PCCP Preservation Steps to Take to Extend Pavement Life and Performance of Your Concrete Pavements Larry Scofield, P.E. International Grooving and Grinding Association 1
Big Preservation
Everybody Wins When it is Funded Roman Road Network Approximately Equal to the US Interstate System-- Cost $3.2 Million per Mile
Road Building/Preservation 1993 and 2014 1993 Lets Build 100 Miles of Road Funding 2014 Lets Build 67 Miles of Road Arizona Consumption Rate 1995 Lets Drive 39.7 Billion VMT 2014 Lets Drive 59.6 Billion VMT (50%)
Increase in Vehicle Miles Traveled and Miles of Roadway (1990-2012)
Standards in Vehicle Fuel Efficiency Gas Tax
It s a New Game In Town International Grooving & Grinding Association 7
FHWA Performance Measures Measure IRI (in/mi) Cracking Percent Surface All Pavement s Asphalt Jointed PCCP Population Consideration Population < 1 Million Population > 1 Million Good Fair Poor Good Fair Poor <95 95-170 >170 <95 95-220 >220 No Population Considerations Good Fair Poor <5 5-10 > 10 Assessment Rutting (in) Faulting (in) Cracking Percent Asphalt Jointed PCCP CRCP No Population Considerations Good Fair Poor < 0.2 0.2-0.4 > 0.4 No Population Considerations Good Fair Poor < 0.05 0.05-0.15 > 0.15 No Population Considerations Good Fair Poor < 5 5-10 > 10
Why Concrete Pavement Preservation Bellefontaine, Ohio 1925 2016= 125 th Anniversary
2016 = 123 rd Anniversary
Message Slide Funding and the Transportation System are Critical Components of the National Economy Preservation is Not Only Important it is Absolutely Necessary Times Have Changed International Grooving & Grinding Association 11
Concrete Pavement Preservation Guide
NHI Web Based Training Modules
Typical Concrete Preservation Activities Diamond Grinding or Diamond Grooving Partial Depth or Full Depth Repairs Dowel Bar Retrofit Joint Sealing or Resealing Slab Jacking Longitudinal Crack Stitching
Trigger Values for Preservation
Grinding Concrete
Diamond Grinding Equipment
IRI of Concrete Interstate Pavements Kentucky DOT PMS Results 120 110 112.1 100 IRI 90 80 74.5 70 60 2007 2008 2009 2010 2011 2012 Time
Full Depth Repair
Full-Depth Repairs Workhorse treatment Removal/replacement of concrete pavement at deteriorated joints/cracks Focus on workmanship Dowel bar installation Need for rapid opening times Accelerated materials Precast repairs
Full-Depth Repair May also need to: Stabilize Sub Base If distress greater than 1/3 ½ D
Full-Depth Repair
Dowel Bar Retrofit
Dowel-Bar Retrofit Also need to: Reseal Joints
Sealing and Resealing Sealant Nozzle Reservoir Backer Rod
Slab Stabilization/ Jacking
Cross Stitching
Cross Stitching Top View Transverse Joint See Note A 24 in. min. Cross-stitch Holes (Typ.) (Alternate sides of crack) Cross-sectional View 35-45 Slab Subbase See Note B 0.75-in. dia. Rebar Epoxy into Place T Note A: Distance between holes is 24 in. for heavy traffic; 36 in. for light traffic Note B: Determine distance from longitudinal crack to hole based on slab thickness T and drill angle. Slabs less than 12 inches thick require a 35 insertion angle.
Partial Depth Patching
Good Reference Material International Grooving & Grinding Association 31
Partial Depth Repairs (old) Repairs deterioration in the top 1/3 of the slab. Generally located at joints, but can be placed anywhere surface defects occur.......
Repair Layout (old) 2-6 in min. 2-6 in min. Spall Patch 2 in (min.) - t/3 (max.) t
Differences in New Manual T/2 CP Tech Center International Grooving & Grinding Association 34
Type 1 Repair Layout 2/23/2016 International Grooving & Grinding Association CP Tech Center35
Type 2 Repair Distress International Grooving & Grinding Association 36 CP Tech Center
Type 2- Repair Layout CP Tech Center International Grooving & Grinding Association 37
Type 3 -- Repair CP Tech Center International Grooving & Grinding Association 38
Size of Repairs (Old) Minimum length 12 in Minimum width 4 in Go beyond problem by 3-4 in Combine close patches (<2 ft) Repair entire joint if more than 2 patches
Repair Materials Concrete Mixes 3/8 Agg, w/c <.44, 1600-1800 psi, MnDOT Modified Hydraulic Cement Gypsum Based (1 hr opening, reinforcement) Calcium Aluminate (cold weather, conversion) Polymer Based Resinous Materials Agg added to resins, quick set, Magnesium Phosphate Sensitive to Water, limestone not acceptable
Bonding Agents Sand Cement Grouts (2c-1s-1w) Epoxy bonding agents 2/23/2016 International Grooving & Grinding Association 41
Construction of Partial- Depth Repairs
Finding Unsound Concrete Sounding the pavement: Hammer Steel rod Steel chain DULL SHARP Unsound-Delaminated Solid
Sounding the Pavement
Concrete Removal Sawing and chipping Carbide milling Transverse Longitudinal
Sawing Vertical cut at perimeters Diamond blade Depth to 2 in Overcut slightly
Chipping Break to minimum depth of 2 in (1/3 ½) slab thickness maximum) 30 lb maximum hammer 15 lb hammer preferable for control Spade bits preferable to gouge bits Do not expose dowels
Removal of Concrete with Jackhammer
Milling Machine Requirements: High horsepower rating 12-18 in milling head width Wheels preferable to tracks Transverse orientation Longitudinal orientation
Cold Milling Heads International Grooving & Grinding Association 50 Courtesy CP Tech Center
Transverse Orientation
Cleaning Sound to check for weak spots before cleaning Chip out with 15 lb hammer if necessary Sandblast bottom and sides Waterblast acceptable alternative: Waiting period to dry
Chipping out weak spots
Sandblasting
Blowing Compressed Air Remove Debris
Checking Patch For Cleanliness
Joint Insert Separates patch from adjacent concrete Reforms joint reservoir Provides uniform sealing reservoir MUST get below patch material Acceptable materials: Styrofoam Asphalt-impregnated fiberboard Fiberboard
Compressible Insert 3 in min. Spall Patch Compressible insert 1 in
If Insert Not Used... Point Bearing Popout & Breakage Joint Closure Debonding Expansion Expansion
Compressible Joint Insert
Cement Grout International Grooving & Grinding Association 61
Application of Grout Bonding Agent
Placing Patch Material Mix in small quantities Place from wheelbarrows or buggies soon after bonding grout Slightly overfill the patch area Use small spud vibrators (<1 in) Hold at 15-30 degrees Do not drag!!
Finishing & Texturing Match surrounding elevation (grinding) Work tool from center toward edges Texture similar to surrounding pavement Seal saw-cut runouts with grout or liquid epoxy
Patch Material Placement International Grooving & Grinding Association 65
Curing High Surface Area 1.5 to 2 Times Normal Application Rate
Joint Sealing Resealing joints will help prevent further damage Saw & air blast all joint faces before sealing Seal according to agency specifications (silicone, hot pour, etc.)
Opening to Traffic 3 methods: Specified minimum strength (1600-1800 psi) Specified minimum time after completing placement (5 or 10 hour patches) Maturity method (mix specific) Strength method preferred Variations in air temperature influence strength development
Summary Limit use to top 1/3 (1/2) of slab Avoid point bearing : Use a compressible insert in joints & cracks Cure properly Reseal Joints Quality is Job One
Questions