Arya Institute Of Engineering Technology & Management

Submitted to:- Submitted By:-Mr. Gori Shankar Soni Chandra Mohan LodhaHead Of Department Rollno:13EAOCE016

Seminar Co-ordinator 4th Year (CE) Ms. Geetanjali Ganguly

CONTINUOUSLY REINFORCED CONCRETE PAVEMENT

ContentsIntroductionCRCP CharacteristicsWhy Continuously Reinforced Concrete PavementsCRCP Cross-Section Typical CRCP Design Features CRCP FailurePerformance FactorsConstruction Issues FAA Design Method Of CRCPCRCP SummaryConclusion

IntroductionContinuously reinforced concrete pavements (CRCP) is a type

of concrete pavement that does not require any transverse contraction joints.

Transverse cracks are expected in the slab, usually at intervals of 1.5 - 6 ft (0.5 - 1.8 m).

CRCP designs generally cost more than JPCP or JRCP designs initially due to increased quantities of steel.

CRCP utilizes reinforcing steel to effectively eliminate transverse joints in favor of very tightly maintained cracks.

Once CRCP roads are constructed they need not to be taken care of for the next 50-60 years.

The performance of continuously reinforced concrete pavement (CRCP) constructed in 1995 that utilized recycled concrete aggregate (RCA) as both coarse and fine aggregates.

CRCP Characteristics

• No joints• Steel reinforcement bars• Numerous transverse cracks

History• First used in 1921• Experimental sections in the

1940’s• More than 28,000 miles in

the USA

Why Continuously Reinforced Concrete Pavements?• Smoothness

• Low maintenance costs– No transverse joints

• Thinner slab thickness relative to jointed concrete pavement

• Long Life

CRCP Cross-Section

Typical CRCP Design Features• Concrete thickness (8 to 17 in.)• Depth to steel (3.5in to h/2)• Crack spacing

– natural vs. induced• Steel Bar Size (#5, #6, #7, 25-30D)• Steel Fe-415• 2-layer vs. 1-layer Steel

Aggregate Subbase

Asphalt Concrete Base

Single Layer Steel

Two-Layer Chairs

Two-Layer Steel

Longitudinal Steel Placement

Concrete Placement

Soff-Cut “Joints”

CRCP Failure• Deterioration of transverse cracks (Spalling)• Punchouts

x

y

CRCP Distress Development PunchoutIn continuously reinforced concrete pavement, the area enclosed by two closely spaced (less than 3 ft or 1m) transverse cracks, a short longitudinal crack, and the edge of the pavement or longitudinal joint, when exhibiting spalling, shattering, or faulting. Also, area between Y cracks exhibiting this same deterioration.

Performance Factors• Crack spacing• Crack width• Construction Time

– Temperature / humidity / curing– Thermal contraction

• Concrete materials– Cement content, aggregates, proportions– Drying shrinkage

Construction Issues• Concrete mix design

– Concrete shrinkage– Lower zero stress temperature!

• Mix temperature (water,aggregates)• Mix proportions (max. size aggregate)

• Curing– Minimize climatic effects– Solar radiation, wind, evaporation

• Base temperature (asphalt concrete)

FAA Design Method for CRCP• Use same thickness as JPCP• Crack Spacing = 2 to 10 ft.• Steel content = 0.5 to 1.0%

Steel content must satisfy all three criteria:1) Subgrade restraint2) Temperature Effects3) Concrete to Steel Ratio

CRCP Summary• Crack spacing• Crack width• Construction• Materials• Load capacity

Conclusion Compared to flexible pavement, CRCP gives additional design life of at least 10 years.

The demerit of CRCP is its high initial cost & difficulty in repair works required to be done if not constructed properly.

Joint less concrete pavement, CRCP offers excellent smooth Riding surface for the vehicles that maximizes the comfort for the passengers.

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