Concrete Pavement Preservation and Optimization State of the Art Treatments to Increase Pavement Longevity and Performance International Grooving and Grinding Association
Priorities Have Shifted Minimal system expansion Maintain the present system Minimize traffic disruptions Increase safety Address operator comfort Reduce Roughness Reduce Noise Save money Protect the Environment
Tomorrow s Technologies Here Today Transportation agencies already have access to a variety of sustainable, concrete-based pavement maintenance and repair solutions. What is needed is not necessarily new technologies or solutions, but a new, proactive mindset toward using them.
Concrete Pavement Preservation
Rehabilitation Timing Structural / Functional Condition Preservation Restoration Min. Acceptable Rating Resurfacing Reconstruction Age or Traffic
Concrete Preservation with Diamond Grinding Was First Used in California Diamond grinding was first used in California in 1965 on a 19-year old section of I-10 to eliminate significant faulting (Neal and Woodstrom 1976). In 1983, CPR was conducted on this same pavement section, including the use of additional grinding to restore the rideability and skid resistance of the surface. In 1997, the process was repeated. Since its first use in 1965, the use of diamond grinding has grown to become a major element of PCC pavement preservation.
California I-10
Effectiveness of Diamond Grinding - CALTRANS CALTRANS has determined that the average life of a diamond ground pavement surface is 17 years and that a pavement can be ground at least three times without affecting pavement structurally. See IGGA.net for full report
PCCP Preservation Techniques Structural vs Functional? What is the difference?
PCCP Preservation Techniques Slab stabilization/jacking Partial-depth repair Cross-stitching longitudinal cracks/joints Retrofitting dowels Full-depth repair Diamond grinding Diamond grooving Joint & crack resealing
Undersealing Pressure insertion of flowable material beneath the PCC slab Insertion point
URETEK METHOD
Performance Short- and long-term reductions in pavement deflections Most effective on pavements with little structural damage Cost effective alternative to remove and replace when slabs are in good condition
Partial-Depth Patching
Partial Depth Repairs Repairs deterioration in the top 1/3 of the slab. Generally located at joints, but can be placed anywhere surface defects occur.......
Trunk Highway 53 Ramp Duluth, MN - 1994
Load Transfer Restoration Dowel Bar Retrofit
Purpose of Load Transfer Restoration Reestablish loadtransfer across joints or cracks Load-transfer is a slab s ability to transfer part of its load to its neighboring slab Used in JRC and JPC pavements to limit future faulting L= x U= 0 Load Transfer = 0% (Poor) L= x U= x Load Transfer = 100% (Good)
Load Transfer Restoration Placement of load transfer devices across joints or cracks of existing pavements Candidate projects Poor load transfer (< 70 %) Pumping Faulting Corner breaks
Slot Locations in a Lane Centerline 3 slots per wheelpath Spaced 12 inches apart Outside dowels should be 12 to 18 inches from edge Inside dowels should be 24 inches centerline Must not come into contact with adjacent tiebars 12-18 inches 24 inches 2 groups of 3 bars 12 inches on center
Dowel Slot Alignment Must always be parallel to centerline Must be cut so at least one-half of dowel can be on each side of the joint or crack Correctly Aligned Dowel Slots Centerline Incorrectly Aligned Dowel Slots
Slot Creation Close-Up of Sawblades
Washington State DBR Experience DBR test section conducted in 1992 Full-scale use of DBR began in 1993 Heavily faulted interstate pavements 280 Ln-mi (450 Ln-km) or 600,000 bars IGGA/ACPA CPR Division 38
Full-Depth Patching Operations
Full-Depth Repair Purpose Restore structure Restore ride Used for: Joint deterioration Transverse cracking Longitudinal cracking Broken slabs & corner breaks
Pre-cast Pavement Panels
In Situ Full Depth Repair
Performance of Full-Depth Repairs Can provide 20 or more years of service when properly designed and constructed High-early strength materials allow early opening to traffic and limited lane closures
Diamond Grinding Grinding
What is Diamond Grinding? Removal of thin surface layer of hardened PCC using closely spaced diamond saw blades; Results in smooth, level pavement surface; Longitudinal texture with desirable friction and low noise characteristics; Frequently performed in conjunction with other CPR techniques, such as full-depth repair, dowel bar retrofit, and joint resealing. Comprehensive part of any PCC Pavement Preservation program;
Diamond Grinding
Diamond Grinding Grinding Process
Diamond Grinding
Advantages of Diamond Grinding Cost competitive; Enhances surface friction and safety; Can be accomplished during off-peak hours with short lane closures and without encroaching into adjacent lanes; Grinding of one lane does not require grinding of the adjacent lane; Does not affect overhead clearances underneath bridges; Blends patching and other surface irregularities into a consistent, identical surface; Provides a low noise surface texture!
Pavement Problems Addressed Faulting at joints and cracks Built-in or construction roughness Polished concrete surface Wheelpath rutting Permanent upward slab warping Inadequate transverse slope Unacceptable noise level
Faulted Joints
Diamond grinding can provide a 60% to 70% improvement over the pre-grind profile on average!
I - 635 WB Lanes K1, K2 K3 & K4 250 Before Average After Average Average Average 200 Before Grinding 698 Bumps 150 152 Average IRI 100 61 50 After Grinding 29 Bumps 0
Safety, Surface Texture and Friction Increased macrotexture of diamond ground pavement surface provides for improved drainage of water at tire-pavement interface Longitudinal texture provides directional stability and reduces hydroplaning (side-force friction) Grooves provide escape route for water trapped between tire and pavement surface In Wisconsin, overall accident rates for ground surfaces were 40% less than for unground surfaces over a 6-year period, 57% in wet weather conditions(drakopoulos et al. 1998)
Safety Increased macrotexture of diamond ground pavement surface provides for improved drainage of water at tire-pavement interface Grooves provide escape route for water trapped between tire and pavement surface Reduces the potential for hydroplaning
Wheel Path Rutting
Curling
Unacceptable Noise Level
California and Arizona PCCP SI Test Results
Traffic Management Minimal traffic control required Perform off-peak hours Short closures - re-open lanes as needed No equipment encroachment into other lanes Can do just one lane Does not affect overhead clearances
Pilot Cars
Why Diamond Grinding for City Streets? Diamond Grinding does not reduce the reservoir capacity of the gutter Curb reveal is not reduced Man-hole covers and drainage inlets do not require adjustment Guide-rails and overhead fixtures do not require adjustment Residential driveways do not require expensive tie-in operations
Gutter Capacity Unaffected
Maintain Curb Reveal
Manholes Do Not Require Adjustment
No Additional Work at Driveway Entrances
Lower Ambient Temperatures and Energy Costs
Costs Depends on Aggregate and PCC mix properties; Average depth of removal; Smoothness specifications; Size of the project; Work schedule; Cost effective whether used alone or as part of a comprehensive CPR program. In most cases, the cost of diamond grinding is only about half the cost of bituminous overlay.
Costs Soft limestone as low as $1.50 per sq. yd. Hard river gravel as high as $10.00 per sq. yd. Typical price $2.00 to $4.00 per sq. yd. *for a job with min. 20,000 sq. yds. and reasonable traffic control requirements
Next Generation Concrete Surface (NGCS)
Next Generation Concrete Surface CDG Texture NGCS Texture
Diamond Grinding Width of diamond blades (.10 to.125 inches) Saw blade thickness (.125 in) Land area -.080 inches for hard aggregate -.110 inches for soft aggregate Diamond Grooving (.75 in).125 to.25 inches
Diamond Grooving Grooving
Diamond Grooving Cutting parallel grooves into the pavement using diamond saw blades Longitudinal vs. transverse Benefits Improved wet weather friction Reduction in splash and spray Grooving
Why Longitudinal? Better Vehicular Guiding Effect particularly on curves Added Resistance to lateral skidding Anticipated Better Performance would wear longer Expected Less Noise interior vehicle & exterior tire Less Wet Weather Accidents Earlier grooving studies showed decrease
Reduction of Wet Pavement Accidents on Los Angeles Metropolitan Freeways Before After
Reduction of Wet Pavement Accidents on Los Angeles Metropolitan Freeways Before After
Reduction of Wet Pavement Accidents on Los Angeles Metropolitan Freeways Before After
Reduction of Wet Pavement Accidents on Los Angeles Metropolitan Freeways Before After
Transverse Diamond Grooving Grooving
Diamond Grooving Transverse Grooving Advantages Most direct channel for water drainage Introduces a surface that provides significant braking traction Disadvantages Maintaining adjacent traffic Excessive noise Productivity
Grooved section When Wet
Joint/Crack Resealing Application of a sealant material in concrete pavement joints and cracks Purpose Minimize moisture infiltration Prevent intrusion of incompressibles Sealant Materials Rubberized asphalt Silicone
PCC Joint Sealing Current Practice Debate: to seal or not to seal Some believe the benefits do not offset the costs Most agencies seal and reseal transverse joints Recommendation: continue to reseal joints if they were originally sealed!
Performance of Joint Resealing Original sealant typically requires resealing after 5 to 12 years Resealing required every 5 to 8 years thereafter Regular resealing may extend pavement life Most beneficial on pavements that are not badly deteriorated
Sealant Material Desirable Sealant Properties Durability Extensibility Resilience Adhesiveness Cohesiveness Resistance to traffic, moisture, sunshine, and climatic variation Deformation without rupturing Recovery from deformation and resist stone intrusion Adherence to joint/crack walls Resistance to internal stresses (rupturing from elongation)
Summary Many available rehabilitation treatments for PCC pavements Each has advantages and limitations Performance and cost vary with given conditions Applying the right treatment to the right pavement at the right time No universal method available Take advantage of local contractor experience IGGA & ACPA are ready to assist
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