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Pervious Concrete Pavement 4825 Butler Road, Glyndon Maryland. Demonstration Panel October 12, 2007. Pervious Concrete Pavement 4825 Butler Road, Glyndon Maryland. Pervious Concrete Pavement 4825 Butler Road, Glyndon Maryland. Pervious Pavement Section. Underdrains. Inlet Detail.
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Pervious Concrete Pavement4825 Butler Road, Glyndon Maryland Work In Progress
Specifications and Testing forPervious Concrete • Rod Meyers, P.E., CDT, BASF • Matt Cockerham, North Star
Specifications and Testing forPervious Concrete • Desired Plastic Properties • Desired In Place Properties • Common Specification Provisions
Desired Plastic PropertiesBatching Consistency ASTM C 143, Slump Test, does not apply
Desired Plastic PropertiesStable Paste • Improves permeability • Improves abrasion resistance • Improves cold weather durability
Desired Plastic PropertiesWorkability • Maintains w/cm • Permits timely unloading, placement, finishing, and curing
Desired In Place PropertiesPercolation 3 to 5 gal/ft2/min = 288 in./hr to 480 in./hr = 4.8 in./min to 3.2 in/min
Desired In Place PropertiesPercolation • ASTM developing test method to measure percolation • Constant head method
Measuring VoidsTesting Fresh Density • Sample in accordance with ASTM C 172 • Sample every 100 cubic yards • Within +/- 5 lb/ft3 of specified density
Testing Fresh DensityASTM C1688 Density and Void Content of Freshly Mixed Pervious Concrete • 0.25 ft3 measure (standard air pot) • Standard Proctor Hammer • Fill in two lifts • Drop hammer 20 times/lift
Testing Fresh DensityAlternate Methods • ASTM C29 Jigging Procedure • ASTM C138 Rodding Procedure • Filling an empty unit weight bucket
Usable Voids vrs. Gravimetric VoidsEffective Porosity vrs. Total Voids Usable Voids, % = 0.898 * (Gravimetric Voids, %) – 3.1
Usable Voids vrs. Gravimetric Voids A 4 inch thick pervious pavement with 15% usable (effective) voids will store 0.60 inches of rainwater (4” * 0.15 = 0.60”)
Desired In Place PropertiesMechanical Strength • Rigid Pavement • Flexural Strength
Flexural Strength vrs. Void Content Flexural Strength, Fmr = 832.8 – 20.3 * (void content, %), psi
Pavement Serviceability • AASHTO Road Test • Relationship between serviceability and load repetitions
Estimating Flexural Stress ACI 330 Guide for The Design and Construction of Concrete Parking Lots
Desired In Place PropertiesAbrasion Resistance • Strong, dense surface • Good curing
Desired In Place PropertiesCold Weather Durability • Freeze-thaw Durability • Frost Heave
Frost Heave • Frost Penetration Depth in MD = 30” • FAA recommends 65% of the frost depth contain non-frost-susceptible material • For 30” FPD, depth of pervious material (concrete plus base) shall be 20 inches
Cold Weather Durability • ASTM C 666 testing has indicated low durability • Field service says otherwise
Mix Design Development for Pervious Concrete in Cold WeatherSponsored by:Iowa Department of Transportation National Concrete Technology Pavement Technology CenterIowa Concrete Paving Association
Conclusions • Failure due to freeze-thaw cycles are the result of aggregate deterioration or cement paste matrix failure • Sand, latex and air entrainment admixture improved freeze-thaw durability
The Effect of Coarse Aggregate on the Freeze-Thaw Durability of Pervious ConcreteJohn T Kevern, University of Missouri-Kansas CityKejin Wang, Iowa State UniversityVernon R Schaefer, Iowa State University
Conclusion and Recommendations Aggregate absorption has the greatest effect on freeze-thaw durability
Suggested Methods to Improve Cold Weather Durability • Use 8” to 24” of Open Graded Base • Use Sound Aggregates • Use Air Entraining Admixture • Use 5 to 10% Fine Aggregate • Place perforated PVC pipe in base to capture and remove water
Contractor QualificationsOptions – On Site • 1 NRMCA Certified Pervious Concrete Craftsman • 3 NRMCA Certified Pervious Concrete Installers • 5 NRMCA Certified Pervious Concrete Technicians
Pre-paving Conference • Within two weeks of first placement • In attendance: Owner’s Representative Contractor Concrete Supplier Concrete Foreman Testing Agency
Test Panel • Minimum 225 ft2 • Use proposed mix design and materials • Use proposed placement equipment • Include at least one typical joint
Test Panel • Fresh density: with +/- 5.0 lb/ft3 • Three cores: average thickness not more than ¼” less or 1.5” more than specified thickness • Single core: not more than ½” less than specified thickness
Testing Thickness • Average of three cores more than 1-1/2” greater than specified thickness • No single core more than ½” less than specified thickness
Testing Thickness • Three cores per 5,000 ft2 • Average of three cores not more than ¼” less than specified thickness
Testing In Place Density • Three cores per 5,000 ft2 • Minimum nominal diameter of 4 inches • Measure density in accordance with ASTM C140 • Hardened density shall be within +/- 5% of approved hardened density from test panels
Subgrade Preparation • Maintain final subgrade elevation • Permeability testing: Portland Cement Association recommends: Soils with a percolation rates of ½ in/hr. ASTM D 3385, Double-ring Infiltrometer testing • Subgrade support: minimum density of 92% maximum dry density • Subgrade in moist condition within 3% of optimum moisture content
Base Materials • Open graded aggregate • 30% to 40% void content • Elevation of base shall be maintained during placement of concrete.
Concrete Materials • Comply with ASTM C 94 • Aggregates – Max. size 1/3” thickness • Aggregates – Use 3/8” maximum size • Admixtures for controlling hydration may be used and facilitate handling of plastic concrete