bridge deck cracking - cptechcenter.org nc2/01 darwin bridge deck cracki… · silica fume overlay...
TRANSCRIPT
![Page 1: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/1.jpg)
Bridge Deck Cracking
David DarwinUniversity of Kansas
National Concrete Consortium
Columbus, OHApril 27, 2016
![Page 2: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/2.jpg)
Research Sponsors
![Page 3: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/3.jpg)
OutlineScopeFindings SpecificationsField ExperienceTechnologies Under Active StudyConclusions
![Page 4: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/4.jpg)
Scope of WorkBeginning in 1991
Initiated bridge deck crack surveys using standardized methods (150+ decks)
Established principal factors controlling cracking
![Page 5: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/5.jpg)
Scope of WorkBeginning in 2005
Constructed 25 bridge decks under Low Cracking High-Performance Concrete (LC-HPC) specifications (17 in Kansas)
Most bridges in study have steel girders
![Page 6: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/6.jpg)
Findings
![Page 7: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/7.jpg)
What’s not a major concernMoment region and load-induced stresses in the deck
![Page 8: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/8.jpg)
8
Moment region
7% Silica Fume Overlay
![Page 9: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/9.jpg)
9
Moment region
Conventional Overlay
![Page 10: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/10.jpg)
10
Moment region
Monolithic
![Page 11: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/11.jpg)
11
Moment region
Monolithic
![Page 12: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/12.jpg)
Factors
Age Bridge Deck Type Material Effects Site Conditions – Temperature Curing Date of Construction
![Page 13: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/13.jpg)
Monolithic
Age
0.00
0.20
0.40
0.60
0.80
1.00
1.20
0 25 50 75 100 125 150 175 200 225 250 275
Cra
ck D
ensi
ty, m
/m2
Bridge Age, months
![Page 14: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/14.jpg)
14
Bridge Deck Type
MonolithicConventional OverlaySilica Fume Overlay
![Page 15: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/15.jpg)
Bridge Deck Type
0.51 0.490.44
0.33
0.000.100.200.300.400.500.600.700.800.90
7% SFO 5% SFO CO MONO
Bridge Deck Type
Cra
ck D
ensi
ty, m
/m2
Age
Cor
rect
ed
Number of Bridges
(9) (18) (30) (16)
Number of Surveys
(9) (36) (52) (32)
![Page 16: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/16.jpg)
Material EffectsConcrete Mixture Proportions
Water contentCement contentVolume of cement paste
SlumpCompressive strengthAir content
![Page 17: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/17.jpg)
Paste Content
0.19 0.16
0.680.73
0.000.100.200.300.400.500.600.700.800.90
26 27 28 29
Percent Volume of Water and Cement, %
Cra
ck D
ensi
ty, m
/m2
Age
Corre
cted
Number of Placements
Number of Surveys
(8) (16) (4) (5)
(16) (31) (8) (11)
Monolithic
![Page 18: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/18.jpg)
0.18
0.31
0.51
0.87
0.11 0.15 0.19 0.22
0.000.100.200.300.400.500.600.700.800.90
38 (1.5) 51 (2.0) 64 (2.5) 76 (3.0)
Slump, mm (in.)
Cra
ck D
ensi
ty, m
/m2
Age
Cor
rect
edUncorrectedAdjusted for Water Content
Number of Placements
Number of Surveys
(5) (20) (5) (1)
(10) (40) (11) (3)
Slump
Monolithic
![Page 19: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/19.jpg)
Settlement Cracking
![Page 20: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/20.jpg)
Compressive Strength
0.160.26
0.49
0.000.100.200.300.400.500.600.700.800.90
31 (4500) 38 (5500) 45 (6500)
Compressive Strength, MPa (psi)
Cra
ck D
ensi
ty, m
/m2
Age
Corre
cted
Number of Placements
Number of Surveys
(7) (12) (10)
(13) (24) (23)
Monolithic
![Page 21: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/21.jpg)
0.37 0.38
0.13
0.000.100.200.300.400.500.600.700.800.90
4.5 5.5 6.5
Air Content, %
Cra
ck D
ensi
ty, m
/m2
Age
Cor
rect
ed
Number of Placements
Number of Surveys
(7) (19) (5)
(14) (40) (10)
Air Content
Monolithic
![Page 22: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/22.jpg)
0.19
0.330.37
0.44
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
5 (41) 15 (59) 25 (77) 35 (95)
High Air Temperature, C (F)
Crac
k Den
sity,
m/m
2
Age C
orre
cted
Number of Placements
Number of Surveys
(4) (15) (9) (4)
(8) (31) (17) (9)
High Air Temperature
Monolithic
![Page 23: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/23.jpg)
5/3/2016 23
Date of Construction
![Page 24: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/24.jpg)
0.16
0.50
0.000.100.200.300.400.500.600.700.800.90
1984-1987 1990-1993
Date of Construction
Crac
k Den
sity,
m/m
2
Age-
Corre
cted
Number of Bridges
(6) (7)
Number of Surveys
(12) (16)
Date of Construction - Monolithic
![Page 25: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/25.jpg)
0.24
0.53
0.81
0.000.100.200.300.400.500.600.700.800.90
1985-1987 1990-1992 1993-1995
Date of Construction
Crac
k Den
sity,
m/m
2
Age C
orre
cted
(6) (36) (6)
(6) (17) (3)Number of BridgesNumber of Surveys
Date of Construction - Conventional Overlays
![Page 26: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/26.jpg)
0.87
0.55
0.420.48
0.000.100.200.300.400.500.600.700.800.90
1990-1991 1995-1996 1997-1998 2000-2002
Date of Construction
Crac
k Den
sity,
m/m2
Age C
orre
cted
(6) (20) (16) (10)
(2) (10) (8) (10)Number of BridgesNumber of Surveys
Date of Construction - Silica Fume Overlays
![Page 27: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/27.jpg)
Control of early evaporation and improved curing
![Page 28: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/28.jpg)
0.87
0.58 0.61
0.390.48
0.000.100.200.300.400.500.600.700.800.90
NONE R1, R2 R3 R4, R5, R6 R8, R9
Special Provision, (R#)
Crac
k Den
sity,
m/m2
Age C
orrec
ted
(6) (8) (10) (18) (10)
(2) (4) (5) (9) (10)Number of BridgesNumber of Surveys
Control of early evaporation and improved curing -Silica Fume Overlays
![Page 29: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/29.jpg)
Why increased cracking?
Cement finenessConcrete slumpPlacing equipmentFinishing equipment
![Page 30: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/30.jpg)
1
2
3
4
5
6
7
8
9
10
1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Slum
p, in
.
Placement Date
MONO
CO Subdecks
5% SFO Subdecks
7% SFO Subdecks
![Page 31: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/31.jpg)
Overall ApproachWork to reduce plastic, settlement, thermal
and drying shrinkage cracking
Low cement & water contentsLow slumpModerate, not high, strengthControl concrete temperatureMinimum finishingEarly start and extended curing
![Page 32: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/32.jpg)
LC-HPC Specifications Optimized Aggregate Gradation Low-absorption Aggregate 1 inch Max Size Aggregate Cement Content ≤ 540 lb/yd3
w/c ratio = 0.43 – 0.45 Air Content of 8 ± 1½% Designated slump 1½ – 3 in. (3½ in. max) Controlled temperature (55 – 70°F) Improved curing
![Page 33: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/33.jpg)
Thermal Cracking
Rule of Thumb: Cracking will result when temperature of plastic concrete in deck exceeds temperature of girders by more than 36° F (20° C).
![Page 34: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/34.jpg)
Concrete temperature control
55 – 70°F50 – 75°F if approved by Engineer
![Page 35: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/35.jpg)
Cold-weather concreting
Maintain temperature of both girders and deck
![Page 36: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/36.jpg)
Alternatives to Pumping
Concrete Buckets Conveyor Belts
![Page 37: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/37.jpg)
![Page 38: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/38.jpg)
![Page 39: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/39.jpg)
PlacingAir cuff/bladder valve on pump or limit drop with conveyorFilling end walls and diaphragms ahead of slab
![Page 40: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/40.jpg)
Consolidation RequirementsVertically mounted internal gang vibrators
![Page 41: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/41.jpg)
Concrete Finishing
General Rule:Less is More
Pan or burlap dragBullfloatingNo finishing aids!
![Page 42: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/42.jpg)
Curing
Presoaked burlapTimely placementConstantly wet Spray hoses Soaker hoses 14 days
![Page 43: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/43.jpg)
![Page 44: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/44.jpg)
Curing
14 days wet cure with burlap, soaker hoses, and plastic
Followed by curing compound to slow the rate of evaporation
![Page 45: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/45.jpg)
Field Experience
![Page 46: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/46.jpg)
0
0.2
0.4
0.6
0.8
1
1.2
0 12 24 36 48 60 72 84 96 108 120
Cra
ck D
ensi
ty (m
/m2 )
Bridge Age (Months)
Control
LC-HPC
![Page 47: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/47.jpg)
Bridges 1 and 2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 12 24 36 48 60 72 84 96 108 120 132
Cra
ck D
ensi
ty (m
/m2 )
ControlLC-HPC
Bridge Age (Months)
Control-1/2 - P2Control-1/2 - P1
LC-HPC-1 - P2LC-HPC-1 - P1
LC-HPC-2
![Page 48: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/48.jpg)
Bridges 11 and 13
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 12 24 36 48 60 72 84 96 108
Cra
ck D
ensi
ty (m
/m2 )
Bridge Age (Months)
Control-11
LC-HPC-13
Control-13
LC-HPC-11
![Page 49: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/49.jpg)
Bridge 4
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 12 24 36 48 60 72 84 96 108
Cra
ck D
ensi
ty (m
/m2 )
Bridge Age (Months)
Control-4
LC-HPC-4 - P1
LC-HPC-4 - P2
![Page 50: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/50.jpg)
High Air Temperature
KU11
KU 5 KU3
KU6
KU7
KU9
KU4-p2
KU13
KU2 KU 1-p1KU1-p2
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
56 60 65 69 71 78 78 79 84 87 88
Cra
ck D
ensi
ty, m
/m2
at 3
6 m
onth
s
Daily High, °F
![Page 51: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/51.jpg)
Technologies Under Active Study
Internal curing with pre-wetted lightweight aggregate combined with slag cement and silica fumeShrinkage reducing admixturesShrinkage compensating admixturesRheology modifying admixturesSynthetic fibers
![Page 52: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/52.jpg)
Reducing shrinkage cracking using:
Internal curing with pre-wetted lightweight aggregate combined with slag cement and silica fume
![Page 53: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/53.jpg)
Internal Curing Shrinkage
-100
0
100
200
300
400
500
600
700
0 50 100 150 200 250 300 350
Aver
age
Free
Shr
inka
ge (m
icro
stra
in)
Drying Time (days)
Control
10% LWA
10% LWA,30% Slag
10% LWA,30% Slag, 3%SF
![Page 54: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/54.jpg)
Reducing settlement cracking using:
Rheology modifying admixtures
Synthetic fibers
![Page 55: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/55.jpg)
![Page 56: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/56.jpg)
Control mixture
![Page 57: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/57.jpg)
Synthetic fibers
![Page 58: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/58.jpg)
Rheology modifying admixture
![Page 59: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/59.jpg)
Conclusions
Material properties and construction procedures are the principal factors controlling cracking in bridge decks
![Page 60: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/60.jpg)
ConclusionsLow-slump, moderate-strength concrete results in less cracking than high-slump, high-strength concrete
![Page 61: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/61.jpg)
Conclusions
Best performance requires adherence to all aspects of the specifications
![Page 62: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/62.jpg)
![Page 63: Bridge Deck Cracking - cptechcenter.org NC2/01 Darwin Bridge Deck Cracki… · Silica fume overlay bridge decks improved greatly ... 1 inch Max Size Aggregate Cement Content ≤540](https://reader038.vdocument.in/reader038/viewer/2022110110/5a7762fa7f8b9ad22a8e2554/html5/thumbnails/63.jpg)
The University of Kansas
David Darwin, Ph.D., P.E.
Deane E. Ackers Distinguished Professor and ChairDept. of Civil, Environmental & Architectural Engineering2150 Learned HallLawrence, Kansas, 66045-7609785 864-3827 Fax: 785 864-5631