) (psf) P-3 1 to 4 91 53 35 CH A-7-6(34) P-3 2 +8.7/200 P-3 4 23,120 P-4 1 to 4 93 49 30 CL A-7-6(30) P-4 2 +7.5/200 P-4 4 8580 P-5 1 to 4 77 46 27 CL A-7-6(20) P-6 1 to 4 91 51 34 CH A-7-6(33) P-6 2 +10.1/200 P-6 7 7,410 P-7 1 to 4 92 49 30 CL A-7-6(29) P-7 2 +10.0/200 P-8 1 to 4 92 50 30 CL/CH A-7-6(30)

A bulk sample of the clay subgrade soils from boring P-3 was subjected to a Hveem Stabilometer test (R-value) (AASHTO T 190) in the laboratory. An R-value of less than 5 was measured for this sample.

Volumetric swell tests indicate the subgrade soils typically have high swell potential at their in- place moisture content and density. The Colorado Department of Transportation (CDOT) 2014 Pavement Design Manual characterizes these materials as having a high “Probable Swell Damage Risk”.

A composite sample of the lean/fat clays was compiled from test borings P-3, 4, 6 and 7 in the laboratory. A moisture-density relationship curve (standard Proctor test) was performed on this sample. Samples were then remolded and compacted in the laboratory and subjected to swell testing to determine their behavior when loaded and wetted. This testing procedure was performed to evaluate the suitability of the on-site clays if re-used as moisture conditioned and compacted fill below pavements on the project. The following table presents the results of the testing. The remolded swell tests are presented in Appendix B.

Optimum Maximum Dry Remolded Swell Depth Moisture Soil Description Density (pcf) (%/Surcharge Load, psf) (ft.) Content (%) +2.4/200 1 Lean to fat clay 1 to 4 104.5 18.5 +1.8/200 2 Note: Samples remolded and compacted to approximately 95 percent of the material’s standard Proctor maximum dry density at about optimum moisture content1 and 2 percent above optimum2 as determined by ASTM D698.

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

Groundwater

No groundwater was observed or measured in the borings at the time of the field exploration and when checked 3 days after completion of drilling to the depths explored.

These observations represent short-term groundwater conditions at the time of and shortly after the field exploration, and may not be indicative of other times, or at other locations. Groundwater levels can fluctuate with varying seasonal and weather conditions, irrigation demands on or adjacent to the site and with fluctuations in nearby water features. Therefore, groundwater levels during construction or at other times in the future may be higher or lower than the levels indicated on the boring logs.

Fluctuations in groundwater levels can best be determined by implementation of a groundwater monitoring plan. Such a plan would include installation of groundwater monitoring wells, and periodic measurement of groundwater levels over a sufficient period of time.

RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION

Geotechnical Considerations

Based on geotechnical conditions encountered in our test borings, the site appears suitable for the proposed construction from a geotechnical point of view provided certain precautions and design and construction recommendations presented in this report are followed. Subgrade preparation, heave mitigation and other pavement design and construction recommendations are discussed in greater detail in the following sections.

Expansive Subgrade Soils Expansive subgrade soils are present on this site. The presence of expansive soils implies that pavements may heave and crack. The risks associated with swelling subgrade soils can be mitigated by careful design, construction and maintenance procedures; however, it should be recognized that these procedures will not eliminate risk. The owner should be aware and understand that pavements may be affected to some degree by the swelling soils on this site even if heave mitigation is performed.

Earthwork

Site Preparation The following presents recommendations for site preparation, excavation and placement of engineered fills on the project. Earthwork on the project should be observed and evaluated by Terracon. The evaluation of earthwork should include observation and testing of engineered fill,

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

subgrade preparation, pavement materials and other geotechnical conditions exposed during the construction of the project.

Site preparation should commence with removal of existing vegetation and loose, soft, or otherwise unsuitable material from the proposed construction areas. Stripped materials consisting of vegetation and organic materials should be wasted from the site, or used to re- vegetate landscaped areas or exposed slopes after completion of earthwork operations. Subgrade preparation and heave mitigation (ground modification) should be performed as described in section 4.3.1 Subgrade Preparation.

Exposed surfaces should be free of mounds and depressions that could prevent uniform compaction. Following completion of rough grading but prior to placement of new fill, the exposed ground should be scarified, moisture conditioned as needed and re-compacted. The subgrade should then be proof-rolled to help delineate weak or disturbed areas at or near the ground surface. Unsuitable areas should be improved by moisture adjustment and compaction or by undercutting and placement of suitable compacted fill.

Fill Material Types On-site soils free of vegetation, organic matter and other unsuitable materials or low volume change import materials approved by Terracon may be used as fill/backfill material on the site.

In general, imported materials (if needed) meeting the properties presented below should be acceptable for use on the site. However, imported soils should be evaluated and approved by the geotechnical engineer prior to delivery to the site.

Percent Finer by Weight Gradation/Property (ASTM C136) 3-inch 100 No. 4 Sieve 50 to 100 No. 200 Sieve 75 (max.)  Liquid Limit (LL) 40 (max.)  Plasticity Index (PI) 20 (max.)

Compaction Requirements Item Description  9 to 12-inches or less in loose thickness when heavy, self-propelled compaction equipment Fill Lift Thickness is used  4 to 6 inches in loose thickness when hand- guided equipment (i.e. jumping jack or plate

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

Item Description compactor) is used Compaction Engineered Fill, Subgrade At least 95% of the standard Proctor maximum Requirements1 and Utility Trenches dry density (ASTM D698) Moisture Content On-Site or Import Cohesive Within the range of optimum to 3 percent above Soils2 (CL, CH) optimum moisture content as determined by the standard Proctor test Moisture Content Import cohesive sands2 Within the range of 2 percent below to 2 percent (SC, SC-SM) above optimum as determined by the standard Proctor test

1. Engineered fill should be placed and compacted in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift. A construction disc or other suitable processing equipment will be needed to aid in achieving uniform moisture content throughout the fill. 2. The contractor should expect some moisture adjustment to the site soils or import fill (if used) prior to or during compaction operations.

Excavation and Utility Trench Construction We believe the soils encountered in our exploratory borings can be excavated with conventional excavation equipment. Groundwater seepage is not expected for excavations shallower than about 7 to 10 feet below current site grades. However, if seepage occurs or rain or snow-melt water accumulates in the excavation, it should be removed as soon as possible.

Trench excavations should be made with sufficient working space to permit construction including backfill placement and compaction. Trench backfill should consist of clean on-site soils or approved imported materials. Trench backfill should be placed and compacted as described above. It is strongly recommended that a representative of Terracon provide full-time observation and compaction testing of trench backfill within pavement areas.

The individual contractor(s) is responsible for designing and constructing stable, temporary excavations in order to maintain stability of excavation sides and bottom as well as any adjacent structures and foundations. Excavations should be sloped or shored in the interest of safety following local and federal regulations, including current Occupational Safety and Health Administration (OSHA) excavation and trench safety standards. As a safety measure, it is suggested vehicles and soil piles be kept to a minimum lateral distance from the crest of the slope equal to no less than the slope height. Exposed slope faces should be protected against the elements.

The soils to be penetrated by proposed excavations may vary significantly across the site. The preliminary soil classifications are based solely on the materials encountered in widely spaced

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

exploratory test borings. The contractor should verify that similar conditions exist throughout the proposed area of excavation. If different subsurface conditions are encountered at the time of construction, the actual conditions should be evaluated to determine any excavation modifications necessary to maintain safe conditions.

Pavements

Subgrade Preparation Expansive clay soils are present on this site and will be encountered at or near pavement subgrade elevations, depending upon final site grading. Pavements supported directly on or near expansive soils will likely heave and crack to some degree and create a maintenance problem and provide poor performance and serviceability and require periodic maintenance and repair.

To reduce movement and enhance performance, we recommend supporting pavements on a zone of low-volume change (LVC) fill consisting of properly moisture conditioned and compacted on-site soils or approved import materials. Based on our experience, a minimum 3-foot zone of LVC fill below pavements is considered appropriate. Depending upon final site grading, this will require over-excavation, moisture conditioning and re-compaction (ground modification) below site pavements. The fill should be placed and compacted as described in section 4.2.3 Compaction Requirements. It should be recognized that even if heave mitigation is performed some pavement distress and cracking should be anticipated.

In order to effectively reduce swell potential, the expansive clay materials will need to be properly processed and re-compacted at or above optimum moisture content. These types of materials, when compacted at higher moisture contents tend to “pump” and deflect when proof- rolled and can create a problem with subgrade stability. Consequently, we recommend a contingency be provided in the construction budget to chemically treat and stabilize the upper part of the subgrade in order to provide a stable surface for pavement construction.

Following over-excavation and recompaction (ground modification) below pavements as discussed above, we recommend the subgrade be proof-rolled shortly before paving operations to evaluate stability. Heavy construction equipment such as a loaded water truck or tandem axle dump truck is recommended for proof-rolling. For localized areas of unstable subgrade, we believe moisture conditioning and recompaction of the clay subgrade and/or over-excavation and placement of select granular fill could be used to correct these limited areas.

For wide-spread areas of unstable subgrades, soil stabilization by chemical treatment will likely be required and can increase the stability of the subgrade, add strength and stiffness to the subgrade, and improve the engineering properties of the soils. Our experience indicates lime treatment is typically more effective for stabilization of cohesive soils (clays), such as those found

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

on this site. Furthermore, the use of lime treatment can enhance pavement performance, extend pavement life and reduce maintenance requirements.

Sulfate concentrations measured in samples of the subgrade soils ranged from about 0.1 to 1.4 percent. The purpose of the tests was to assess the risk of increased swelling due to reaction to chemical stabilization. Sulfate concentrations above 0.2 percent can cause an adverse reaction between the sulfates and the stabilizing agent, resulting in heaving of the subgrade if lime stabilization is performed. Based on the test results, we believe there is a high risk of increased swelling due to sulfate reaction to chemical stabilizing agents at this site. We recommend chemical stabilizing agents be applied in a double treatment application to help reduce the risk of increased swelling due to potential ettringite formation.

We recommend the following general procedures for construction of chemically stabilized subgrade soils.

 The pavement subgrade should be shaped to final grade.

 Hydrated or quick lime should meet the requirements of ASTM C207, Type N and be mixed as outlined in ASTM C977.

 Lime treatment should be to a minimum depth of 8 inches. Hydrated lime and subgrade soils should be applied, mixed and compacted in general accordance with CDOT specifications. Based on our experience, a total of 5 to 7 percent lime should be uniformly mixed into the subgrade.

 Because of high sulfate concentrations in the subgrade soils on this site, we recommend that ½ of the total lime be used during the initial phase of construction and the lime slurry/soil mixture be allowed to mellow for a period of 5 to 7 days. The mellowing time needed will depend on weather conditions, continuous moistening of the lime-soil mixture, protection measures to promote ettringite crystal formation, and soil properties. Terracon can assist with determining the appropriate mellowing time as the process approaches 5 days.

 The partially treated subgrade should then be remixed in order to mechanically break down any ettringite formation that has occurred. Following this process, the remaining ½ of the total lime slurry can then be mixed into the subgrade and should be allowed to mellow for at least an additional 48 hours.

 The lime and soil should be moisture conditioned to within 2 percent of optimum moisture content and compacted to at least 95 percent of the mixture’s maximum dry unit weight as determined by ASTM D698. The subgrade should then be re-shaped to

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

final grade. The treated subgrade should be allowed to cure prior to placing aggregate base course.

 The subgrade should be sealed with a pneumatic-tire roller that is sufficiently light in weight so as to not cause hairline cracking of the treated subgrade.

 The surface of the treated subgrade/stabilized area should be kept moist during the cure periods by periodic light sprinkling, if needed.

Strength gains of treated subgrade will be slower during cooler weather periods, particularly if the temperature drops below 40 degrees Fahrenheit. Construction traffic on the treated subgrade prior to placement of the aggregate base course and pavement construction should be limited and the subgrade should be protected from freezing or drying until paving. Covering the subgrade or other protective measures may be required.

Placement and compaction of engineered fill, subgrade soils, chemically treated subgrade, base course and other pavement materials should be observed and tested by a representative of Terracon to verify the specified moisture and/or compaction requirements have been achieved.

Design Considerations and Pavement Thickness Moisture conditioned and recompacted lean to fat clay soils will support pavements on this site. Laboratory testing indicates the subgrade materials classify as A-7-6 soils according to the American Association of State Highway and Transportation Officials (AASHTO) classification system. AASHTO group indices of these soils ranged from 20 to 34. These subgrade materials have "CL" and "CH" classifications in accordance with the Unified Soil Classification System (USCS) methods. Based on physical properties and the R-value test, we judge the subgrade soils at the site to offer poor pavement support.

Thickness design of pavements for the project was based on the procedures outlined in the City of Dacono, Colorado Standards & Specifications for Design and Construction of Public Improvements (September 2010, Revised January 2015) using the appropriate flexible pavement nomograph (Table 5.6) to determine the design structural number (SN). Design parameters or other data used for determining pavement thickness for this project are summarized in the following table.

Pavement Design Parameter/Data Value/Designation Roadway Classification Local Residential 18-kip Equivalent Daily Load Application (EDLA) 10 Design Period 20 years R-value (Determined in Laboratory) Less than 5

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

Pavement Design Parameter/Data Value/Designation Serviceability Index (SI) 2.0 Design Structural Number (SN) 3.1

Pavement Section Thickness (inches) Aggregate Asphalt Over-Excavation/ Base Traffic Area Alternative Concrete Course Ground Modification (AC) 1 (ABC) 2 Depth Local Residential Streets AC + ABC 5 9 36 1. Superpave asphalt mixtures with aggregates meeting CDOT Grading SG, S or SX specification is recommended for asphalt concrete (AC). Asphalt should be placed in maximum 2½ to 3-inch lifts (4-inch max for SG) and compacted to a density of 92 to 96 percent of the maximum theoretical density, determined in general accordance with ASTM D2041 (Colorado Procedure 51). 2. Aggregate base course (ABC) should consist of a blend of sand and gravel which meets strict specifications for quality and gradation and should have an R-value of at least 77. Use of materials meeting Colorado Department of Transportation (CDOT) Class 5 or 6 specifications is recommended. ABC should be placed in maximum 6-inch lifts and compacted to at least 95 percent of the modified Proctor maximum dry density (ASTM D1557/AASHTO T 180). 3. The City of Dacono, Colorado Standards & Specifications for Design and Construction of Public Improvements (September 2010, Revised January 2015) do not allow the use of full-depth asphalt pavement sections.

If lime treatment of the upper part of the subgrade (LTS) is required to provide a stable surface for pavement construction and/or desired to enhance long-term pavement performance, we recommend the following pavement thickness.

Pavement Section Thickness (inches) Over- Aggregate Lime Asphalt Excavation/ Base Treated Traffic Area Alternative Concrete Course Subgrade Ground (AC) (ABC) (LTS) 1 Modification Depth Local Residential AC + ABC + LTS 4 6 8 28 Streets 1. Lime treated subgrade (LTS) should have a minimum 7-day unconfined compressive strength of at least 125 psi to receive full credit for the treated subgrade in pavement section calculations. If the minimum compressive strength cannot be achieved in the field, modification to pavement component thickness (i.e. increasing AC or ABC thickness) will be required. Based on supplemental laboratory mix design preparation prior to construction and/or compressive strength specimens prepared during construction.

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

The flexible pavement design nomograph along with pavement thickness design calculations are included in Appendix C.

Design parameters such as serviceability, EDLA, actual strength coefficients and other factors may vary with specific project requirements. Variation of these parameters may change the thickness of the pavement sections presented. Terracon is prepared to discuss the details of these parameters and their effects on pavement design and reevaluate pavement thickness as appropriate.

Pavement Drainage Pavements should be crowned and sloped to provide rapid drainage of surface water. Adequate slopes and swales adjacent to the roadway should be provided and maintained to promote surface water drainage away from the pavement system. Water allowed to pond on or adjacent to the pavements could saturate the subgrade and contribute to subgrade heave and premature pavement deterioration. Collection and diversion of surface drainage away from paved areas is critical to satisfactory performance of pavements.

Pavement Performance and Maintenance Our experience indicates longitudinal cracking is common for asphalt pavements. The cracking normally occurs parallel to the interface between asphalt and concrete features such as curbs, gutters or drain pans and/or several feet in from pavement edges. The mechanism for this cracking is not fully understood, but seems to be most prevalent for expansive and/or cohesive subgrade soils. Distress of this type is likely to occur even if the subgrade has been properly prepared and the asphalt has been compacted properly.

Since the clay soils on the site have shrink/swell characteristics, pavements could crack in the future primarily because of expansion of the soils/bedrock when subjected to an increase in moisture content even after heave mitigation is performed. The cracking, while not desirable, does not normally constitute structural failure of the pavement, provided timely maintenance, such as crack sealing and other surface treatments is performed.

Pavement performance is affected by its surroundings. In addition to providing preventive maintenance, the civil engineer and other members of the design team should consider the following recommendations in the design and layout of pavements:

 Site grading at a minimum 2 percent grade onto or away from the pavements;  Install pavement drainage surrounding areas anticipated for frequent wetting;  Install joint sealant and seal cracks immediately;  Use low water-demand plantings and drip irrigation for landscaped areas (if any)  Seal all landscaped areas in, or adjacent to pavements to reduce moisture migration to subgrade soils;

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Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

 Compaction of utility trenches for landscaped areas to the same criteria as the pavement subgrade

The pavement sections provided in this report represent minimum recommended thickness and, as such, periodic maintenance should be anticipated. Therefore, preventive maintenance should be planned and provided for through an on-going pavement management program. Preventive maintenance activities are intended to slow the rate of pavement deterioration.

Preventive maintenance consists of both localized maintenance (e.g. crack and joint sealing and patching) and global maintenance (e.g. surface sealing). Preventive maintenance is usually the first priority when implementing a planned pavement maintenance program. Prior to implementing maintenance, additional engineering observation is recommended to determine the type and extent of preventive maintenance. Even with periodic maintenance, some movements and related cracking may still occur and repairs may be required.

Additional Design and Construction Considerations

Soluble Sulfates Samples of the subgrade soils were tested for soluble sulfate concentrations. The purpose of the tests was to assess the risk of increased swelling due to reaction to chemical stabilization. The sulfate concentrations measured in the samples ranged from about 0.1 to 1.4 percent. Most of the samples tested showed sulfate concentrations in excess of 0.2 percent. Sulfate concentrations above 0.2 percent can cause an adverse reaction between the sulfates and the stabilizing agent, resulting in heaving of the subgrade if lime or fly ash stabilization is performed. Based on the test results, we believe there is a high risk of increased swelling due to sulfate reaction to chemical stabilizing agents at this site. We recommend chemical stabilizing agents be applied in a double treatment application to help reduce the risk of increased swelling due to potential ettringite formation. General guidelines for double treatment application are presented in the Subgrade Preparation section of this report.

Sulfate concentrations in the range of 0.2 to less than 2 percent indicate Class 2 exposure to sulfate attack for concrete in contact with the subsoils, according to the American Concrete Institute (ACI) Guide to Durable Concrete.

For Class 2 sulfate exposure, ACI recommends the use of Type V cement (or equivalent) and a maximum water-cement ratio of 0.45. As an alternative, ACI allows the use of cement that conforms to ASTM C150 Type II requirements, if it meets the Type V performance requirements (ASTM C452) of ASTM C150 Table 4. ACI 201 also allows a blend of any type of portland cement and fly ash with an expansion of less than 0.05 percent at 6 months when tested in accordance with ASTM C1012.

Responsive ■ Resourceful ■ Reliable 13

Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

GENERAL COMMENTS

Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide testing and observation during excavation, backfilling, subgrade preparation and pavement construction phases of the project.

The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, or due to the modifying effects of construction, weather or time. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided.

The scope of services for this project does not include either specifically or by implication any environmental assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken.

This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing.

Responsive ■ Resourceful ■ Reliable 14

APPENDIX A

FIELD EXPLORATION

Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

Field Exploration Description Eight (8) test borings were drilled at the site on January 26, 2016. The borings were drilled and sampled to depths of about 8 to 10 feet at the approximate locations shown on the Boring Location Plan, Exhibit A-2. All borings were drilled along the alignment of the proposed street construction. Borings were advanced with a CME-45 truck-mounted drilling rig, utilizing 6-inch diameter solid stem auger.

The boring locations and ground surface elevations were surveyed in the field by CivilArts. The latitude and longitude coordinates shown on the boring logs were obtained by locating the borings on Google Earth and recording the values. The accuracy of these coordinates should only be assumed to the level implied by the method used.

A geotechnical engineer recorded lithologic logs of each boring during the drilling operations. At selected intervals, samples of the subsurface materials were taken by means of driving a 2.5-inch O.D. California barrel sampler. Bulk samples were also obtained from the test borings. Penetration resistance measurements were obtained by driving the California barrel into the subsurface materials with a 140-pound hammer falling 30 inches. The penetration resistance value, when properly interpreted, is a useful index in estimating the consistency, relative density, or hardness of the materials encountered.

Groundwater levels were recorded in each boring at the time of site exploration and 3 days after completion of drilling. After the groundwater levels were checked, the borings were backfilled with on-site soils (auger cuttings). Some settlement of the backfill may occur over time and should be repaired as soon as possible.

A CME automatic SPT hammer was used to advance the California barrel sampler in the borings performed on this site. A greater efficiency is typically achieved with the automatic hammer compared to the conventional safety hammer operated with a cathead and rope. Published correlations between penetration values and soil properties are based on the lower efficiency cathead and rope method. This higher efficiency affects the penetration resistance blow count value by increasing the penetration per hammer blow over what would be obtained using the cathead and rope method. The effect of the automatic hammer’s efficiency has been considered in the interpretation and analysis of the subsurface information for this report.

The penetration test provides a reasonable indication of the in-place density of sandy type materials, but only provides an indication of the relative stiffness of cohesive materials since the blow count in these soils may be affected by the soils moisture content.

Exhibit A-1 EAGLE MEADOW DRIVE

P-1 JAY COURT HAWK JAY

WELD COUNTY ROAD 10

EAGLE MEADOW DR.

P-2 INTERSTATE 25 YORK STREET YORK

P-5 P-3 PROJECT SITE P-6 P-4

P-7 VICINITY MAP

N.T.S STREET

P-8 YORK

APPROX. GRAPHIC SCALE

0’ 125’ 250’

LEGEND:

APPROXIMATE LOCATION OF TEST BORING DRILLED ON JANUARY 26, 2016 Project Manager: Project No. ESW 22165009 BORING LOCATION PLAN EXHIBIT Drawn by: Scale: ESW/GMM 1” = 250’ +/- CIVILARTS Checked by: File Name: EDB SUBGRADE EVALUATION AND PAVEMENT THICKNESS DESIGN 22165009 BLP 1242 Bramwood Place Longmont, Colorado 80501 DIAGRAM IS FOR GENERAL LOCATION ONLY, AND EAGLE MEADOW FILING 2A A-2 Approved by: Date: PH. (303) 776-3921 FAX. (303) 776-4041 IS NOT INTENDED FOR CONSTRUCTION PURPOSES CITY OF DACONO, COLORADO ESW 1/22/2016 BORING LOG NO. P-1 Page 1 of 1 PROJECT: Subgrade Evaluation & Pavement CLIENT: CivilArts Thickness Design Longmont, Colorado SITE: Eagle Meadow Filing 2A Dacono, Colorado ATTERBERG LOCATION See Exhibit A-2 LIMITS

LL-PL-PI WATER RESULTS DRY UNIT DEPTH (Ft.)

Surface Elev.: 5115.4 (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG UNCONFINED CONTENT (%) LOAD, (% / psf) WATER LEVEL COMPRESSIVE STRENGTH (psf) SAMPLE TYPE SAMPLE OBSERVATIONS PERCENT FINES DEPTH ELEVATION (Ft.) SWELL-CONSOL / LEAN CLAY (CL), trace SAND, brown with beige, stiff to hard

13/12" 10560 15 108

4.0 5111.5 CLAYSTONE/SILTSTONE/SANDSTONE, interbedded, tan, yellow brown, olive, rust, weathered to 22/12" 12 115 firm 5

34/12" 9 118 8.0 5107.5 Boring Terminated at 8 Feet

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

Advancement Method: Notes: 6-inch diameter solid flight auger See Appendix B for description of laboratory procedures and additional data (if any). Abandonment Method: See Appendix C for explanation of symbols and Boring backfilled with soil cuttings after groundwater check on abbreviations. 1/29/2016

WATER LEVEL OBSERVATIONS Boring Started: 1/26/2016 Boring Completed: 1/26/2016 None encountered after completion of drilling Drill Rig: CME-45 Driller: ODELL Dry at 7 feet when checked on 1/29/2016 1242 Bramwood Place Longmont, Colorado Project No.: 22165009 Exhibit: A-3 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2015.GDT 2/23/16 TERRACON2015.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE WELL LOG-NO SMART GEO REPORT. ORIGINAL FROM IF SEPARATED VALID NOT IS LOG THISBORING BORING LOG NO. P-2 Page 1 of 1 PROJECT: Subgrade Evaluation & Pavement CLIENT: CivilArts Thickness Design Longmont, Colorado SITE: Eagle Meadow Filing 2A Dacono, Colorado ATTERBERG LOCATION See Exhibit A-2 LIMITS

LL-PL-PI WATER RESULTS DRY UNIT DEPTH (Ft.)

Surface Elev.: 5118.3 (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG UNCONFINED CONTENT (%) LOAD, (% / psf) WATER LEVEL COMPRESSIVE STRENGTH (psf) SAMPLE TYPE SAMPLE OBSERVATIONS PERCENT FINES DEPTH ELEVATION (Ft.) SWELL-CONSOL / 0.5 VEGETATIVE SOIL LAYER, CLAY soil with vegetation 5118 and root penetration LEAN CLAY (CL), trace SAND, brown with beige, stiff, calcareous

16/12" +8.0/200 13 113 44-18-26 89

12/12" 14 109 5

7.0 5111.5 CLAYSTONE/SILTSTONE/SANDSTONE, interbedded, olive-tan, yellow brown, rust, medium hard

41/12" 10 118 10.0 5108.5 10 Boring Terminated at 10 Feet

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

WATER LEVEL OBSERVATIONS Boring Started: 1/26/2016 Boring Completed: 1/26/2016 None encountered after completion of drilling Drill Rig: CME-45 Driller: ODELL Dry at 9 feet when checked on 1/29/2016 1242 Bramwood Place Longmont, Colorado Project No.: 22165009 Exhibit: A-4 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2015.GDT 2/23/16 TERRACON2015.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE WELL LOG-NO SMART GEO REPORT. ORIGINAL FROM IF SEPARATED VALID NOT IS LOG THISBORING BORING LOG NO. P-3 Page 1 of 1 PROJECT: Subgrade Evaluation & Pavement CLIENT: CivilArts Thickness Design Longmont, Colorado SITE: Eagle Meadow Filing 2A Dacono, Colorado ATTERBERG LOCATION See Exhibit A-2 LIMITS

LL-PL-PI WATER RESULTS DRY UNIT DEPTH (Ft.)

Surface Elev.: 5119.2 (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG UNCONFINED CONTENT (%) LOAD, (% / psf) WATER LEVEL COMPRESSIVE STRENGTH (psf) SAMPLE TYPE SAMPLE OBSERVATIONS PERCENT FINES DEPTH ELEVATION (Ft.) SWELL-CONSOL / 0.5 VEGETATIVE SOIL LAYER, CLAY soil with vegetation 5118.5 and root penetration FAT CLAY (CH), trace SAND, dark brown to brown with beige, very stiff to hard, varies to LEAN CLAY (CL)

34/12" +8.7/200 12 125 53-18-35 91

27/12" 23120 15 115 5

6.0 5113 CLAYSTONE, grey, rust, weathered

17/12" 18 110 8.0 5111 Boring Terminated at 8 Feet

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

WATER LEVEL OBSERVATIONS Boring Started: 1/26/2016 Boring Completed: 1/26/2016 None encountered after completion of drilling Drill Rig: CME-45 Driller: ODELL Dry at 7 feet when checked on 1/29/2016 1242 Bramwood Place Longmont, Colorado Project No.: 22165009 Exhibit: A-5 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2015.GDT 2/23/16 TERRACON2015.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE WELL LOG-NO SMART GEO REPORT. ORIGINAL FROM IF SEPARATED VALID NOT IS LOG THISBORING BORING LOG NO. P-4 Page 1 of 1 PROJECT: Subgrade Evaluation & Pavement CLIENT: CivilArts Thickness Design Longmont, Colorado SITE: Eagle Meadow Filing 2A Dacono, Colorado ATTERBERG LOCATION See Exhibit A-2 LIMITS

LL-PL-PI WATER RESULTS DRY UNIT DEPTH (Ft.)

Surface Elev.: 5122.1 (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG UNCONFINED CONTENT (%) LOAD, (% / psf) WATER LEVEL COMPRESSIVE STRENGTH (psf) SAMPLE TYPE SAMPLE OBSERVATIONS PERCENT FINES DEPTH ELEVATION (Ft.) SWELL-CONSOL / 0.5 VEGETATIVE SOIL LAYER, CLAY soil with vegetation 5121.5 and root penetration LEAN CLAY (CL), trace SAND, brown with beige, very stiff to hard

26/12" +7.5/200 16 116 49-19-30 93

4.5 5117.5 19/12" 8580 18 110 LEAN/FAT CLAY to Highly Weathered CLAYSTONE (CL/CH), olive, grey, rust, stiff to hard 5

11/12" 27 96 8.0 5114 Boring Terminated at 8 Feet

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

WATER LEVEL OBSERVATIONS Boring Started: 1/26/2016 Boring Completed: 1/26/2016 None encountered after completion of drilling Drill Rig: CME-45 Driller: ODELL Dry at 7 feet when checked on 1/29/2016 1242 Bramwood Place Longmont, Colorado Project No.: 22165009 Exhibit: A-6 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2015.GDT 2/23/16 TERRACON2015.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE WELL LOG-NO SMART GEO REPORT. ORIGINAL FROM IF SEPARATED VALID NOT IS LOG THISBORING BORING LOG NO. P-5 Page 1 of 1 PROJECT: Subgrade Evaluation & Pavement CLIENT: CivilArts Thickness Design Longmont, Colorado SITE: Eagle Meadow Filing 2A Dacono, Colorado ATTERBERG LOCATION See Exhibit A-2 LIMITS

LL-PL-PI WATER RESULTS DRY UNIT DEPTH (Ft.)

Surface Elev.: 5117.7 (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG UNCONFINED CONTENT (%) LOAD, (% / psf) WATER LEVEL COMPRESSIVE STRENGTH (psf) SAMPLE TYPE SAMPLE OBSERVATIONS PERCENT FINES DEPTH ELEVATION (Ft.) SWELL-CONSOL / 0.5 VEGETATIVE SOIL LAYER, CLAY soil with vegetation 5117 and root penetration LEAN CLAY with SAND (CL), brown with tan/beige, very stiff

22/12" 14 113 46-19-27 77

4.0 5113.5 CLAYSTONE/SILTSTONE/SANDSTONE, interbedded, olive-tan, yellow brown, rust, grey, firm to 26/12" 13 medium hard, iron concretions in upper part 5

45/12" 10 123 8.0 5109.5 Boring Terminated at 8 Feet

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

WATER LEVEL OBSERVATIONS Boring Started: 1/26/2016 Boring Completed: 1/26/2016 None encountered after completion of drilling Drill Rig: CME-45 Driller: ODELL Dry at 7 feet when checked on 1/29/2016 1242 Bramwood Place Longmont, Colorado Project No.: 22165009 Exhibit: A-7 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2015.GDT 2/23/16 TERRACON2015.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE WELL LOG-NO SMART GEO REPORT. ORIGINAL FROM IF SEPARATED VALID NOT IS LOG THISBORING BORING LOG NO. P-6 Page 1 of 1 PROJECT: Subgrade Evaluation & Pavement CLIENT: CivilArts Thickness Design Longmont, Colorado SITE: Eagle Meadow Filing 2A Dacono, Colorado ATTERBERG LOCATION See Exhibit A-2 LIMITS

LL-PL-PI WATER RESULTS DRY UNIT DEPTH (Ft.)

Surface Elev.: 5118.9 (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG UNCONFINED CONTENT (%) LOAD, (% / psf) WATER LEVEL COMPRESSIVE STRENGTH (psf) SAMPLE TYPE SAMPLE OBSERVATIONS PERCENT FINES DEPTH ELEVATION (Ft.) SWELL-CONSOL / 0.5 VEGETATIVE SOIL LAYER, CLAY soil with vegetation 5118.5 and root penetration FAT CLAY (CH), trace SAND, brown with beige to olive brown with grey, very stiff to stiff, varies to LEAN CLAY (CL) 31/12" +10.1/200 12 121 51-17-34 91

14/12" 19 109 5

16/12" 7410 19 109 8.0 5111 Boring Terminated at 8 Feet

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

WATER LEVEL OBSERVATIONS Boring Started: 1/26/2016 Boring Completed: 1/26/2016 None encountered after completion of drilling Drill Rig: CME-45 Driller: ODELL Dry at 7 feet when checked on 1/29/2016 1242 Bramwood Place Longmont, Colorado Project No.: 22165009 Exhibit: A-8 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2015.GDT 2/23/16 TERRACON2015.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE WELL LOG-NO SMART GEO REPORT. ORIGINAL FROM IF SEPARATED VALID NOT IS LOG THISBORING BORING LOG NO. P-7 Page 1 of 1 PROJECT: Subgrade Evaluation & Pavement CLIENT: CivilArts Thickness Design Longmont, Colorado SITE: Eagle Meadow Filing 2A Dacono, Colorado ATTERBERG LOCATION See Exhibit A-2 LIMITS

LL-PL-PI WATER RESULTS DRY UNIT DEPTH (Ft.)

Surface Elev.: 5121.2 (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG UNCONFINED CONTENT (%) LOAD, (% / psf) WATER LEVEL COMPRESSIVE STRENGTH (psf) SAMPLE TYPE SAMPLE OBSERVATIONS PERCENT FINES DEPTH ELEVATION (Ft.) SWELL-CONSOL / 0.5 VEGETATIVE SOIL LAYER, CLAY soil with vegetation 5120.5 and root penetration LEAN CLAY (CL), trace SAND, brown to dark brown with tan/beige, hard to stiff

38/12" +10.0/200 14 119 49-19-30 92

16/12" 21 105 5

6.0 5115 CLAYSTONE, grey, light grey, rust, weathered

19/12" 21 105 8.0 5113 Boring Terminated at 8 Feet

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

WATER LEVEL OBSERVATIONS Boring Started: 1/26/2016 Boring Completed: 1/26/2016 None encountered after completion of drilling Drill Rig: CME-45 Driller: ODELL Dry at 7 feet when checked on 1/29/2016 1242 Bramwood Place Longmont, Colorado Project No.: 22165009 Exhibit: A-9 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2015.GDT 2/23/16 TERRACON2015.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE WELL LOG-NO SMART GEO REPORT. ORIGINAL FROM IF SEPARATED VALID NOT IS LOG THISBORING BORING LOG NO. P-8 Page 1 of 1 PROJECT: Subgrade Evaluation & Pavement CLIENT: CivilArts Thickness Design Longmont, Colorado SITE: Eagle Meadow Filing 2A Dacono, Colorado ATTERBERG LOCATION See Exhibit A-2 LIMITS

LL-PL-PI WATER RESULTS DRY UNIT DEPTH (Ft.)

Surface Elev.: 5123.9 (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG UNCONFINED CONTENT (%) LOAD, (% / psf) WATER LEVEL COMPRESSIVE STRENGTH (psf) SAMPLE TYPE SAMPLE OBSERVATIONS PERCENT FINES DEPTH ELEVATION (Ft.) SWELL-CONSOL / 0.5 VEGETATIVE SOIL LAYER, CLAY soil with vegetation 5123.5 and root penetration LEAN to FAT CLAY (CL/CH), trace SAND, brown with tan/beige, very stiff, calcareous

24/12" 20 106 50-20-30 92

4.5 5119.5 18/12" 22 103 CLAYSTONE, olive-grey, dark grey, rust, weathered to firm 5

29/12" 18 111 10.0 5114 10 Boring Terminated at 10 Feet

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

WATER LEVEL OBSERVATIONS Boring Started: 1/26/2016 Boring Completed: 1/26/2016 None encountered after completion of drilling Drill Rig: CME-45 Driller: ODELL Dry at 9 feet when checked on 1/29/2016 1242 Bramwood Place Longmont, Colorado Project No.: 22165009 Exhibit: A-10 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2015.GDT 2/23/16 TERRACON2015.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE WELL LOG-NO SMART GEO REPORT. ORIGINAL FROM IF SEPARATED VALID NOT IS LOG THISBORING

APPENDIX B

LABORATORY TESTING

Geotechnical Engineering Report Subgrade Evaluation & Pavement Thickness Design Eagle Meadow Filing 2A ■ City of Dacono, Colorado February 26, 2016 ■ Terracon Project No. 22165009

Laboratory Testing Samples retrieved during the field exploration were returned to the laboratory for observation by the project geotechnical engineer and were visually classified in general accordance with the Unified Soil Classification System described in Appendix C. Samples of bedrock were classified in accordance with the general notes for Rock Classification.

After sample review by the project engineer, an applicable laboratory testing program was formulated to determine engineering properties of the subsurface materials. Following completion of the laboratory testing, the field and visual descriptions were confirmed or modified as necessary, and Logs of Borings were prepared. These logs are presented in Appendix A.

Selected samples were tested for the following physical and/or engineering properties:

 Water Content  Percent Fines  Dry Unit Weight  Moisture-Density Relationship  Unconfined Compressive Strength  Remolded Swell Potential  Swell-Consolidation Potential  R-value  Atterberg Limits  Water Soluble Sulfate Content

Laboratory test results are indicated on the boring logs included in Appendix A and presented in depth in Appendix B. The test results were used for the geotechnical engineering analyses and the development of pavement thickness and subgrade preparation/earthwork recommendations. Laboratory tests were performed in general accordance with applicable local standards or other accepted standards.

Descriptive classifications of the soils indicated on the boring logs are in accordance with the enclosed General Notes and the Unified Soil Classification System. Also shown are estimated Unified Soil Classification Symbols. A brief description of this classification system is attached to this report. Classification was by visual-manual procedures. Selected samples were further classified using the results of Atterberg limit testing. The Atterberg limit test results are also provided in Appendix B.

Exhibit B-1 SWELL CONSOLIDATION TEST

2 AXIAL STRAIN, % 0

-2

-4

-6

-8

-10 100 1,000 10,000 105

PRESSURE, psf

Specimen Identification Classification , pcf WC, % P-2 2 - 3 ft LEAN CLAY (CL) 113 13

NOTES: Sample exhibited 8.0 percent expansion under an applied pressure of 200 psf.

2 AXIAL STRAIN, % 0

-2

-4

-6

-8

-10 100 1,000 10,000 105

PRESSURE, psf

Specimen Identification Classification , pcf WC, % P-3 2 - 3 ft FAT CLAY (CH) 125 12

NOTES: Sample exhibited 8.7 percent expansion under an applied pressure of 200 psf.

2 AXIAL STRAIN, % 0

-2

-4

-6

-8

-10 100 1,000 10,000 105

PRESSURE, psf

Specimen Identification Classification , pcf WC, % P-4 2 - 3 ft LEAN CLAY (CL) 116 16

NOTES: Sample exhibited 7.5 percent expansion under an applied pressure of 200 psf.

2 AXIAL STRAIN, % 0

-2

-4

-6

-8

-10 100 1,000 10,000 105

PRESSURE, psf

Specimen Identification Classification , pcf WC, % P-6 2 - 3 ft FAT CLAY (CH) 121 12

NOTES: Sample exhibited 10.1 percent expansion under an applied pressure of 200 psf.

2 AXIAL STRAIN, % 0

-2

-4

-6

-8

-10 100 1,000 10,000 105

PRESSURE, psf

Specimen Identification Classification , pcf WC, % P-7 2 - 3 ft LEAN CLAY (CL) 119 14

NOTES: Sample exhibited 10.0 percent expansion under an applied pressure of 200 psf.

PROJECT: Subgrade Evaluation & Pavement Thickness PROJECT NUMBER: 22165009 Design SITE: Eagle Meadow Filing 2A CLIENT: CivilArts Dacono, Colorado Longmont, Colorado 1242 Bramwood Place Longmont, Colorado EXHIBIT: B-6 LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. TC_CONSOL_STRAIN-USCS-NO ASTM 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2012.GDT 2/9/16 TERRACON2012.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE ASTM TC_CONSOL_STRAIN-USCS-NO REPORT. ORIGINAL FROM IF SEPARATED VALID NOT ARE TESTS LABORATORY GRAIN SIZE DISTRIBUTION ASTM D422 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS HYDROMETER 4 2 1 1/2 3 6 10 16 30 50 100 200 6 3 1.5 3/4 3/8 4 8 14 20 40 60 140 100

40 PERCENT FINER BY WEIGHT 35

0 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS GRAVEL SAND COBBLES SILT OR CLAY coarse fine coarse medium fine

Boring ID Depth USCS Classification AASHTO Classification LL PL PI Cc Cu P-2 1 - 4 LEAN CLAY (CL) A-7-6(24) 44 18 26

P-3 1 - 4 FAT CLAY (CH) A-7-6(34) 53 18 35

P-4 1 - 4 LEAN CLAY (CL) A-7-6(30) 49 19 30

P-5 1 - 4 LEAN CLAY with SAND (CL) A-7-6(20) 46 19 27

Boring ID Depth D100 D60 D30 D10 %Gravel %Sand %Silt %Clay P-2 1 - 4 0.075 0.0 0.0 88.7

P-3 1 - 4 0.075 0.0 0.0 91.4

P-4 1 - 4 0.075 0.0 0.0 93.3

P-5 1 - 4 0.075 0.0 0.0 77.2

PROJECT: Subgrade Evaluation & Pavement Thickness Design PROJECT NUMBER: 22165009

SITE: Eagle Meadow Filing 2A CLIENT: CivilArts Dacono, Colorado Longmont, Colorado 1242 Bramwood Place Longmont, Colorado EXHIBIT: B-7 LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS & AASHTO COMBINED 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2012.GDT 2/9/16 TERRACON2012.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE COMBINED AASHTO & USCS SIZE: GRAIN REPORT. ORIGINAL FROM IF SEPARATED VALID NOT ARE TESTS LABORATORY GRAIN SIZE DISTRIBUTION ASTM D422 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS HYDROMETER 4 2 1 1/2 3 6 10 16 30 50 100 200 6 3 1.5 3/4 3/8 4 8 14 20 40 60 140 100

40 PERCENT FINER BY WEIGHT 35

0 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS GRAVEL SAND COBBLES SILT OR CLAY coarse fine coarse medium fine

Boring ID Depth USCS Classification AASHTO Classification LL PL PI Cc Cu P-6 1 - 4 FAT CLAY (CH) A-7-6(33) 51 17 34

P-7 1 - 4 LEAN CLAY (CL) A-7-6(29) 49 19 30

P-8 2 - 3 FAT CLAY (CH) A-7-6(30) 50 20 30

Boring ID Depth D100 D60 D30 D10 %Gravel %Sand %Silt %Clay P-6 1 - 4 0.075 0.0 0.0 90.9

P-7 1 - 4 0.075 0.0 0.0 91.9

P-8 2 - 3 0.075 0.0 0.0 92.1

PROJECT: Subgrade Evaluation & Pavement Thickness Design PROJECT NUMBER: 22165009

SITE: Eagle Meadow Filing 2A CLIENT: CivilArts Dacono, Colorado Longmont, Colorado 1242 Bramwood Place Longmont, Colorado EXHIBIT: B-8 LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS & AASHTO COMBINED 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2012.GDT 2/9/16 TERRACON2012.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE COMBINED AASHTO & USCS SIZE: GRAIN REPORT. ORIGINAL FROM IF SEPARATED VALID NOT ARE TESTS LABORATORY MOISTURE-DENSITY RELATIONSHIP ASTM D698/D1557

135

130 Source of Material COMP 3 4 6 7 @ 1 - 4 feet Description of Material LEAN to FAT CLAY (CL/CH)

125 Remarks: Composite sample from test borings P-3, 4, 6 and 7 at 1 to 4 feet

120 Test Method ASTM D698 Method A

115

TEST RESULTS 104.5 PCF 110 Maximum Dry Density Optimum Water Content 18.5 % Percent Fines %

105 ATTERBERG LIMITS DRY DENSITY, pcf LL PL PI 100

ZAV for G

ZAV for G 80 ZAV for Gs = 2.8

s = 2.7

s = 2.6

75 0 5 10 15 20 25 30 35 40 45 WATER CONTENT, % PROJECT: Subgrade Evaluation & Pavement Thickness Design PROJECT NUMBER: 22165009

SITE: Eagle Meadow Filing 2A CLIENT: CivilArts Dacono, Colorado Longmont, Colorado 1242 Bramwood Place Longmont, Colorado EXHIBIT: B-9 LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. COMPACTION - V2 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2012.GDT 2/9/16 TERRACON2012.GDT PAVEMENT.GPJ 2A FILING MEADOW - 22165009.EAGLE V2 COMPACTION REPORT. ORIGINAL FROM IF SEPARATED VALID NOT ARE TESTS LABORATORY SWELL CONSOLIDATION TEST

0 AXIAL STRAIN, % -2

-4

-6

-8

-10 100 1,000 10,000 105

PRESSURE, psf

Specimen Identification Classification , pcf WC, % COMP 3 4 6 70.1 ft LEAN to FAT CLAY (CL/CH) - REMOLDED 100 18

NOTES: Sample recompacted at about optimum M.C. to about 95% of the standard Proctor maximum dry density (ASTM D698). Sample exhibited 2.4 percent expansion upon wetting under an applied pressure of 200 psf.

0 AXIAL STRAIN, % -2

-4

-6

-8

-10 100 1,000 10,000 105

PRESSURE, psf

Specimen Identification Classification , pcf WC, % COMP 3 4 6 70.2 ft LEAN to FAT CLAY (CL/CH) - REMOLDED 100 20

NOTES: Sample recompacted at about 2 percent above optimum M.C. to about 95% of the standard Proctor maximum dry density (ASTM D698). Sample exhibited 1.8 percent expansion upon wetting under an applied pressure of 200 psf.

PROJECT: Subgrade Evaluation & Pavement Thickness PROJECT NUMBER: 22165009 Design SITE: Eagle Meadow Filing 2A CLIENT: CivilArts Dacono, Colorado Longmont, Colorado 1242 Bramwood Place Longmont, Colorado EXHIBIT: B-11 LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. TC_CONSOL_STRAIN-USCS-NO ASTM 22165009.EAGLE MEADOW FILING 2A PAVEMENT.GPJ TERRACON2012.GDT 2/9/16 TERRACON2012.GDT PAVEMENT.GPJ 2A FILING MEADOW 22165009.EAGLE ASTM TC_CONSOL_STRAIN-USCS-NO REPORT. ORIGINAL FROM IF SEPARATED VALID NOT ARE TESTS LABORATORY 1901 Sharp Point Dr Suite C Fort Collins, Colorado 80525 (970) 484-0359 FAX (970) 484-0454 RESISTANCE R-VALUE & EXPANSION PRESSURE OF COMPACTED SOIL AASHTO T-190 CLIENT: CivilArts DATE OF TEST: 01-Feb-16 PROJECT: Eagle Meadow Filing 2A LOCATION: P-3 at 1 to 4 feet TERRACON NO. 22165009 CLASSIFICATION: FAT CLAY (CH); A-7-6 (34) SAMPLE DATA TEST RESULTS

TEST SPECIMEN NO. 1 2 3 COMPACTION PRESSURE (PSI) 65 0 0 DENSITY (PCF) MOISTURE CONTENT (%) EXPANSION PRESSURE (PSI) 0.00 0.00 0.00 HORIZONTAL PRESSURE @ 160 PSI 0 0 0 SAMPLE HEIGHT (INCHES) 0.00 0.00 0.00 EXUDATION PRESSURE (PSI) 428.2 CORRECTED R-VALUE UNCORRECTED R-VALUE R-VALUE @ 300 PSI EXUDATION PRESSURE = < 5 Material meets AASHTO T-190, Note 2 criteria.

100

VALUE -

R 40

0 0 100 200 300 400 500 600 700 800 EXUDATION PRESSURE - PSI

Exhibit B-12

APPENDIX C

SUPPORTING DOCUMENT GENERAL NOTES DESCRIPTION OF SYMBOLS AND ABBREVIATIONS

Water Initially (HP) Hand Penetrometer Encountered Water Level After a (T) Torvane Auger Split Spoon Specified Period of Time

Water Level After a Specified Period of Time (b/f) Standard Penetration Test (blows per foot) Shelby Tube Macro Core Water levels indicated on the soil boring (PID) Photo-Ionization Detector logs are the levels measured in the borehole at the times indicated. (OVA) Organic Vapor Analyzer

SAMPLING Groundwater level variations will occur Ring Sampler Rock Core over time. In low permeability soils, FIELD TESTS WATER LEVEL accurate determination of groundwater levels is not possible with short term water level observations. Grab Sample No Recovery

DESCRIPTIVE SOIL CLASSIFICATION Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency.

LOCATION AND ELEVATION NOTES Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracy of such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey was conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic maps of the area.

RELATIVE DENSITY OF COARSE-GRAINED CONSISTENCY OF FINE-GRAINED SOILS BEDROCK SOILS (More than 50% retained on No. 200 sieve.) (50% or more passing the No. 200 sieve.) Density determined by Consistency determined by laboratory shear strength testing, Standard Penetration Resistance field visual-manual procedures or standard penetration Includes gravels, sands and silts. resistance Standard Standard Standard Ring Descriptive Unconfined Ring Ring Descriptive Penetration or Penetration or Penetration or Descriptive Sampler Term Compressive Sampler Sampler Term N-Value N-Value N-Value Term Blows/Ft. (Consistency) Strength, Blows/Ft. Blows/Ft. (Density) Blows/Ft. Blows/Ft. Blows/Ft. (Consistency) Qu, psf

Very Loose 0 - 3 0 - 5 Very Soft less than 500 0 - 1 < 3 < 24 < 20 Weathered

Loose 4 - 9 6 - 14 Soft 500 to 1,000 2 - 4 3 - 5 24 - 35 20 - 29 Firm

Medium Dense 10 - 29 15 - 46 Medium-Stiff 1,000 to 2,000 4 - 8 6 - 10 36 - 60 30 - 49 Medium Hard

STRENGTH TERMS Dense 30 - 50 47 - 79 Stiff 2,000 to 4,000 8 - 15 11 - 18 61 - 96 50 - 79 Hard

Very Dense > 50 >_ 80 Very Stiff 4,000 to 8,000 15 - 30 19 - 36 > 96 >79 Very Hard

Hard > 8,000 > 30 > 36

RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY

Descriptive Term(s) Percent of Major Component Particle Size of other constituents Dry Weight of Sample Trace < 15 Boulders Over 12 in. (300 mm) With 15 - 29 Cobbles 12 in. to 3 in. (300mm to 75mm) Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm) Sand #4 to #200 sieve (4.75mm to 0.075mm Silt or Clay Passing #200 sieve (0.075mm) RELATIVE PROPORTIONS OF FINES PLASTICITY DESCRIPTION Descriptive Term(s) Percent of Term Plasticity Index of other constituents Dry Weight Non-plastic 0 Trace < 5 Low 1 - 10 With 5 - 12 Medium 11 - 30 Modifier > 12 High > 30

Exhibit C-1 UNIFIED SOIL CLASSIFICATION SYSTEM Soil Classification A Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests Group Group Name B Symbol E F Gravels: Clean Gravels: Cu  4 and 1  Cc  3 GW Well-graded gravel C F More than 50% of Less than 5% fines Cu  4 and/or 1  Cc  3 E GP Poorly graded gravel F,G,H coarse fraction retained Gravels with Fines: Fines classify as ML or MH GM Silty gravel Coarse Grained Soils: C F,G,H on No. 4 sieve More than 12% fines Fines classify as CL or CH GC Clayey gravel More than 50% retained E SW Well-graded sand I on No. 200 sieve Sands: Clean Sands: Cu  6 and 1  Cc  3 D I 50% or more of coarse Less than 5% fines Cu  6 and/or 1  Cc  3 E SP Poorly graded sand G,H,I fraction passes No. 4 Sands with Fines: Fines classify as ML or MH SM Silty sand D sieve More than 12% fines Fines classify as CL or CH SC Clayey sand G,H,I PI  7 and plots on or above “A” line J CL Lean clay K,L,M Inorganic: J K,L,M Silts and Clays: PI  4 or plots below “A” line ML Silt Liquid limit less than 50 Liquid limit - oven dried Organic clay K,L,M,N Organic:  0.75 OL Fine-Grained Soils: Liquid limit - not dried Organic silt K,L,M,O 50% or more passes the PI plots on or above “A” line CH Fat clay K,L,M No. 200 sieve Inorganic: K,L,M Silts and Clays: PI plots below “A” line MH Elastic Silt Liquid limit 50 or more Liquid limit - oven dried Organic clay K,L,M,P Organic:  0.75 OH Liquid limit - not dried Organic silt K,L,M,Q Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat

A Based on the material passing the 3-inch (75-mm) sieve H If fines are organic, add “with organic fines” to group name. B If field sample contained cobbles or boulders, or both, add “with cobbles I If soil contains  15% gravel, add “with gravel” to group name. or boulders, or both” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly whichever is predominant. graded gravel with silt, GP-GC poorly graded gravel with clay. L If soil contains  30% plus No. 200 predominantly sand, add “sandy” to D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded group name. sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded M If soil contains  30% plus No. 200, predominantly gravel, add sand with silt, SP-SC poorly graded sand with clay “gravelly” to group name. 2 N (D ) PI  4 and plots on or above “A” line. E 30 O Cu = D60/D10 Cc = PI  4 or plots below “A” line. P D10 x D60 PI plots on or above “A” line. Q F PI plots below “A” line. If soil contains  15% sand, add “with sand” to group name.

G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.

Exhibit C-2 ROCK CLASSIFICATION (Based on ASTM C-294)

Sedimentary Rocks

Sedimentary rocks are stratified materials laid down by water or wind. The sediments may be composed of particles or pre-existing rocks derived by mechanical weathering, evaporation or by chemical or organic origin. The sediments are usually indurated by cementation or compaction.

Chert Very fine-grained siliceous rock composed of micro-crystalline or cyrptocrystalline quartz, chalcedony or opal. Chert is various colored, porous to dense, hard and has a conchoidal to splintery fracture.

Claystone Fine-grained rock composed of or derived by erosion of silts and clays or any rock containing clay. Soft massive and may contain carbonate minerals.

Conglomerate Rock consisting of a considerable amount of rounded gravel, sand and cobbles with or without interstitial or cementing material. The cementing or interstitial material may be quartz, opal, calcite, dolomite, clay, iron oxides or other materials.

Dolomite A fine-grained carbonate rock consisting of the mineral dolomite [CaMg(CO3)2]. May contain noncarbonate impurities such as quartz, chert, clay minerals, organic matter, gypsum and sulfides. Reacts with hydrochloric acid (HCL).

Limestone A fine-grained carbonate rock consisting of the mineral calcite (CaCO3). May contain noncarbonate impurities such as quartz, chert, clay minerals, organic matter, gypsum and sulfides. Reacts with hydrochloric acid (HCL).

Sandstone Rock consisting of particles of sand with or without interstitial and cementing materials. The cementing or interstitial material may be quartz, opal, calcite, dolomite, clay, iron oxides or other material.

Shale Fine-grained rock composed of or derived by erosion of silts and clays or any rock containing clay. Shale is hard, platy, or fissile and may be gray, black, reddish or green and may contain some carbonate minerals (calcareous shale).

Siltstone Fine grained rock composed of or derived by erosion of silts or rock containing silt. Siltstones consist predominantly of silt sized particles (0.0625 to 0.002 mm in diameter) and are intermediate rocks between claystones and sandstones and may contain carbonate minerals.

Exhibit C-3 STRUCTURAL NUMBER SN = 3.1

Project Manager: Project No. FLEXIBLE PAVEMENT DESIGN NOMOGRAPH EXHIBIT ESW 22165009 Drawn By: Scale: ESW CIVILARTS Check By: Date: SUBGRADE EVALUATION & PAVEMENT THICKNESS DESIGN EDB 2/23/2016 EAGLE MEADOW FILING 2A C-4 Approved By: 1242 Bramwood Place Longmont, Colorado 80501 ESW PH. (303) 776-3921 FAX. (303) 776-4041 CITY OF DACONO, COLORADO

PAVEMENT THICKNESS DESIGN CALCULATIONS

PAVEMENT DESIGN DATA

. R-Value = Less than 5 . 18-kip Equivalent Daily Load Application (EDLA) = 10 . Serviceability Index (SI) = 2.0 . Design Structural Number (SN) = 3.1 (See Design Nomograph)

FLEXIBLE PAVEMENT DESIGN EQUATION

SN = C1D1 + C2D2 + C3D3

C1 = 0.40 - Strength Coefficient - Asphalt Concrete (AC) C2 = 0.12 - Strength Coefficient - Aggregate Base Course (ABC) C3 = 0.11 - Strength Coefficient – Lime Treated Subgrade (LTS)

D1 - Depth of Asphalt Concrete (inches) D2 - Depth of Aggregate Base Course (inches) D3 - Depth of Lime Treated Subgrade (LTS) (inches)

COMPOSITE PAVEMENT SECTION (AC + ABC)

SN = 3.1 = (0.40)(5”) + (0.12)(9.2”) D1 = 5 inches of Asphalt Concrete D2 = 9.2 inches of Aggregate Base Course

Use: 5 inches AC + 9 inches ABC Constructed on modified subgrade as outlined in the report

COMPOSITE PAVEMENT SECTION on LTS (AC + ABC + LTS)

SN = 3.1 = (0.40)(4”) + (0.12)(5.2”) + (0.11)(8”) D1 = 4 inches of Asphalt Concrete D2 = 5.2 inches of Aggregate Base Course D3 = 8 inches of Lime Treated Subgrade (LTS)

Use: 4 inches AC + 6 inches ABC + 8 inches LTS Constructed on modified subgrade as outlined in the report

Note: The City of Dacono, Colorado Standards & Specifications for Design and Construction of Public Improvements (September 2010, Revised January 2015) do not allow the use of full- depth asphalt pavement sections.

Exhibit C-5