13-13-RRSegD2-Final PavementReport.pdf

PAVEMENT ENGINEERING STUDY

FOR

RONALD REAGAN BLVD - SEGMENT D2

FROM EAST OF CR 245 TO WEST OF RATTLESNAKE RD

WILLIAMSON COUNTY, TEXAS

Project No. AAA24-036-00 February 21, 2025

Mr. Chase W. Myers, P.E.

American Structurepoint, Inc.

3711 South MoPac Expressway, Building 1, Suite 350 Austin, Texas 78746

RE: Geotechnical Engineering Study Ronald Reagan Blvd - Segment D2 From East of CR 245 to West of Rattlesnake Rd Williamson County, Texas

Dear Mr. Myers:

RABA KISTNER Consultants Inc. (RKCI) is pleased to submit the report of our Geotechnical Engineering Study for the above-referenced project. This study was performed in accordance with the Subconsultant Agreement between American Structurepoint, Inc. and Raba Kistner, Inc., dated April 9, 2024 and Supplemental Work Authorization #1, dated August 28, 2024. The purpose of this study was to perform field exploration and laboratory testing programs to classify and characterize subsurface conditions at the site, and to prepare an engineering report presenting pavement design recommendations and construction considerations for the project.

The following report contains our design recommendations and considerations based on our current understanding of information provided to us at the time of this study and our borings drilled at the site.

We appreciate the opportunity to be of service to you on this project. Should you have any questions about the information presented in this report, or if we may be of additional assistance with value engineering or on the materials testing-quality control program during construction, please call.

Very truly yours, RABA KISTNER CONSULTANTS, INC.

Loren I. Clifford, E.I.T. Richard T. Shimono, P.E.

Graduate Engineer Project Manager

LIC/RSK/RTS: mg

Attachments

Copies Submitted: Above (1-Electronic)

Raba Kistner, Inc.

8100 Cameron Road, Suite B-150

Austin, TX 78754 www.rkci.com

P 512.339.1745 F 512.339.6174

F-3257

2/21/2025

GEOTECHNICAL ENGINEERING STUDY

For

RONALD REAGAN BLVD - SEGMENT D2

FROM EAST OF CR 245 TO WEST OF RATTLESNAKE RD

WILLIAMSON COUNTY, TEXAS

Prepared for

AMERICAN STRUCTUREPOINT, INC.

Austin, Texas

Prepared by

RABA KISTNER CONSULTANTS, INC.

Austin, Texas

PROJECT NO. AAA24-036-00

TABLE OF CONTENTS

i

INTRODUCTION

BRIDGE AND RETAINING WALL REPORT

PROJECT DESCRIPTION

LIMITATIONS

BORINGS AND LABORATORY TESTS

BORING EXPLORATIONS

Dynamic Cone Penetrometer

LABORATORY TESTING

Sulfate Testing Organic Testing Moisture-Density Relationship of Subgrade Soil pH-Lime Series Triaxial Compression for Disturbed Soils

GENERAL SITE CONDITIONS

GEOLOGY

STRATIGRAPHY

GROUNDWATER

PAVEMENT RECOMMENDATIONS

TRAFFIC INFORMATION

DESIGN METHOD

RECOMMENDED PAVEMENT SECTIONS

Recommended Pavement Section - Driveways

PAVEMENT CONSTRUCTION CONSIDERATIONS

SUBGRADE PREPARATION

DRAINAGE CONSIDERATIONS

EXCAVATION EQUIPMENT

SUBGRADE IMPROVEMENT

Lime Treated Subgrade Embankment Fill

FLEXIBLE BASE COURSE

PRIME COAT

TACK COAT

ASPHALTIC CONCRETE BASE COURSE

ASPHALTIC CONCRETE SURFACE COURSE

PORTLAND CEMENT CONCRETE

MISCELLANEOUS PAVEMENT RELATED CONSIDERATIONS

Pavement Maintenance

TABLE OF CONTENTS

ii

Construction Traffic

CONSTRUCTION RELATED SERVICES

CONSTRUCTION MATERIALS TESTING AND OBSERVATION SERVICES

BUDGETING FOR CONSTRUCTION TESTING

ATTACHMENTS

The following figures are attached and complete this report:

Site Location Map .............................................................................................................................. Figure 1 Geologic Map ..................................................................................................................................... Figure 2 Boring Location Map .......................................................................................................................... Figure 3 Logs of Borings ........................................................................................................................ Figures 4 to 21 Key to Terms and Symbols ............................................................................................................... Figure 22 Results of Soil Analyses .................................................................................................................... Figure 23 Grain Size Curves ................................................................................................................. Figure 24a to 24d Boring Logs and Lab Data from B/RW Borings .............................................................................. Appendix A Dynamic Cone Penetration Results ............................................................................................... Appendix B Organic and Bulk Sample Testing Results ..................................................................................... Appendix C Potential Vertical Rise (PVR) Printouts .........................................................................................Appendix D FPS-21 Output Files and ATG | DCCM Memorandum...................................................................Appendix E Williamson County Driveway Exhibit ............................................................................................ Appendix F Important Information About Your Geotechnical Engineering Report

INTRODUCTION

RABA KISTNER Consultants Inc. (RKCI) has completed the authorized subsurface exploration and pavement analysis for the construction of a new 2-lane facility to the north of the existing alignment of Ronald Reagan Boulevard in Williamson County, Texas. This report briefly describes the procedures utilized during this study and presents our findings along with our pavement design recommendations and construction considerations for use in the design and reconstruction of the roadway.

An overview of the project site extents and surrounding site features is shown on the Site Location Map, Figure 1. The geologic conditions of the site and the surrounding vicinity are shown on the Geology Map, Figure 2.

BRIDGE AND RETAINING WALL REPORT

RKCI’s scope of services includes a separate report providing recommendations for a bridge and retaining walls. The subsurface exploration program for the bridge and retaining wall report included six drilled borings (labeled B-1 through B-9, and RW-1 through RW-11), which were used as supplementary information in the preparation of this report. For ease of reference, these boring logs are presented in Appendix A.

PROJECT DESCRIPTION

Under consideration in this study is the construction of a new 2-lane roadway facility just north of the existing Ronald Reagan Boulevard alignment. The Segment D2 under consideration extends 2.12 miles from east of County Road 245 on the west end, to Sun City Boulevard on the east end, approximately from Station 1980+00 to Station 2092+00 in Georgetown, Williamson County, Texas. We understand the proposed new facility is a 2-lane roadway with 12 ft lanes, shoulders, turn lanes, and intersection improvements. Based on the Ronald Reagan (Segment D) Schematic Layout prepared by the Rodriguez Transportation Group we understand that this new facility will serve both east and west bound traffic for the foreseeable future until it is repurposed as the westbound frontage road of the ultimate Ronald Reagan Boulevard Controlled Access Roadway.

LIMITATIONS

This engineering report has been prepared in accordance with accepted Geotechnical Engineering practices in the region of central Texas and for the use of American Structurepoint, Inc. and its representatives for design purposes. This report may not contain sufficient information for purposes of other parties or other uses. This report is not intended for use in determining construction means and methods. The attachments and report text should not be used separately.

The recommendations submitted in this report are based on the data obtained from 18 borings drilled at this site and our understanding of the project information provided to us. If the project information described in this report is incorrect, is altered, or if new information is available, we should be retained to review and modify our recommendations.

This report may not reflect the actual variations of the subsurface conditions across the site. The nature and extent of variations across the site may not become evident until construction commences. The construction process itself may also alter subsurface conditions. If variations appear evident at the time of construction, it may be necessary to reevaluate our recommendations after performing on-site observations and tests to establish the engineering impact of the variations.

The scope of our Geotechnical Engineering Study does not include an environmental assessment of the air, soil, rock, or water conditions either on or adjacent to the site. No environmental opinions are presented in this report.

If final grade elevations differ from the schematic and cross section drawings by more than plus or minus 2 ft, our office should be informed about these changes. If needed and/or if desired, we will reexamine our analyses and make supplemental recommendations.

BORINGS AND LABORATORY TESTS

BORING EXPLORATIONS

Pavement subsurface conditions at the site were explored by 18 borings (labeled Borings P-1 through P-18) drilled using a truck-mounted drilling rig. The approximate locations of these borings as well as the borings performed for the bridge and retaining wall report are shown on the Boring Location Map, Figure 3. The boring locations were documented in the field utilizing a hand-held GPS device. The borings were drilled to approximate depths of 15 ft below the existing ground surface. A summary table including the approximate location and elevation of each of the borings is presented below.

Boring No.

Coordinates Boring Surface

Elevation*

(ft) Latitude Longitude

P-1 30.736973 -97.770424 909

P-2 30.736719 -97.768952 894

P-3 30.736940 -97.766866 911

P-4 30.737070 -97.764481 933

P-5 30.737779 -97.761257 906

P-6 30.738516 -97.759175 878

P-7 30.739654 -97.756640 901

P-8 30.740548 -97.754444 925

P-9 30.741357 -97.752263 931

P-10 30.742238 -97.749813 921

P-11 30.742967 -97.747041 924

P-12 30.743280 -97.745063 923

P-13 30.743088 -97.742694 898

P-14 30.742877 -97.740021 871

P-15 30.742893 -97.737647 846

P-16 30.748397 -97.729305 885

Boring No.

Coordinates Boring Surface

Elevation*

(ft) Latitude Longitude

P-17 30.750262 -97.727698 897

P-18 30.751824 -97.726021 901

* Boring surface elevation estimated from Google Earth.

During drilling operations, the following samples were collected.

Type of Sample Number Collected

Split-Spoon (with Standard Penetration Test) 57

Undisturbed Shelby Tube 2

NX Rock Core 141 ft

Relatively hard soils and decomposed limestone were sampled using a standardized 1.5-inch inner diameter split-spoon in accordance with ASTM D1586 - Standard Test Method for Standard Penetration Test (SPT) and Split-Barrel Sampling of Soils. SPT results (N-values) are noted as “blows per ft” on the boring logs and on Figure 23. The N-value is the number of blows required to drive a split-spoon sampler 1 ft into soil/weak rock with a falling, 140-lb hammer at a 30-inch drop following 6 inches of seating blows.

Where hard or dense materials were encountered, the tests were terminated at 50 blows even if one foot of penetration had not been achieved. When all 50 blows fall within the first 6 in. (seating blows), refusal (“ref”) will be noted on the boring logs and on Figure 23.

One soil sample was completed using a 3-in outer diameter thin-walled tube, which was pushed into the soil in general accordance with ASTM D 1587 - Standard Practice for Thin-Walled Tube Sampling of Soils for Geotechnical Purposes. The samples were extruded in the field and a pocket penetrometer was used to obtain an estimate of the shear strength of the sample.

Rock coring was conducted in general accordance with ASTM D2113 – Standard Practice for Rock Core Drilling and Sampling of Rock for Site Exploration. The core recovery (REC) presented on the logs are the total length of the recovered material divided by the attempted run length during coring activities, presented as a percentage. The Rock Quality Designation (RQD) is the sum of the length of all recovered rock segments measuring 4 inches or more divided by the attempted run length during coring activities, presented as a percentage.

Classification and field test results were recorded onto field logs, which included a visual description in general accordance with ASTM D 2488 – Visual Description and Identification of Soils. After field logging, the individual samples were either sealed in plastic bags or wrapped in plastic to prevent loss of moisture and were transported to our laboratory for further evaluation.

Upon completion of the sampling activities, the boreholes were backfilled with auger cuttings and bentonite chips and patched with asphalt. Samples will be retained in our laboratory for 30 days after submittal of this report. Other arrangements may be provided at the request of the Client.

Dynamic Cone Penetrometer

Dynamic Cone Penetrometer (DCP) testing was conducted at several boring locations in accordance with ASTM D6951. Employing a 17.6-pound hammer, the DCP tip is driven into the subgrade soil by repeatedly lifting and dropping the hammer from a 22.6-inch height. The tip penetration for a given number of hammer blows is measured and recorded until achieving a maximum penetration depth of 24 inches or refusal.

The DCP was utilized for estimating the subgrade modulus of the in-situ soils at the site. A summary of the DCP estimated subgrade modulus results are shown in the table below and the detailed results, including correlation equations for determining the subgrade moduli, are presented in Appendix B.

Boring No. Subgrade Modulus (psi)

P-01 53,800

P-03 28,100

P-05 96,700

P-07 52,100

P-09 56,000

P-11 60,400

P-13 96,700

P-15 24,800

P-16 67,500

P-17 16,100

P-18 56,900

AVG. 55,400

AVG. – ST.DEV. 33,200

LABORATORY TESTING

Each sample was visually classified in the laboratory by a member of our geotechnical engineering staff.

Classification testing, which included moisture contents, Atterberg Limits, and grain size analyses, were completed on select samples for classification in general accordance with ASTM D 2487 - Standard Classification of Soils for Engineering Purposes (Unified Soil Classification System). Additional laboratory testing was completed on select samples to evaluate the geotechnical engineering properties of the subsurface soils existing at the site. Additionally, testing was performed on bulk samples, Samples BS-1 through BS-4.

Type of Sample Type of Test Number Conducted

Borings (P-01 through P-18)

Natural Moisture Content (Tex-103-E) 59

Atterberg Limits (Tex- 104-E, Tex-105-E, Tex-106-E) 16

Sieve Analysis (Tex-110-E) 17

Sulfate Concentration (Tex-145-E) 4

Type of Sample Type of Test Number Conducted

Soil Organic Content (Tex-148-E) 3

Bulk Samples (BS-1 through BS-4)

Atterberg Limits (Tex- 104-E, Tex-105-E, Tex-106-E) 4

Sieve Analysis, with Hydrometer (Tex-110-E) 3

Sieve Analysis (Tex-110-E) 1

Soil pH-Lime Relationship (Tex-121-E, Pt. III) 1

Moisture-Density Relationship (Tex-114-E) 2

Texas Triaxial Compression Series (Tex-117-E) 1

The results of all laboratory tests for the pavement borings are presented in graphical or numerical form on the boring logs illustrated on Figures 4 through 21. A key to classification terms and symbols used on the logs is presented on Figure 22. The results of the laboratory and field testing are also tabulated on Figure 23 for ease of reference. The results of the sieve analysis have been plotted on the attached Grain Size Curve, Figure 24. A summary of the results of the sulfate concentrations, organic content, and bulk sample testing is presented in the following sections.

Sulfate Testing

Sulfate testing was performed on selected samples from our borings. The purpose of the sulfate testing was to determine the concentration of soluble sulfates in the subgrade soils, in order to investigate the potential for an adverse reaction to lime in sulfate-containing soils. The adverse reaction, referred to as sulfate-induced heave, has been known to cause cohesive subgrade soils to swell in short periods of time, resulting in pavement heaving and possible failure.

Boring No.

Depth Below Existing Ground Surface (ft) Soil Type

Sulfate Concentration

(ppm)

P-3 0 to 1.5 Dark Brown Clayey Gravel (GC) 160

P-4 2 to 3.5 Reddish-Brown Sandy Silty Clay (CL-ML) 140

P-6 0 to 1.5 Dark Brown Clayey Gravel (GC) 120

P-15 0 to 1.5 Tan Gravel with Silty Clay (GP-GC) 120

Based on the laboratory test results, the reported sulfate concentration values were generally determined to be on the order of 160 parts per million (ppm) or less. Reported sulfate concentrations above 3,000 ppm are known to cause sulfate induced heaving when the soils are mixed with lime. It should be understood that the identification of sulfates based on discrete soil samples cannot totally identify sulfates in all areas.

If the option for lime is considered, a quality assurance program should be implemented to assist in reducing the risk of sulfate induced heaving.

Organic Testing

Organic testing was performed by Beyond Engineering & Testing, LLC. on selected samples from our borings in accordance with Tex-148-E. The purpose of the organic content testing was to determine the concentration of organics in the subgrade soils. A summary of the test results is shown in the table below and the detailed results are presented in Appendix C.

Boring No.

Depth*

(ft) Soil Type Soil Organic Content

P-10 2 to 3.5 Brown Fat Clay (CH) 0.3

P-13 2 to 3.5 Reddish-Brown Clayey Gravel (GC) 0.1

P-15 4 to 5.5 Tan Gravel with Silty Clay (GP-GC) 0.1 *Below existing grades at the time of this study

Based on the laboratory test results, the reported sulfate concentration values were generally determined to be on the order of 0.1 to 0.3 percent. Reported organic concentrations above 1.0 percent are known to decrease the effectiveness of lime treatment of subgrade soil.

It should be understood that the identification of organics based on discrete soil samples cannot totally identify the presence of organics in all areas. If further organics testing is performed and higher organic contents are encountered, we recommend that 2 percent lime be added to the recommended concentration of lime for all areas. Moreover, we also recommend that the unconfined compressive strength of the lime treated soil be at least 50 psi. Further discussion of lime treatment is presented in the Lime Treated Subgrade section of this report.

Moisture-Density Relationship of Subgrade

A moisture-density relationship was completed on the bulk sample in general accordance with TxDOT, Tex-114-E laboratory procedures. In addition, Atterberg Limits and sieve analysis testing was performed to characterize the bulk sample. A summary of the test results is shown in the table below and the detailed results are presented in Appendix C.

Sample Maximum Dry Density (pcf)

Optimum Moisture Content (%) Subgrade Classification

BS-1 82.5 30.2 Dark Brown Fat Clay (CH)

BS-2 93.9 21.3 Dark Brown Fat Clay (CH)

Soil pH-Lime Series

Soil pH-Lime series testing was conducted on selected samples collected from Sample BS-1, and the testing was performed in general accordance with TxDOT Tex-121-E Part III laboratory procedures. The results of the soil pH-lime testing are presented in the table below and the detailed results are presented in Appendix C.

pH

Sample Baseline 2% Lime 4% Lime 6% Lime 8% Lime 10% Lime

BS-1 8.38 11.81 12.29 12.36 12.37 12.38

Triaxial Compression for Disturbed Soils

Triaxial compression testing was conducted on the bulk sample in general accordance with TxDOT, Tex-117-E laboratory procedures. The results of the triaxial compression testing are presented in the table below and the detailed results are presented in Appendix C.

Sample Friction Angle (degrees) Cohesion (psi) Texas Triaxial

Classification

BS-1 25.8 7.1 4.1

GENERAL SITE CONDITIONS

GEOLOGY

A review of the Geologic Atlas of Texas, Austin Sheet, indicates that this site is naturally underlain with the soils/rock (limestone) of the Edwards Group. Edwards limestone is generally considered hard in induration and typically contains harder zones/seams of chert and dolomite. Edwards limestone also typically contains karstic features in the form of open and/or clay-filled vugs, voids, and/or solution cavities that form as a result of solution movement through fractures in the rock mass.

Key geotechnical engineering considerations for development supported on this formation will be the depth to rock, the expansive nature of the overlying clays, the condition of the rock, and the presence/absence of karstic features.

STRATIGRAPHY

The subsurface conditions encountered at the boring locations are shown on the boring logs, Figures 4 through 21. These boring logs represent our interpretation of the subsurface conditions based on the field logs, visual examination of field samples by our personnel, and test results of selected field samples. Each stratum has been designated by grouping soils that possess similar physical and engineering characteristics.

The lines designating the interfaces between strata on the boring logs represent approximate boundaries.

Transitions between strata may be gradual.

Stratum I consists of stiff to hard, dark brown to brown fat clay (CH) and clayey gravel (GC). These soils are classified as plastic to highly plastic based on measured plasticity indices ranging from 32 to 59.

Measured moisture contents range from 1 to 29 percent. Standard Penetration Test (SPT) N-values range from 11 blows per ft to 50 blows for 7 inches. Shear strength values were measured on the order of 2.3 tsf based on data from a single pocket penetrometer test. Based on grain size analyses, the percentage of fines (percent passing a No. 200 sieve) ranges from 29 to 95 percent. This stratum extends to depths ranging from 1 to 4 ft below the existing ground surface in our borings and was not encountered in Borings P-8, or P-12 through P-13.

Stratum II consists of loose to very dense, tan and reddish-brown clayey gravel (GC) and clayey sand (SC).

These soils are classified as low plasticity to plastic based on measured plasticity indices ranging from 6 to

35. Measured moisture contents range from 1 to 35 percent. SPT N-values range from 9 blows per ft to 50 blows for 1 inch of penetration. Based on grain size analyses, the percentage of fines ranges from 8 to 59 percent. This stratum generally extends to depths ranging from 2 to 5 ft below the existing ground surface in our borings and was not encountered in Borings P-3, P-5, P-6, P-9, P-11, P-12 or P-14. Boring P- 15 terminates in this stratum.

Stratum III consists of hard, light tan and gray, moderately to highly fractured and weathered limestone.

SPT N-values range from 50 blows per ft to refusal for 1 inch of penetration. Core recovery values range from 28 to 100 percent, and RQD values range from 0 to 100 percent. All borings except Boring P-15 terminate in this stratum.

GROUNDWATER

Based on information provided by the borehole logger, groundwater seepage was not observed during the field exploration phase. However, it is possible for groundwater to exist beneath this site at shallow depths on a transient basis, particularly at the clay/limestone interface, within weathered limestone seams, and following periods of precipitation. Fluctuations in groundwater levels occur due to variation in rainfall and surface water run-off. The construction process itself may also cause variations in the groundwater level.

PAVEMENT RECOMMENDATIONS

The following pavement design recommendations presented in this report were prepared in accordance with the Williamson County DCM.

SUBGRADE CONDITIONS

We have assumed the subgrade in pavement areas will consist of the existing near surface soils that were encountered in our borings. The near surface soils at the site are generally comprised of dark brown fat clays (stratum I) and gray and tan sandy clayey sands (stratum II). Based on the results of DCP testing, our local experience, and to account for potential variability, a subgrade modulus of 20 ksi has been used for design of the pavement section. The 20 ksi is the maximum allowed subgrade modulus for pavement design in accordance with the DCM. Based on the Triaxial Compression tests performed on the bulk samples, a Texas Triaxial Classification of 4.1 was used to represent the near surface subgrade soils at this site.

Swell/Heave Potential

The anticipated ground movements due to swelling of the underlying soils were estimated for pavement construction using the empirical procedure, Texas Department of Transportation (TxDOT) Tex-124-E, Method for Determining the Potential Vertical Rise (PVR). The PVR analyses were estimated assuming an active zone to the lesser of 15 ft and the soil/limestone interface, a 1-1/2 ft thick pavement section, and dry to average moisture conditions. Due to relatively minimal variability across the site, two subsurface scenarios were evaluated to represent the best case (minimum) and worst case (maximum) PVR at the site. The results of our analysis indicate the PVR at the site ranges from approximately 1.3 to 2 inches.

Printouts of the PVR calculation sheets are presented in Appendix D.

Subgrade Improvement

In accordance with the Williamson County DCM, we understand a limiting PVR of 2 inches is desired. Based on our findings and our recommended pavement sections, the PVR is expected to not exceed 2 inches along the project limits; therefore, no subgrade improvement is required to reduce potential expansive soil related movements.

However, as a means to reduce the risk of subgrade disturbance during construction, removal and replacement or lime stabilization of any surficial clay subgrade soils is still recommended to provide a construction platform.

TRAFFIC INFORMATION

Based on the traffic projection data memorandum prepared by ATG/DCCM, dated January 15, 2025, an initial ADT of 9,900 vehicles per day in 2028, an ADT of 19,500 vehicles per day in 2048, and 19.8 percent trucks resulting in 20-year design life ESALs of 8,605,000 were used for the pavement section design. To approximate traffic values for the future west bound frontage road only, the above values have been reduced by approximately half. For additional details about the traffic information, this memorandum is included in Appendix E.

An Average Ten Heaviest Wheel Loads Daily (ATHWLD) of 12,100 pounds and a percentage of tandem axles of 30 percent were selected for the Modified Triaxial Check, per the traffic analysis.

DESIGN METHOD

The pavement design was performed in general accordance with the recommendations presented in the DCM. The computer program FPS 21 was utilized for evaluating the required flexible pavement thickness.

FPS 21 is a mechanistic-empirical design procedure evaluating pavement performance based on serviceability index and traffic loading. Similar to AASHTO 93, FPS 21 uses reliability (confidence level) approach to account for variability. The FPS 21 design parameters utilized in our analyses are shown in the table below. Printouts of the FPS 21 results are presented in Appendix E.

FPS 21 Design Parameters

Confidence Level (DCM Table 5-4) 90% Initial Serviceability Index 4.5 Final Serviceability Index 2.5

Analysis Period (yr) (DCM Table 5-1) 20 20-yr Design ESALs (millions) 4.3

Design Modulus (ksi)

Dense-Graded Hit-Mix Asphalt (DCM Table 5-5) 500*

Flexible Base (DCM Table 5-5) 40 Lime Stabilized Subgrade (DCM Table 5-5) 20 Subgrade 20 Texas Triaxial Classification 4.1

* Full depth section was designed with a moduli of 250 ksi for the bottom 3 inches

RECOMMENDED PAVEMENT SECTIONS

Based on our findings and the results of our analyses, RKI recommends the following pavement options for this roadway.

Option 1 is the recommended pavement section that satisfies all FPS-21 standards and Williamson County DCM minimum pavement requirements.

Option 2 is a full-depth pavement option that should only be used in areas where short duration construction closures are permitted. The provided full depths sections satisfy FPS-21 standards including the Modified Triaxial Check; however, it should be understood that the full depth section will be at a higher risk of disturbance related to the subgrade performance characteristics (i.e. shrink/swell movements if founded on clay).

Option 3 is a temporary section for transition portions of the alignment where the new section will temporarily tie into the existing alignment. This section is proportioned for a design life on the order of 10 years, after which the upper 1 inch of existing asphalt should be milled, and a 2 in. overlay of Type “C” or “D” HMAC surface course should be placed, resulting in a section consisting of 6 inches of HMAC overlying 12 inches of flexible base, and 8 inches of lime stabilized subgrade. If cracks are present in the asphalt after initial milling, further milling is recommended until cracks are no longer observed.

Layer Description

Layer Thickness Option 1:

Recommended General Section

Option 2: Full Depth Asphalt

Option 3:

Transition Section

HMAC Surface Course, Type “C” or “D” HMAC Base Course, Type “B” Flexible Base Lime Treated Subgrade or Embankment Fill Combined Total

2.0 in.

4.0 in.

12.0 in.

8.0 in. .

26.0 in.

2.0 in.

9.0 in.

11.0 in.

2.0 in.

3.0 in.

12.0 in.

8.0 in. .

25.0 in.

Recommended Pavement Section - Driveways

We understand that driveways may be planned as part of the roadway reconstruction. The existing driveways are primarily unpaved gravel drives. We recommend that new drives be constructed in accordance with Figure 2-15 of the Williamson County DCM, which has been attached in Appendix F.

However, the subgrade is generally highly expansive and may be susceptible to seasonal loss in stiffness.

Thus, we recommend that consideration be given to removing the upper 6 inches of subgrade and replacing with compacted TxDOT Item 132 Type C1 embankment fill (see Embankment Fill) to provide a more uniform transition from the roadway.

PAVEMENT CONSTRUCTION CONSIDERATIONS

SUBGRADE PREPARATION

Any areas to support new pavements should be stripped of any existing pavement materials or fills and all vegetation and organic topsoil. The exposed subgrade should be proofrolled in order to locate weak, compressible zones prior to placement of the pavement system. A minimum of 5 passes of a fully-loaded dump truck or a similar heavily-loaded piece of construction equipment should be used for planning purposes.

Proofrolling operations should be observed by the Geotechnical Engineer or their representative to document subgrade condition and preparation. Weak or soft areas identified during proofrolling should be removed and replaced with suitable, compacted on-site soils, free of organics, oversized materials, and degradable or deleterious materials.

DRAINAGE CONSIDERATIONS

As with any soil-supported structure, the satisfactory performance of a pavement system is contingent on the provision of adequate surface and subsurface drainage. Insufficient drainage which allows saturation of the pavement subgrade and/or the supporting granular pavement materials will greatly reduce the performance and service life of the pavement systems.

Surface and subsurface drainage considerations crucial to the performance of pavements at this site include (but are not limited to) the following:

1) Any known natural or man-made subsurface seepage at the site which may occur at sufficiently shallow depths as to influence moisture contents within the subgrade should be intercepted by drainage ditches or below grade French drains.

2) Final site grading should eliminate isolated depressions adjacent to curbs which may allow surface water to pond and infiltrate into the underlying soils.

3) Pavement surfaces should be maintained to help reduce surface ponding and to provide rapid sealing of any developing cracks. These measures will help reduce infiltration of surface water downward through the pavement section.

EXCAVATION EQUIPMENT

Based on our findings, excavations and grading at this site may require removal of the upper weathered layers of the underlying rock formation. Therefore, the need for rock excavation equipment should be anticipated for grading at this site. Our boring logs are not intended for use in determining construction means and methods and may therefore be misleading if used for that purpose. We recommend that earth-work and utility contractors interested in bidding on the work perform their own tests in the form of test pits to determine the quantities of the different materials to be excavated, as well as the preferred excavation methods and equipment for this site.

SUBGRADE IMPROVEMENT

Lime Treated Subgrade

Lime treatment of the subgrade soils should be in accordance with the TxDOT Standard Specifications, Item 260. A sufficient quantity of hydrated lime should be mixed with the subgrade soils until the pH of the soil-lime mixture is at least 12.4. If any pH-lime series testing does not achieve a pH above 12.3, we recommend that the second lowest percentage of lime rather than the lowest be used as the optimum lime percentage for stabilization of the soil. Based on the testing completed for this study, we recommend that 8 percent lime by dry weight be used for estimating purposes. A maximum dry density of 100 pcf may be assumed for the near-surface native soils.

A quality assurance program should be implemented during construction to assist in reducing the risk of sulfate induced heaving and determining if changes in the optimum lime percentage are needed. The program should be used to identify if soluble sulfates and/or high organics exist in the exposed subgrade soils. Prior to implementation, the quality assurance program should be submitted to the geotechnical engineer for review, comment, and acceptance.

Lime-treated subgrade soils should be compacted to a minimum of 95 percent of the maximum density at a moisture content within the range of 1 percentage point below optimum moisture content to 2 percentage points above the optimum moisture content as determined by TxDOT, Tex-121-E.

Embankment Fill

Embankment fill materials for the pavement designs above should consist of Type C1 fill in accordance with TxDOT Item 132, modified per the Williamson County General Notes, dated August 26, 2019. Embankment fill material should consist of granular material free from vegetation or other objectionable materials and meeting the following specifications:

TxDOT/ WilCo Item

Description (Percent Retained-Sieve) LL

Max.

PI

Max.

PI

Min. 1-3/4” 7/8” #4 #40

132 Embankment (Density Control) (TY C1) 0-10 10-20 45-75 60-85 45 20 6

Select borrow fill should be placed in accordance with TxDOT Item 132 and compacted utilizing density and moisture control as described in the specification.

FLEXIBLE BASE COURSE

The flexible base course should conform to the requirements of TxDOT Item 247, modified per the Williamson County General Notes. The material should be crushed stone meeting the requirements of modified TxDOT Item No. 247, Type A, Grade 4, and meet the grading and testing requirements listed below:

Sieve Designation Cumulative Retained (%)

1-3/4” 0

7/8” 10-35

3/8” 30-65

No. 4 45-75

No. 40 70-90

No. 200 87-95

Other Requirements

Maximum Liquid Limit 35

Maximum Plasticity Index 10

Maximum Wet Ball Mill 40

Other Requirements

Maximum increase in passing #40 sieve from wet ball mill test 20

Triaxial Class I minimum test compressive strength at 3 psi lateral pressure 90 psi

Triaxial Class I minimum test compressive strength at 15 psi lateral pressure 175 psi

Flexible base course should be placed in lifts with a compacted thickness of 4 to 6 inches, compacted to a minimum of 100 percent of the maximum density as determined by Tex-113-E.

PRIME COAT

A prime coat should be placed on top of the flexible base course in accordance with TxDOT Item 310, modified per the Williamson County General Notes. Prime coat application rate is generally dependent upon the absorption rate of the flexible base and environmental conditions at the time of placement, and generally ranges from 0.1 to 0.3 gal/yd2.

The prime coat layer should be placed on the prepared flexible base as soon as possible. This will facilitate plugging the capillary voids in the flexible base surface to reduce migration of moisture and providing a water-resistant surface. The asphalt layer should be placed as soon as possible after the prime coat has been properly set/cured.

TACK COAT

An application of tack coat shall be applied in places where the asphalt will contact concrete curbs, manhole structures and/or where asphalt will be placed over an existing layer of asphalt in accordance with TxDOT Item 300, modified per the Williamson County General Notes.

The surface upon which the tack coat is to be placed shall be thoroughly cleaned and dry prior to tack coat placement; damp conditions may increase the time needed for tack coat to set. The tack coat shall be applied as directed by Engineer or designated representative. Recommended tack coat applications rates are presented in the TxDOT Pavement Manual, Table 6-1, and typically do not exceed 0.1 gal/yd2.

ASPHALTIC CONCRETE BASE COURSE

The asphaltic concrete base course should conform to TxDOT Standard Specifications, Item 340, Type B. The asphaltic concrete should be compacted to a minimum of 92 percent of the maximum theoretical specific gravity (Rice) of the mixture determined according to Test Method Tex-227-F. Pavement specimens, which shall be either cores or sections of asphaltic pavement, will be tested according to Test Method Tex-207-F.

The nuclear-density gauge or other methods which correlate satisfactorily with results obtained from project roadway specimens may be used when approved by the Engineer. Unless otherwise shown on the plans, the Contractor shall be responsible for obtaining the required roadway specimens at their expense and in a manner and at locations selected by the Engineer.

ASPHALTIC CONCRETE SURFACE COURSE

The asphaltic concrete surface course should conform to TxDOT Standard Specifications, Item 340, Type C or D. The asphaltic concrete should be compacted to a minimum of 92 percent of the maximum theoretical specific gravity (Rice) of the mixture determined according to Test Method Tex-227-F. Pavement specimens, which shall be either cores or sections of asphaltic pavement, will be tested according to Test Method Tex-207-F.

The nuclear-density gauge or other methods which correlate satisfactorily with results obtained from project roadway specimens may be used when approved by the Engineer. Unless otherwise shown on the plans, the Contractor shall be responsible for obtaining the required roadway specimens at their expense and in a manner and at locations selected by the Engineer.

PORTLAND CEMENT CONCRETE

The Portland cement concrete should have a minimum 28-day compressive strength of 4,000 psi. A liquid membrane-forming curing compound should be applied as soon as practical after broom finishing the concrete surface. The curing compound will help reduce the loss of water from the concrete. The reduction in the rapid loss in water will help reduce shrinkage cracking of the concrete.

MISCELLANEOUS PAVEMENT RELATED CONSIDERATIONS

Pavement Maintenance

Regular pavement maintenance is critical in maintaining pavement performance over a period of several years. All cracks that develop in asphalt pavements should be regularly sealed. Areas of moderate to severe fatigue cracking (also known as alligator cracking) should be sawcut and removed. The underlying base should be checked for contamination or loss of support and any insufficiencies fixed or removed and the entire area patched.

Construction Traffic

Construction traffic on prepared subgrade or granular base should be restricted as much as possible until the protective asphalt surface pavement is applied. Significant damage to the underlying layers resulting in weakening may occur if heavily loaded vehicles are allowed to use these areas.

CONSTRUCTION RELATED SERVICES

CONSTRUCTION MATERIALS TESTING AND OBSERVATION SERVICES

As presented in the attachment to this report, Important Information About Your Geotechnical Engineering Report, subsurface conditions can vary across a project site. The conditions described in this report are based on interpolations derived from a limited number of data points. Variations will be encountered during construction, and only the geotechnical design engineer will be able to determine if these conditions are different than those assumed for design.

Construction problems resulting from variations or anomalies in subsurface conditions are among the most prevalent on construction projects and often lead to delays, changes, cost overruns, and disputes. These variations and anomalies can best be addressed if the geotechnical engineer of record, RKCI is retained to perform construction observation and testing services during the construction of the project. This is because:

• RKCI has an intimate understanding of the geotechnical engineering report’s findings and recommendations. RKCI understands how the report should be interpreted and can provide such interpretations on site, on the client’s behalf.

• RKCI knows what subsurface conditions are anticipated at the site.

• RKCI is familiar with the goals of the owner and project design professionals, having worked with them in the development of the geotechnical work scope. This enables RKCI to suggest remedial measures (when needed) which help meet the owner’s and the design teams’ requirements.

• RKCI has a vested interest in client satisfaction, and thus assigns qualified personnel whose principal concern is client satisfaction. This concern is exhibited by the manner in which contractors’ work is tested, evaluated and reported, and in selection of alternative approaches when such may become necessary.

• RKCI cannot be held accountable for problems which result due to misinterpretation of our findings or recommendations when we are not on hand to provide the interpretation which is required.

BUDGETING FOR CONSTRUCTION TESTING

Appropriate budgets need to be developed for the required construction testing and observation activities.

At the appropriate time before construction, we advise that RKCI and the project designers meet and jointly develop the testing budgets, as well as review the testing specifications as it pertains to this project.

Once the construction testing budget and scope of work are finalized, we encourage a preconstruction meeting with the selected contractor to review the scope of work to make sure it is consistent with the construction means and methods proposed by the contractor. RKCI looks forward to the opportunity to provide continued support on this project and would welcome the opportunity to meet with the Project Team to develop both a scope and budget for these services.

ATTACHMENTS

Lake George town

Wil l iams Dr

W ill iams

D r

White Wing Golf

Club

Legacy Hills Golf Club

LEGEND

SITE LOCATION

SITE LOCATION MAP

RONALD REAGAN BLVD – SEGMENT D2

FROM EAST OF CR 245 TO SUN CITY BLVD

GEORGETOWN, WILLIAMSON COUNTY, TEXAS

PROJECT No.:

AAA24-036-00

DRAWN BY:

ISSUE DATE:

REVIEWED BY:

CHECKED BY:

BM

8/7/2024

RK

LC

NOTE: This Drawing is Provided for Illustration Only, May Not be to Scale and is Not Suitable for Design or Construction Purposes µ

Lake Georgetown Recreational

Area

Georgetown

UV487

UV970S I T E

FIGURE

1WILLIAMSON

COUNTY

0 10.5

Miles

World Navigation Map: County of Williamson, Texas Parks & Wildlife, CONANP, Esri, TomTom, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, EPA, NPS, USDA, USFWS World Street Map: County of Williamson, Texas Parks & Wildlife, CONANP, Esri, TomTom, Garmin, SafeGraph, FAO, METI/NASA, USGS, EPA, NPS, USFWS

TBPE Firm Number 3257

8100 Cameron Road, Suite B-150 Austin, Texas 78754

(512)339-1745 TEL

(512)339-6174 FAX

www.rkci.com

1 inch = 6,250 feet

WATER

Kwa

Kwa

Kec

Kec

Kgt

Kgt

Kgt

Kgr

Kec

Kec

Kec Kec

Kgt

Kgt Kgt

Kgt

Water

LEGEND

SITE LOCATION

GEOLOGIC UNIT

Kec: Edwards and Comanche Peak Limestones, undivided

Kgr: Glen Rose Limestone

Kgt: Georgetown Limestone

Kwa: Walnut Clay

Water

GEOLOGY MAP

RONALD REAGAN BLVD – SEGMENT D2

FROM EAST OF CR 245 TO SUN CITY BLVD

GEORGETOWN, WILLIAMSON COUNTY, TEXAS

PROJECT No.:

AAA24-036-00

DRAWN BY:

ISSUE DATE:

REVIEWED BY:

CHECKED BY:

BM

8/7/2024

RK

LC

NOTE: This Drawing is Provided for Illustration Only, May Not be to Scale and is Not Suitable for Design or Construction Purposes µ

FIGURE

2WILLIAMSON

COUNTY

0 10.5

Miles

World Imagery: Earthstar Geographics

TBPE Firm Number 3257

8100 Cameron Road, Suite B-150 Austin, Texas 78754

(512)339-1745 TEL

(512)339-6174 FAX

1 inch = 6,250 feet

Jenn ings Branch

Rd

C o u n ty

R o a d

Co da

Xin g

Jen ning s Bra nch

Rd

C o u n ty

R o a d

Ronald W Reagan Blvd

Jennings Branch

BS-1

BS-2

P-1 P-2 B-1 B-2

LEGEND

!? BORING

BULK SAMPLE

PROPOSED FRONTAGE

PROPOSED BRIDGE

PROPOSED RETAINING WALL

BORING LOCATION MAP

RONALD REAGAN BLVD – SEGMENT D2

FROM EAST OF CR 245 TO SUN CITY BLVD

GEORGETOWN, WILLIAMSON COUNTY, TEXAS

PROJECT No.:

AAA24-036-00

DRAWN BY:

ISSUE DATE:

REVIEWED BY:

CHECKED BY:

BM

8/7/2024

RK

LC

NOTE: This Drawing is Provided for Illustration Only, May Not be to Scale and is Not Suitable for Design or Construction Purposes µ

Ranch Road

SITE LOCATION MAP

FIGURE

3AWILLIAMSON

COUNTY

0 330165

FEET

World Street Map: County of Williamson, Texas Parks & Wildlife, CONANP, Esri, TomTom, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, EPA, NPS, USDA, USFWS World Imagery: Williamson County TX, Maxar Hybrid Reference Layer: Esri Community Maps Contributors, County of Williamson, Texas Parks & Wildlife, TBPE Firm Number 3257

8100 Cameron Road, Suite B-150 Austin, Texas 78754

(512)339-1745 TEL

(512)339-6174 FAX

1 inch = 330 feet

Jenn ings

Bran ch Rd

K itty

H a w k R d

Ki tty

Ha wk

Rd

Saratoga Ln

Saratoga Ln

S ilv e r S p u r B lv d

S ilv e r S p u r B lv d

B u n k e r H ill

L n

Bris tol Cv

W in te rh o rs e C v

L a fa y e tte

S t

Ronald W Reagan

Blvd

Y o rktow n St

Yo rk to wn

St

B enton

Ln

P-3

P-4

P-5

B-2

LEGEND

!? BORING

PROPOSED FRONTAGE

PROPOSED BRIDGE

PROPOSED RETAINING WALL

BORING LOCATION MAP

RONALD REAGAN BLVD – SEGMENT D2

FROM EAST OF CR 245 TO SUN CITY BLVD

GEORGETOWN, WILLIAMSON COUNTY, TEXAS

PROJECT No.:

AAA24-036-00

DRAWN BY:

ISSUE DATE:

REVIEWED BY:

CHECKED BY:

BM

8/7/2024

RK

LC

NOTE: This Drawing is Provided for Illustration Only, May Not be to Scale and is Not Suitable for Design or Construction Purposes µ

Ranch Road

SITE LOCATION MAP

FIGURE

3BWILLIAMSON

COUNTY

0 330165

FEET

World Street Map: County of Williamson, Texas Parks & Wildlife, CONANP, Esri, TomTom, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, EPA, NPS, USDA, USFWS World Imagery: Williamson County TX, Maxar Hybrid Reference Layer: Esri Community Maps Contributors, County of Williamson, Texas Parks & Wildlife, TBPE Firm Number 3257

8100 Cameron Road, Suite B-150 Austin, Texas 78754

(512)339-1745 TEL

(512)339-6174 FAX

Yo rk to wn

S t

Ron ald

W Rea gan

Blv d

Shiloh Ln

Ki tty

Ha w k

R d

Yo rk to wn

St

B enton

Ln

Fletch er S t

RW-1

RW-2

RW-3

RW-4

P-5

P-6

P-7

LEGEND

!? BORING

PROPOSED FRONTAGE

PROPOSED BRIDGE

PROPOSED RETAINING WALL

BORING LOCATION MAP

RONALD REAGAN BLVD – SEGMENT D2

FROM EAST OF CR 245 TO SUN CITY BLVD

GEORGETOWN, WILLIAMSON COUNTY, TEXAS

PROJECT No.:

AAA24-036-00

DRAWN BY:

ISSUE DATE:

REVIEWED BY:

CHECKED BY:

BM

8/7/2024

RK

LC

NOTE: This Drawing is Provided for Illustration Only, May Not be to Scale and is Not Suitable for Design or Construction Purposes µ

Ranch Road

SITE LOCATION MAP

FIGURE

3CWILLIAMSON

COUNTY

0 330165

FEET

World Street Map: County of Williamson, Texas Parks & Wildlife, CONANP, Esri, TomTom, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, EPA, NPS, USDA, USFWS World Imagery: Williamson County TX, Maxar Hybrid Reference Layer: Esri Community Maps Contributors, County of Williamson, Texas Parks & Wildlife, TBPE Firm Number 3257

8100 Cameron Road, Suite B-150 Austin, Texas 78754

(512)339-1745 TEL

(512)339-6174 FAX

S ilver

S pur

B lvd

S ilver

S pur

B lvd

Ma rtin gal e St

B e llo

C ir

Ron ald

W Rea gan

Blv d

Ron ald W Reag an Blvd

M ar t i n g a le

S t

Bello Cir

Tall Riders Dr

M a rtin

C re e k L nS trik e r L n

P-8

P-9

P-10

LEGEND

!? BORING

PROPOSED FRONTAGE

PROPOSED BRIDGE

PROPOSED RETAINING WALL

BORING LOCATION MAP

RONALD REAGAN BLVD – SEGMENT D2

FROM EAST OF CR 245 TO SUN CITY BLVD

GEORGETOWN, WILLIAMSON COUNTY, TEXAS

PROJECT No.:

AAA24-036-00

DRAWN BY:

ISSUE DATE:

REVIEWED BY:

CHECKED BY:

BM

8/7/2024

RK

LC

NOTE: This Drawing is Provided for Illustration Only, May Not be to Scale and is Not Suitable for Design or Construction Purposes µ

Ranch Road

SITE LOCATION MAP

FIGURE

3DWILLIAMSON

COUNTY

0 330165

FEET

World Street Map: County of Williamson, Texas Parks & Wildlife, CONANP, Esri, TomTom, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, EPA, NPS, USDA, USFWS World Imagery: Williamson County TX, Maxar Hybrid Reference Layer: Esri Community Maps Contributors, County of Williamson, Texas Parks & Wildlife, TBPE Firm Number 3257

8100 Cameron Road, Suite B-150 Austin, Texas 78754

(512)339-1745 TEL

(512)339-6174 FAX

Ron ald W Reag an Blvd

Pricillas Well

Ronald W Reagan Blvd

C o a c h s m ith

S t

R id g e to p V is ta

D r

Ty co on

Ln

Ban dana

Ln

P-11

P-12

P-13

LEGEND

!? BORING

PROPOSED FRONTAGE

PROPOSED BRIDGE

PROPOSED RETAINING WALL

BORING LOCATION MAP

RONALD REAGAN BLVD – SEGMENT D2

FROM EAST OF CR 245 TO SUN CITY BLVD

GEORGETOWN, WILLIAMSON COUNTY, TEXAS

PROJECT No.:

AAA24-036-00

DRAWN BY:

ISSUE DATE:

REVIEWED BY:

CHECKED BY:

BM

8/7/2024

RK

LC

NOTE: This Drawing is Provided for Illustration Only, May Not be to Scale and is Not Suitable for Design or Construction Purposes µ

Ranch Road

SITE LOCATION MAP

FIGURE

3EWILLIAMSON

COUNTY

0 330165

FEET

World Street Map: County of Williamson, Texas Parks & Wildlife, CONANP, Esri, TomTom, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, EPA, NPS, USDA, USFWS World Imagery: Williamson County TX, Maxar Hybrid Reference Layer: Esri Community Maps Contributors, County of Williamson, Texas Parks & Wildlife, TBPE Firm Number 3257

8100 Cameron Road, Suite B-150 Austin, Texas 78754

(512)339-1745 TEL

(512)339-6174 FAX

!?Ronald W Reagan Blvd

S a lt C re e k L n

R id g e to p V is ta

D r

B e rr y C re ek

Ronald W Reagan Blvd

Sun City

B lvd

M o n u m e n t H ill

T rl

M onum ent H ill Trl

S a n d y C re ek

Trl

Sal t C…