Delft University of Technology
Active Crack Control of Continuously Reinforced Concrete Pavements Through Partial Surface Notches-Field Investigation
Dongya REN, PhD Students
Promotor: Prof.dr.ir. S.M.J.G. Erkens
Copromotor: Ir. L.J.M. Houben
Road Engineering, CEG, TU Delft
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Why is CRCP used?
Antwerp Ring 1,CRCP, rebuilt in 2004
200,000 vehicles per day
• Low maintenance
• Heavy Traffic
• Smoothness
• Longer lasting (Design life 40 years)
• Less costly (Life cycle cost analysis)
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• Motorway E40 Brussels- Liege
• Built in 1971
• Excellent performance!
• E313, Herentals-Antwerp • Rebuilt in 2012
• Active crack control
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Concept 1
1970-1981
• 0.75%(φ18mm@150mm), H=200mm, Asphalt interlayer
• Unfavorable crack pattern ( L= 0.4~0.6 m about 18 years, cluster of closely spaced cracks)
• Some sections still behave quite well after 40 years of services
Concept 2
1981-1995
• 0.67%(φ16mm@150mm), H=200mm, No Asphalt interlayer
• Ideal crack pattern ( L= 1.4~2.4m, 70% within 0.8-0.3m)
• Punchout problems due to the erosion of the base layer
Concept 3
1995-Now
• 0.75%(φ16mm@150mm), H=230-250mm, Asphalt interlayer
• L is about 1.0m about 2 years with clusters of closely spaced crack(few data available)
• Behave perfectly
CRCP Design Concept Change in Belgium
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Characteristics of crack spacing of concept 3 in Belgium
S. Holler (2009) E40(Walshoutem), E34(Antwepen) F. Feys (2010) E40(Affigem), N255 J. Van. Avermaet (2010) E17(Kruishouterm) D. Ren (2011,2012) E17(De Pinte), E313(Active crack control)
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Problem
• Non-uniform crack patterns are detrimental and common
• They can lead to spalling and punchout
Punchouts
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A12 Design features of A12 • Reconstructed in 1998
• Porous Asphalt + CRCP
• 40 Years Design Life
• 100,000 ADT
• 5 cm Porous Asphalt • 25 cm CRCP, 0.7% steel • 6 cm dense Asphalt base • 25 cm cement bound
recycled asphalt sub-base
A5, A12, A50, A59, A73/74
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CRCP in Netherlands
Schematic view of crack map in CRCP on November 9, 2013, on A50. The red line represents a crack with reflective crack, the blue line represents a crack without reflective crack.
0 5 10 15 20 25 30 35 40 45 50
50 55 60 65 70 75 80 85 90 95 100
R R R R R R R R
R R R R RRR
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Active Crack Control
Tape Insertion
Partial surface notches
Transverse surface notches
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Active Crack Control
0.4 m
1.2 m
• saw cut length : 400 mm • saw cut interval: 1200mm • saw cut depth: 30 mm &60 mm • Saw cut time: Immediately after the surface treatment but for sure within 24 hours after placement
6 cm
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Monitoring Program
• Concrete temperature
• Concrete properties • Crack width
• Crack movement
• Crack spacing
Passive Crack Control Test section E17 2.0 km long test section 6 surveys Active Crack Control Test section E313 1.6 km long test section 5 surveys
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Effectiveness of crack inducer
Percentage of Cracks Initiated at the Notches
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Crack spacing
Comparison of Cumulative crack spacing distribution between E17 and E313
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0.0 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.4 6.0
Cu
mu
lati
ve
per
cen
tag
e
Crack spacing (m)
E313- 60 mm-12 months
E313-30 mm- 14 months
E17- 0.75%- 12 months
27.6%
66.0%
74.3%
Desirable Crack Spacing range: 0.6 m~2.4 m
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Crack spacing
Average crack spacing for five consecutive cracks
Uniformer Better Crack Spacing Distribution
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Cluster cracks
Cluster cracking probability
A typical section with clusters of closely spaced cracks in E17
(Conventional CRCP section)
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Crack Pattern
Straighter
E17
E313
E313
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Crack width measurement
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Crack Width
60 mm depth saw cut section
10 months (03-04-2013)
4.2 ℃
Crack width measured on the surface in
E313
60 mm depth saw cut section
2 days (13-09-2012)
25.0 ℃
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Crack Width
Crack Width on the Pavement Surface Measured by Microscope
Crack Width Limitation of CRCP in the Netherlands: 0.4 mm
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Summary of findings and Conclusions
• A CRCP with an active crack control system outperform CRCP with passive
crack control because of crack pattern are more uniform, straighter.
• CRCP with 6 cm depth saw cut perform much better than the one with 3 cm
depth saw cut.
• All test sections meet the crack width requirement.