RM 652 - Texas A&M University

2020 Virtual Transportation Short Course October 14, 2020

RM 652Kevin Stafford, Ph.D.

Dept. of Geology, SFASU

Sheetal Patel, P.E.TXDOT – El Paso District

October 14, 2020


Project Location - RM 652

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Culberson County, Texas RM 652 Project Area


Common Problems

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1. Karst Voids and Cavities within and adjacent to Right-of-Way

2. Voids in Base Layer

3. Voids in Subgrade

4. Dynamic Hydrogeology

5. Poor Surface Drainage

6. Low Water Crossing

7. Insufficient Cross Drainage Structures

8. Dikes Constructed


Geologic Characterization – RM 652

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Ground Penetrating Radar

Geologic MappingLiDAR Analyses

Karst AnalysesElectrical Resistivity Imaging

Field Assessment Methods


Karst – RM 652

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HypogeneEpigene Phreatic

Epigene Vadose


Karst– RM 652

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Hydrogeology – RM 652

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Google Earth

Enlarged Area Above


Soils – RM 652

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Natural Geohazards– RM 652

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Solution Caves Fractures & Breccia Leached Bedrock Suffosion Caves


Anthropogenic Geohazards– RM 652

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Utility Cables Concrete Structures Voids in Base Variable Subgrade


Geohazard Characterization – RM 652

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Geohazard Characterization – RM 652

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Other Challenge – RM 652 an Energy Sector Corridor

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Delaware Basin

Significant increase of Energy Sector Activity since 2013

Truck Traffic increase

Roadway damage

Heavily traveled by sand and water trucks as well as oilfield equipment -Permian Basin Freight Plan


RM 652 Corridor Scheduled Projects

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History – RM 652

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Length: 34 miles

Constructed in 3 phases

– 1st Phase: 9.5 miles (1950)

– 2nd Phase: 10 miles (1959)

– 3rd Phase: 14.5 miles (1961)

Existing Typical Section

– 2” Seal Coats

– 6” Flexible Base -From Pits in the area

– Subgrade – Variable Soil Types (Gypsum)


RM 652 – As-built Review

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Roadway constructed directly over and near existing Sinkholes

Dikes constructed throughout the length of the highway


RM 652 – Existing Roadway Conditions

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Very High Gypsum content in base and subgrade materials– Making both highly moisture susceptible

Water getting to moisture susceptible base– Main cause of damage

Lack of adequate drainage– Inadequate Ditches– Several Low Water Crossings

Overall Pavement Condition – Poor

– Extensively Cracked Surface – Rutting Failures– Poor Ride Quality

High number Driveways –Safety issue


TTI: Corridor Analysis and Pavement Evaluation

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Gypsum content of subgrade


Soil Investigation

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Sampling Sites

Lab Data


Nondestructive Testing

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Observations from GPR (location and extent of full depth patches)

Ground Penetrating Radar (GPR) Falling weight Deflectometer (FWD) Total Pavement Acceptance Device (TPAD)

Full depth patches with 10+ inches


Nondestructive Testing

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FWD maximum deflection plot:• High deflections are attributed to moisture entering and

softening the pavement layers

MODULUS 7 Output of Subgrade Moduli for Phase 2: • Extremely high variability• Highlighted area has a very weak subgrade• 4.2 ksi was used in FPS 21 design


Destructive Testing

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Wetter materials 12 to 48 inchesAt 48 inches Tan Fat Clay No Voids down to 6 ft.High deflections =Clay subgrade

Uniform low PI material with depth

High Deflection Area Low Deflection Area


Full Depth Reclamation Lab Studies

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Stabilizer % Cement

Dry IDT(psi)

Wet IDT(psi)

24 hr. soak

Wet IDT(psi)

21 day soak4% Fly Ash 0 15.6 6.7 138% Fly Ash 0 27.1 16.8 28

2.6% Emulsion 1 75.1 46.6 36.23.0% Cement 3 65.9 53.3 55.52.6% Foam 1 68.0 36.2 22.2

Criteria > 50 >30

Test Results: Site 2 - TRM 160


Traffic Data: Weigh in Motion (WIM)

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Proposed Pavement Design

Time to First Overlay 13 to 15 years

Time to First Overlay 20 years

Emulsion Treated Base Design(Phase 1 & 2)

• 1” TOM C• Underseal• 8” ETB

• 1” TOM C• Underseal• 10” ETB

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Segment 1A: Full Depth Rehabilitation (In Construction)

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CSJ 2451-02-012

– Let in Feb-2019: $22.48M

– 12’ Lane with 10’ Shoulder

– Improved designed Drainage and Driveways

– TOM C + Underseal

– 10” Emulsion Treated Base (SS 3003: Road-Mixed)

– Removal of all existing material

– All New Base Material

– Sulfate Content Restriction in Base, Embankment, and Water to be used

Karst features uncovered during construction


Segment 2B: Full Depth Rehabilitation (In Construction)

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CSJ 1314-02-014

– Let in Jan - 2020: $17.23 M

– 12’ Lane with 10’ Shoulder

– TOM C + Underseal

– Improved designed Drainage and Driveways

– 10” Emulsion Treated Base: New OTU SS 3083 - Emulsified Asphalt Base (Plant-Mixed)

– Removal of all existing material

– All New Base Material

– Sulfate Content Restriction in Base, Embankment, and Water to be used

Project Specific Details

– Karst Feature Repairs Detail

– Gypsum Lined Ditches (in Low Velocity Drainage Area)

– Asphalt Lined Ditches (Low Permeability Media)

– Use of Geogrid (to minimize risk)


Full Depth Rehabilitation: Road-Mixed Vs Plant Mixed

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Road-Mixed Emulsion Treated Base– Mix Design (1% Cement +2.3% High Yield

Emulsion)

– $/SY (Treatment): $3.30

– Total $/SY (Material +Treatment): $44.01

Plant-Mixed Emulsion Treated Base– Mix Design (1% Cement +2.6 % High Yield

Emulsion)

– Total $/SY (Material +Treatment): $50.00

– First Plant-Mix Emulsified Asphalt Base Project in the State

– Allowed Use of Paver or Spreader

– Uniformly coated particles

– Homogenous mix

– Able to place ETB directly onto Geogrid


Segment 3 : Full Depth Rehabilitation

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Segment 3: Scheduled to Let in Nov - 2020– 12’ Lane with 10’ Shoulder– SP-C + Underseal– 10” Foamed Asphalt Treatment – Improved designed Drainage and Driveways– Removal of all existing material– All New Base Material– Sulfate Content Restriction in Base, Embankment,

and Water to be used

Project Specific Details – Karst Feature Details– Gypsum Lined Ditches (in Low Velocity Drainage

Area)– Asphalt Lined Ditches (Low Permeability Media)– Use of Geogrid (to minimize risk)


Segment 2A and 1B : Full Depth Rehabilitation

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Segment 2B and 1B: Scheduled to Let in Nov - 2023– 12’ Lane with 10’ Shoulder– SP-C + Underseal– 10” Foamed Asphalt Treatment – Improved designed Drainage and Driveways– Removal of all existing material– All New Base Material– Sulfate Content Restriction in Base, Embankment, and

Water to be used

Project Specific Details – Karst Feature Details– Gypsum Lined Ditches (in Low Velocity Drainage Area)– Asphalt Lined Ditches (Low Permeability Media)– Use of Geogrid (to minimize risk)


Thank you

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Texas A&M Transportation Institute (TTI)

Stephen F. Austin State University (SFA)

TxDOT – Materials & Tests Division

TxDOT – Maintenance Division

Design Consultants– Omega

– Entech Civil Engineers

– RHS (Siegfried Engineering & Construction, LLC)

– RODS Survey


Questions

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Documents

RM 652 - Texas A&M University