Material Selection and Pavement Design – Accelerated ......Material Selection and Pavement Design...

Short Course 2019 October 15, 2019

Material Selection and Pavement Design –Accelerated ConstructionS. Lacy Peters, P.E. – TxDOT Atlanta District

October 15, 2019


Table of contents

4-5

6-8

9-12

13-18

19-24

3

25-26

What is Accelerated Construction?

Accelerated Construction Guidelines – Key Points

Accelerated Construction Guidelines – Pavement Design

Accelerated Construction Guidelines – Construction Considerations

Foamed Asphalt Base Project – Cass County; FM 3129

Foamed Asphalt Base Project – Harrison County; FM 9

Questions

1

2

2

3

4

5

6

7


What is Accelerated Construction?

Accelerated construction entails all the aspects of getting a project built rapidly including project selection, planning, contracting, design, traffic control, construction methods, publicity, and contingences.

The barriers as well as the opportunities associated with accelerated construction operations include materials availability and delivery, equipment capabilities and limitations, quality control/quality assurance (QC/QA) procedures, workforce availability, economic incentives, public information, and safety considerations among others.

Accelerated Construction Guidelines – December 2017

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4

Emergency versus Planned Accelerated Construction

Guidelines for TxDOT Projects

– Project Selection and Planning

– Contracting Methods

– Design

– Contractor Selection

– Involvement of Contractor

– Construction Considerations

References



5

Design

– General Considerations

– Geometric Design

– Bridge Design

– Drainage Design

– Pavement Design

– Roadside Safety Design

– Traffic Control and Job Sequencing

– Project Duration


Accelerated Construction Guidelines - Pavement Design

6

Pavement Design

– Pavement Recycling

– Stabilization of Subgrade/Base Items

– Reconstruction of Old Concrete Pavement

– Special Considerations

• Widening Projects

• Curb and Gutter Section

The number of materials that need to be placed in a pavement section should be minimized. The use of stabilized layers often reduces the number of materials that are required.

Alternatives should be evaluated from a performance and constructability point of view.



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Pavement Design (continued)

– This section references the Pavement Design Guide, which is now called the Pavement Manual and can be found on the MNT website.

– In place recycling avoids the removal and replacement of materials from the job site.

– The use of asphalt stabilized base materials rather than flexible base will reduce the overall thickness of the pavement layer. Asphalt base can be placed at a higher production rate than flexible base materials.

• The length of time to cure some materials prior to placing subsequent layers should be evaluated on a project-by-project basis.

– Rigid pavement reconstruction techniques: bonded concrete overlay, unbondedconcrete overlay, cracking and seating or rubblizing the existing pavement and then overlaying with ACP, or an ACP overlay of the existing concrete pavement.



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Pavement Design (continued)

– All the regular issues with pavement design still exist.

– The pavement design phase should take into account those materials that are needed and even those that are most likely to be utilized in your area. If there are items/sources that are not typically used, thoughts even down to the need for qualified technicians to inspect and test should be noted.

– The Pavement Manual should be consulted for material selection and design of accelerated options.

– REMEMBER: Accelerated Construction is NOT intended to Accelerate Maintenance!!!!!



9

Construction Considerations

– Work Plan and Work Sequence

– Workforce

– Work Space

– Equipment

– Quality Control/Quality Assurance/ Acceptance

– Information Exchange



10

Construction Considerations – (continued)

– Accelerated construction is not possible without a carefully crafted plan prior to construction and one that is adjusted continuously and at key intervals during the construction process.

– Decisions need to be made at the lowest workforce level on the project as possible.

– Securing right-of-way to provide space should be considered by TxDOT and made available to all contractors.

– The work plan should allow for equipment downtime for maintenance and repair.

• Redundant critical equipment should be on hand

• The development of equipment should continue so that the capabilities to move material quickly from one location to another can be improved.



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Construction Considerations – (continued)

– QC/QA

• QUALITY CANNOT BE SACRIFICED ON ACCELERATED CONSTRUCTION PROJECTS!

• Decisions related to materials acceptance need to be made in a timely fashion.

• Technicians used for sampling and testing should be certified, and laboratories in which testing is performed should be accredited.

– Regularly scheduled meeting should be established at the initiation of the project. Additional meetings should be held when necessary. Key Contractor and TxDOT personnel should be expected to attend.


Accelerated Construction Guidelines – TAKE AWAY

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QUALITY CANNOT BE SACRIFICED ON ACCELERATED CONSTRUCTION PROJECTS!

DO NOT ACCELERATE CONSTRUCTION IN A WAY THAT WILL RESULT IN ACCELERATED MAINTENANCE!!!


Asphalt Foamed Base Project – Cass County; FM 3129

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Location Map and Typical Section


Foamed Asphalt Base Project – Cass County; FM 3129

14

Mixture Design provided by MTD

– Richard Izzo, Soils and Aggregates Section Director

– Materials and Tests Division

– (512) 506-5907


Foamed Asphalt Base Project – Cass County; FM 3129; Process

15


Foamed Asphalt Base Project – Cass County; FM 3129; TTI Evaluation

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TTI Evaluation and Conclusions Provided by Stephen Sebesta

– [email protected]


Foamed Asphalt Base Project – Cass County; FM 3129; TTI Evaluation

17

Conclusions included:

– Foamed asphalt base modulus on average is within the expected range of 200 – 300 ksi

– Section is holding up well to trafficking, even without the one-course, with almost no raveling

– No major items of concern at this time• SB OWP by DPS check station may be monitored; this is the zone of

highest deflection observed on the work completed to date• ~ STA 405+91 to 387+86

– Techniques to mitigate occurrences of edge instability at early trafficking appeared effective• Future projects should consider shoulder width in design stage,

particularly if heavy truck traffic must be allowed same day• Future FDR work should particularly be careful of excessive moisture at

time of treatment especially when early traffic is required


Foamed Asphalt Base Project – Cass County; FM 3129; Current Status

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Location Map and Typical Section



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Mixture Design provided by MTD

– Richard Izzo, Soils and Aggregates Section Director

– Materials and Tests Division

– (512) 506-5907


Foamed Asphalt Base Project – Harrison County; FM 9; Process

21


Foamed Asphalt Base Project – Harrison County; FM 9; TTI Evaluation

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TTI Evaluation and Conclusions Provided by Stephen Sebesta

– [email protected]


Foamed Asphalt Base Project – Harrison County; FM 9; TTI Evaluation

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Conclusions included:

– FDR base modulus with foamed asphalt on average exceeds the assumed 150 ksi from design• AVG was 175 ksi• Current recommendation for foamed asphalt layer design is 200 ksi.

This value was not met on FM9.– The subgrade modulus AVG of ~ 13 ksi is significantly higher than the

assumed value in design. Any observed high deflections should not be caused by subgrade support.

– SB IWP was poorest result. 15% of data in SB IWP had deflections exceeding the threshold from design.

– Should monitor particularly the last 2 mi. in SB direction, and retest project in ~ 3 – 6 months.• Evaluate if the results have changed and evaluate if local adjustment to

FDR layer modulus with foamed asphalt is required.


Foamed Asphalt Base Project – Harrison County; FM 9; Current Status

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TxDOT Districts – Atlanta

25

Dallam Sherman Hansford Ochiltree Lipscomb

Hartley Moore Roberts Hemphill

Oldham Potter Carson Gray Wheeler

Deaf Smith Randall Armstrong DonleyCollings-worth

Parmer Castro Swisher Briscoe Hall

Bailey Lamb Hale Floyd Motley

Dickens King KnoxHockleyLubbock

Crosby

GarzaLynnTerryYoakum

Gaines Dawson Borden Scurry Fisher Jones

Kent Stonewall HaskellThrock-morton

Baylor

Wilbarger Wichita

WICHITAFALLS

Clay

Archer

YoungJack

Howard Mitchell NolanTaylor

Callahan Eastland

Glasscock Sterling Coke Runnels

ReaganIrion

Cooke Grayson Fannin

Lamar

Delta

Red River

PARISBowie

Wise Denton CollinHunt Hopkins

RainsWood Upshur

Marion

Cass

Titus

Mor

ris

Camp

ATLANTA

HarrisonSmith

VanZandt

Henderson TYLER

Rusk Panola

AndersonCherokee

Freestone

DallasDALLAS

Rockwall

Palo Pinto

Parker Tarrant

Shelby

SabineHouston LUFKIN

Angelina

TylerPolk

Trinity

Jasp

er

New

ton

SanJacinto

Walker

Leon

Navarro

Ellis

Hardin

FORTWORTH

Erath

Hood Johnson

Hill

BosqueMc

LennanHamilton

Coryell

Bell

Falls

WACO

RobertsonMadison

Milam

Brazos

Grim

es

Burleson

BRYAN

WashingtonLee

Austin

FayetteHarris

Montgomery Liberty

BEAUMONT

Orange

Jefferson

ChambersHOUSTON

FortBend

Brazoria

Matagorda

Wharton

Colorado

LavacaGonzales

Dewitt

YOAKUM

Jackson

Victoria

CalhounGoliad

Bee Refugio

Karnes

LiveOak

JimWells

SanPatricio

NuecesCORPUSCHRISTI

Kleberg

Kenedy

WillacyHidalgo

BrooksJim

HoggZapata

Starr

PHARR

Duval

Webb

LAREDO

La SalleDimmit

Zavala Frio Atascosa

McMullen

Guadalupe

Wilson

Bexar

MedinaUvalde

Real Bandera

KerrKendall

Gillespie Blanco

Kinney

SANANTONIO

Edwards

Sutton Kimble

Mason LlanoBurnet

Williamson

Travis

AUSTINBastrop

Hays

CaldwellComal

Brown Comanche

BROWNWOOD

Coleman

Mills

McCulloch

San Saba Lampasas

Concho

Menard

SANANGELO

Schleicher

TomGreen

Andrews Martin

Midland

Pecos

Ector

CraneWard

WinklerLoving

Crockett

Val Verde

Upton

Terrell

ReevesCulberson

Jeff Davis

BrewsterPresidio

Hudspeth

El PasoEL PASO

ODESSA

LUBBOCK

AMARILLO

ABILENE

Cottle Foard

CHILDRESS

Fran

klin

Cameron


Questions

S. Lacy Peters, P.E. Materials and Pavement Engineer

Texas Department of Transportation Atlanta District

[email protected] 903-799-1330

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