Mark B. Snyder, Ph.D., P.E., Engineering ConsultantBridgeville, Pennsylvania

Prepared for presentation at the 2008 Minnesota Concrete ConferenceContinuing Education and Conference Center, St. Paul, MN February 14, 2008

FHWA-Sponsored Research

University of MinnesotaERES Consultants, Inc.

Physical and Mechanical PropertiesPhysical and Mechanical Properties of Recycled PCC Aggregate Concreteof Recycled PCC Aggregate Concrete

1993 - 19991993 - 1999

RCA has been used widely with varying results.

Most common failures:◦deteriorated midpanel cracks◦loss of load transfer

Determine causes of pavement distress related to use of RCA in PCC pavements.

Develop practical, reliable guidelines for RCA concrete mix designs.

Identify pavement designs for which RCA concrete is appropriate.

Extensive Literature ReviewField Testing and EvaluationLaboratory Testing and Evaluation

Distress (cracked, uncracked, other)JRCP, JPCP (CRCP?)Available control sectionRange of climates, trafficUniform traffic flowNo substructures

Original 1993 Study:9 Projects

5 RCA + Control 4 RCA Only

2 Single Sections1 Varying LT1 Varying Performance

16 Sections Total

Category Location Climatic Region

1994 Age, Yrs

Control Section

2 Way ADT, veh/day

Pavement Type (% long.

reinf.)

Joint Spacing, ft

Dowel Diam., in

1(Good)

CT 1, I-84 near Hartford

W-F 14 yes 56,000 9-in JRCP(0.10 %)

40 1.5 (I-beam)

MN 1, I-94 near Brandon

W-FTransition

6 yes 8,170 11-in JRCP(0.06 %)

27 1.25

KS 1, K-7Johnson County

W-F 9 yes 7,310 9-in JPCP(n/a)

15 None

2(Structural Problems)

MN 4, US52near Zumbrota

W-F 10 yes 7,820 9-in JRCP(0.06 %)

27 1.0

MN 2, I-90 Beaver Creek

W-FTransition

10 no 1,670 9-in JRCP(0.06 %)

27 1.0

WI 1, I-94 near Menomonie

W-F 10 no 8,170 11-in JPCP(n/a)

12-13-19-18 None / 1.375

3(Other

Distresses)

MN 3, US59 near Worthington

W-FTransition

14 no 2,150 8-in JPCP(n/a)

13-16-14-19 None

WI 2, I-90 near Beloit

W-F 8 no 22,622 10-in CRCP(0.67 %)

n/a n/a

WY 1, I-80 near Pine Bluffs

D-F 9 / 10 yes 4,410 (RCA)4,280 (Con.)

10-in JPCP(n/a)

14-16-13-12 None

Condition Survey Drainage Survey FWD Coring◦Midpanel◦Joints◦Cracks

Crack, Joint Width Faulting PSR Photolog

CompressionSplit TensionStatic EDynamic E

Surface Texture◦Sand Patch◦Profilometer

Freeze-ThawLinear TraversePetrography

FHWA-Sponsored Research

University of New HampshireRecycled Materials Resource Center

Performance of Concrete PavementsPerformance of Concrete PavementsContaining Recycled Concrete AggregateContaining Recycled Concrete Aggregate

20062006(Update of previous study)(Update of previous study)

Revisit 1994 study sections to obtain longer-term materials and performance data.

Include additional test sites to expand inference base of original study.

Update conclusions from 1994 study.

Category Location Climatic Region

2006 Age, Yrs

Control Section

2 Way ADT, veh/day

Pavement Type (% long.

reinf.)

Joint Spacing, ft

Dowel Diam., in

3(Other

Distresses)

IA 1, US 75 near Rock

Rapids

W-F 30 no 2,150 9-in JPCP(n/a)

13-16-14-19 None

IL 1, I-57 near Effingham

W-F 20 no 4,410 (RCA)4,280 (Con.)

10-in CRCP(n/a)

n/a n/a

Condition Survey Drainage Survey Coring◦Midpanel◦Joints◦Cracks

[No FWD]

Crack, Joint Width Faulting PSR Photolog

CompressionSplit TensionStatic E

Modified ASTM C 1293 (ASR)

ASTM C 856 (Uranyl Acetate)

Volumeteric Surface Texture

Petrography

Project Review and Performance Summary(Age 18 yrs)

Recycled

Recycled

Recycled

Control

Control

Control

MN 1-1 (Recycled) MN 1-2 (Control)Sturtevant M.S. Thesis - 2007

Test and ValueMN 1-1

(Recycled)MN 1-2

(Control)

Transverse Joint Spalling,% Joints

76 54

Avg. Faulting between Panels, mm 0.9 1.3

Longitudinal Cracking, m/km 0 0

Transverse Cracking, % Slabs 31 0

Deteriorated TransverseCracks/km

35 0

Total Transverse Cracks/km 38 0

PSR 3.7 4.0

IRI 1.1 0.9

Tensile Strength, MPa 2.9 3.3

Compressive Strength, MPa 44.9 59.0

Uranyal Acetate Reaction None None

Young’s Modulus, GPa 28.9 33.4

•Comparable performances in 1994•Mortar Content

•77% RCA•66% Control

•Similar Thermal Coefficients in 1994•11.9/Co RCA•11.9/Co Control

•~25% increase in Young’s modulus since 1994•Inconsistent strength trends since 1994•RCA strength consistently lower, but adequate

Project Review and Performance Summary(Age 22 yrs)

I-90 EB

I-90 EB

I-90 EB

I-90 WB

I-90 WB

I-90 WB

MN 2-1 (Recycled) MN 2-2 (Recycled)Sturtevant M.S. Thesis - 2007

Test and ValueMN 2-1(RCA 1)

MN 2-2(RCA 2)

Transverse Joint Spalling,% Joints

46 66

Avg. Faulting between Panels, mm 0.6 0.5

Avg. Joint Width, mm 12 13

Longitudinal Cracking, m/km 26 0

Transverse Cracking, % Slabs 90 92

Deteriorated TransverseCracks/km

112 112

Total Transverse Cracks/km 112 115

PSR 4.0 3.8

IRI 0.9 1.0

Tensile Strength, MPa 3.7 2.8

Compressive Strength, MPa 49.5 64.1

Uranyal Acetate Reaction Low None

Modified ASTM 1293, % Expansion at 108 Days

0.054 n/a

Young’s Modulus, GPa n/a 31.1

Project Summary and Performance Review(Age 26 yrs)

MN 59

MN 59

MN 59

MN 59

MN 3-1 (Recycled)Sturtevant M.S. Thesis - 2007

Test and ValueMN 3(1994)

MN 3(2006)

Transverse Joint Spalling,% Joints

71 89

Transverse Joint Seal Damage,% Joints

76 0

D-cracking, % Slabs 0 0

Avg. Faulting between Panels, mm 6.1 0.3

Avg. Joint Width, mm 20 18

Longitudinal Cracking, m/km 19 0

Transverse Cracking, % Slabs 2 12

Deteriorated TransverseCracks/km

3 26

Total Transverse Cracks/km 3 26

PSR 3.0 4.3

IRI 1.7 0.6

Tensile Strength, MPa 4.1 3.7

Compressive Strength, MPa 44.1 52.4

42

Recycled section only

Constructed in 1980

Rehabilitated after 1994

Diamond grinding

Retrofitting of transverse dowel bars

PSR = 4.3 (3.0 in 1994)

Avg. faulting between panels = 0.3 mm (6.1 mm in 1994)

No recurring D-cracking

ASR found during uranyl acetate testing

Moderate expansion in Modified ASTM 1293 testing

No ASR related distress found in field

Project Summary and Performance Review(Age – 22 yrs)

MN 4-1 (Recycled) MN 4-2 (Control)Sturtevant M.S. Thesis - 2007

Test and ValueMN 4-1

(Recycled)MN 4-2

(Control)Transverse Joint Spalling,% Joints

81 100

D-cracking, % Slabs 0 0Pumping, % Slabs 0 0Slab/Patch Deterioration,% Slabs

3 0

Avg. Faulting between Panels, mm 0.9 0.9

Avg. Joint Width, mm 12 11Longitudinal Cracking, m/km 17 0Transverse Cracking, % Slabs 92 24Deteriorated TransverseCracks/km

125 26

Total Transverse Cracks/km 131 29PSR 3.0 3.8IRI 1.7 1.0Tensile Strength, MPa 2.4 2.5Compressive Strength, MPa 45.1 50.7Uranyal Acetate Reaction None NoneYoung’s Modulus, GPa 30.0 43.4Average VSTR (cm3/cm2) 0.2902 0.3264

•In 1994, performances were comparable, but RCA section was showing signs of imminent deterioration•Foundation Stiffness (backcalculated) 30% lower for RCA section•Aggregate Top Size

•1.0-in RCA•1.5-in Control

•Mortar Content•84% RCA (higher shrinkage?)•52% Control

•Similar Thermal Coefficients in 1994•12.4/Co RCA•11.9/Co Control

•~10% increase in compressive strength since 1994

47

Recycled and control sections rehabilitated after 1994

Diamond grinding

Retrofitting of transverse dowel bars

Field survey showed recycled did not perform as well as control

Recycled had higher mortar content (74% vs. 52%)

Formation of shrinkage cracks early on

Figure 58: Recycled Pavement Distresses (Avg. % Change from 1994 to 2006)

-40%

-20%

0%

20%

40%

60%

80%

100%

T. J

. Spa

lling

T. J

.Sea

l Dam

age

L. J

. Sea

l D

amag

e

D-c

rack

ing

Pum

ping

Sla

b/P

atch

Det

erio

ratio

n

L. to

S. D

rop

off

L. to

S. S

epar

atio

n

Fau

lting

Join

t Wid

th

L. C

rack

ing

T. C

rack

ing

Det

erio

rate

d T

.C

rack

s

Tot

al T

. Cra

cks

PS

R IRI

% C

han

ge

(94

to 0

6)

All

Rehabilited

Not Rehabilitated

Sturtevant M.S. Thesis - 2007

Figure 59: Control Pavement Distresses (Avg. % Change from 1994 to 2006)

-40%

-20%

0%

20%

40%

60%

80%

100%

T. J

. Spa

lling

T. J

.Sea

l Dam

age

L. J

. Sea

l D

amag

e

D-c

rack

ing

Pum

ping

Sla

b/P

atch

Det

erio

ratio

n

L. to

S. D

rop

off

L. to

S. S

epar

atio

n

Fau

lting

Join

t Wid

th

L. C

rack

ing

T. C

rack

ing

Det

erio

rate

d T

.C

rack

s

Tot

al T

. Cra

cks

PS

R IRI

% C

han

ge

(94

to 0

6)

All

Rehabilited

Not Rehabilitated

Sturtevant M.S. Thesis - 2007

•Need to treat RCA as “engineered material” and modify mix and structural designs accordingly

•Reduce w/c•ASR mitigation•Reduced panel lengths•Etc.

•Mortar contents generally higher for RCA•Reclaimed mortar content varied with virgin aggregate type, crushing process•RCA, conventional aggregate PCC performance comparable when natural CA types and quantities are similar•Higher mortar contents had more distress – need to control reclaimed mortar content

Granular Base Sections◦CT1-1, 16.6, 66%◦CT1-2, 15.2, 93%◦MN1-1, 7.3, 1%◦MN1-2, 7.3, 0%◦MN2-1, 8.2, 84%◦MN4-1, 7.8, 88%◦MN4-2, 8.2, 22%

◦WI1-1, 4.4, 8%◦WI1-2, 4.6, 2%◦WY1-1, 4.3, 0%◦WY1-2, 4.3, 0%

Stabilized Base Sections◦KS1-1, 5.5, 0%◦KS1-2, 5.5, 0%◦MN3-1, 5.0, 2%

•Use of RCA has no apparent direct influence on joint faulting (dowels, aggregate size, structural design parameters are more important)•Recycled ASR concrete used successfully in Wyoming with mitigation measures

•Isolated recurrent ASR•RCA performed better than control

•Recycled D-cracked concrete used successfully with mitigation measures

•Reduced aggregate size•Reduced moisture exposure?

Federal Highway Administration Minnesota Department of Transportation Jeff Sturtevant, Prof. David Gress and the

University of New Hampshire Recycled Materials Resource Center (RMRC)

Greg Cuttell, Julie Vandenbossche and many other former U-M Grad and Undergrad Research Assistants

Applied Research Associates, Inc. (formerly ERES Consultants)

Thank You!

Any Questions?