Weiss, W. Jason

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Recent Developments in Porous Concrete Paving MaterialsNarayanan Neithalath, Rolando Garcia, Will ThorntonJason Weiss, Jan Olek, Bob Bernhard765-494-2215 or wjweiss@ecn.purdue.eduPurdue Road School - March 25, 2003School of Civil EngineeringPurdue University, West Lafayette, IndianaThe Need for PavementsThe Time When Cursing Was Louder thanPavement-Tire InteractionReducing Noise Through Enhanced Porosity Concrete• Increasing the porosity of the non-aggregate component of the material• Why do we think that this will work 1. Dissipate Energy Through Friction2. Reduces Surface Area and Resulting “Slapping Sound”3. Reduces “Horn Effect”Blocks ‘Snap-Out’Driving DirectionPavementBlock ImpactAir PumpingHighest Slip VelocitiesContact LengthTread Block SlipOther Benefits of Enhanced Porosity Concrete• Work for tire and drive train noise as well• Rapid drainage of water through interconnected voids– Minimizes spray– Minimizes glare• In the south this is being used for “permeable” parking lotsInfluence of Porous PavementsCaestecker 199740 60 80 100 120 140Test Speed (km/hr)84889296100104RollingNoiseMeasuredUsingTrailer-Method(dB)Dense AsphaltFine Agg. ConcretePorous AsphaltPorous ConcreteRollingNoiseMeasuredUsingTrailer-Method(dB)Hans Arrino (mid 19th Century)SafetyCostResearch Objective • Determine whether porous pavements can reduce the total noise level while avoiding potential problem associated with high-porosity pavements such as reduced durability• Balance Safety, Mechanical, Durability, and Sound Performance– Determine Optimal Porosity– Determine Proportioning ProceduresSoundMechanicalDurabilityPorositySpecimen Geometries and Test ProceduresFlexural Strength #1SpanLoad Casting DirectionFlexural Strength #2SpanCasting DirectionFor Each Mixture – Cast 6 in x 6 in x 28 in BeamCasting DirectionSound MeasurementSectioning For Sound and Porosity MeasurementPorosityMeasurementMixtures Investigated• Influence of Gap Grading and Aggregate Size (#8, #4, 3/8”)• Influence of Blending Aggregates (#8/#4, #8/3/8”, #4/3/8”)• Influence of Silica Fume• Influence of Sand Content• Influence of W/C (To Come)• Influence of Fibers (To Come)• Micro-particulate (To Come)Mixture I.D.3/8" Aggregate#4 Aggregate#8 AggregateFine Aggregate (Sand)Water-to-Cement RatioSilica Fume Addition by Cement Weight% % % % ~ %Influence of Gap Grading and Aggregate SizePC-100-3/8-0 100 0 0 0 0.30 0.00PC-100-#4-0 0 100 0 0 0.30 0.00PC-100-#8-0 0 0 100 0 0.30 0.00Influence of Blending #8 and #4 AggregatesPC-100-#8-0 0 0 100 0 0.30 0.00PC-75#8-25#4-0 0 25 75 0 0.30 0.00PC-50#8-50#4-0 0 50 50 0 0.30 0.00PC-25#8-75#4-0 0 75 25 0 0.30 0.00PC-100-#4-0 0 100 0 0 0.30 0.00Influence of Blending #8 and 3/8" AggregatesPC-100-#8-0 0 0 100 0 0.30 0.00PC-75#8-25-3/8-0 25 0 75 0 0.30 0.00PC-50#8-50-3/8-0 50 0 50 0 0.30 0.00PC-25#8-75-3/8-0 75 0 25 0 0.30 0.00PC-100-3/8-0 100 0 0 0 0.30 0.00Influence of Blending #4 and 3/8" AggregatesPC-100-#4-0 0 100 0 0 0.30 0.00PC-75#4-25-3/8-0 75 25 0 0 0.30 0.00PC-50#4-503/8-0 50 50 0 0 0.30 0.00PC-25#4-753/8-0 25 75 0 0 0.30 0.00PC-100-3/8-0 100 0 0 0 0.30 0.00Influence of Sand ContentPC-100-#4-0 0 100 0 0 0.30 0.00PC-95#4-5Sand-0 0 97 0 3 0.30 0.00PC-97.5#4-2.5Sand-0 0 95 0 5 0.30 0.00PC-92.5#4-7.5Sand-0 0 92 0 8 0.30 0.00Influence of Silica FumePC-100-#4-0 0 100 0 0 0.30 0.00PC-100-#4-06SF 0 100 0 0 0.30 0.06PC-100-#4-12SF 0 100 0 0 0.30 0.12Using A Simple Method for Screening MixturesLoudspeakerHollowCylinderMicrophone #1Microphone #2SoundWavesTest SpecimenIncomingSoundReflectedSoundImpedance TubeSampleAbsorption in 150 mm Thick Specimens (Typ. Conc. 0.05)200 400 600 800 1000 1200 1400 1600Frequency (Hz)0.00.20.40.60.81.0Absorption Coefficient 25% #8, 75% #425% #8, 75% 3/8"100% 3/8"Typical Impedance Tube Results200 400 600 800 1000 1200 1400 1600Frequency (Hz)0.00.20.40.60.81.0Absorption Coefficient 100% #8, 0% 3/8"75% #8, 25% 3/8"50% #8, 50% 3/8" 25% #8, 75 % 3/8"0% #8, 100% 3/8"200 400 600 800 1000 1200 1400 1600Frequency (Hz)0.00.20.40.60.81.0Absorption Coefficient 100% #4100% #4, 6% SF100% #4, 12% SF200 400 600 800 1000 1200 1400 1600Frequency (Hz)0.00.20.40.60.81.0Absorption Coefficient 100% #4, 0% Sand100% #4, 2.5% Sand100% #4, 5.0% Sand100% #4, 7.5% Sand200 400 600 800 1000 1200 1400 1600Frequency (Hz)0.00.20.40.60.81.0Absorption Coefficient 100% 3/8"100% #4100% #8Influence of Specimen Length0 400 800 1200 1600Frequency (Hz)0.000.200.400.600.801.00Absorption Coefficient (%) 75 mm Specimen150 mm Specimenlcnf peak⋅⋅=4lc2How Do We Gain an Idea of What the Internal Porosity Looks Like12.5 mm25 mm25 mm25 mm25 mm37.5 mmSeal Sides and Add Low Viscosity EpoxyGoal: Separate Porosity IntoTotal and Accessible PorositySteps: Cut At Various Depths and ImageImage Processing Sample PreparationScanned ImageCropped to a Diameter of 2.75 in (550 Pixels)Epoxy Added and Specimen SectionedUsing DiamondBladed SawScanning Using aFlatbed ScannerImage Processing Determine Total PorosityScanned ImageCropped to a Diameter of 2.75 in (550 Pixels)Color Intensity Threshold Established (~ 150) To SeparateTotal Porosity (i.e., airand Epoxy Filled Space)Aggregate PorosityImage Cleaned White Pixels (Porosity)Counted = 72,641Divide By Total Pixels72,641/237463 = 30.6%Porosity is WhiteImage Processing Determine Inaccessible PorosityScanned ImageCropped to a Diameter of 2.75 in (550 Pixels)Separate Total Porosity into Accessible Porosity and Inaccessible PorosityColor the Surface of the Scanned ImageCropped to a Diameter of 2.75 in (550 Pixels)Epoxy Filled SpaceAir Filled Void Air Filled VoidEpoxy Filled SpaceAir Filled VoidImage Processing Determine Inaccessible PorosityColor Intensity Threshold Established (~ 70) To SeparateInaccessible Porosity (i.e., Air Filled Space)Image Cleaned Black Pixels (Porosity+Background) and Subtract BackgroundCounted = 225,08712,376/237463 = 5.2%30.6%-5.2% = 25.4% APColor the Surface of the Scanned ImageCropped to a Diameter of 2.75 in (550 Pixels)Air Filled VoidSaw ScratchesAggregate Size and Pore Size0 20 40 60 80 100Percentage of Larger Aggregates234563/8" & #4 (SR 2)#4 & #8 (SR 2)3/8" & #8 (SR 4)Characteristic Pore Size (mm)Characteristic Pore Size (mm)Flexural Strength10 20 30 40Total Porosity (%)2.02.42.83.23.64.0Flexural Strength (MPa)2 3 4 5Characteristic pore size (mm)22.42.83.23.64Flexural strength (MPa)Examples of Basic Trends0 25 50 75 100Percent Aggregate #4 (%)2.02.42.83.23.64.0Flexural Strength (MPa)#4 and #8 Aggregate Blend0.00 2.50 5.00 7.50 10.00Aggregate Size (mm)2.02.42.83.23.64.0Flexural Strength (MPa)100% 3/8" (9.5 mm)100% #4 (6.4 mm)100% #8 (3.2 mm)0.00 2.50 5.00 7.50 10.00Percent Fine Aggregate (%)2.02.42.83.23.64.0Flexural Strength (MPa)#4 and Fine Aggregate Blend0.00 3.00 6.00 9.00 12.00Percent Silica Fume Addition (%)2.02.42.83.23.64.0Flexural Strength (MPa)100% #4 Aggregate% Silica Fume By Weight of CementInspiration for Trying Multi-Layer Systems0.000.100.200.300.400.500.600.700.800.901.00100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600Frequency (Hz)Absorption Coefficient S1R1 - Abs_Coeff_%S1R2 - Abs_Coeff_%S2R1 - Abs_Coeff_%S2R2 - Abs_Coeff_%Average_Abs_Coeff_%Series AB - 75% #8's, 25% #4 - Tested 2/2/01Interesting TrendIncreasing AbsorptionAt Higher FrequenciesMulti-Layer Pavements#8’s#4’s10 15 20 25 30 35Porosity (%)1501251007550250Specimen Depth (mm)Total Accessible75% #8 and 25% #4Modeling Sound Absorption and Porosity1111−++=nDonZZzZ22 )()1(4oooooocMcRcRρρρα++=Using the Model to Determine the Optimal Pore Geometries• Optimal Dp/Da value for each Dp where α is max.– High Dp/Da: small aperture size, more energy reflected– Small Dp/Da: large aperture size, air trapped in pores2 4 6 8 10 12 14 16Dp/Da00.20.40.60.81Maximum absorption coefficient (α)Dp = 2 mmDp = 3 mmDp = 5 mmAperturePoreWater Permeability300 mm150mmGraduated CylinderSpecimen95 mm0.16 0.18 0.2 0.22 0.24 0.26Porosity00.00010.00020.00030.00040.0005Intrinsic Permeability (m2)Characterizing the Pore Structure• Electrical Impedance Spectroscopy• Characterization of pore connectivity andtortuosityPermeability and Conductivityφσσβ0=0σσ Normalized conductivityφ Porosity0 0.01 0.02 0.03 0.04 0.05Normalized conductivity (S/m)0.00010.00020.00030.00040.0005Intrinsic permeability (m2)Controlled Testing Road SurfaceSpeeds of up to 30 mphTireMeasure Sound Generated By Tire/Pavement InteractionTesting FrameSimulated Suspension24 in8-16 in13.5-15 feetSummary and Conclusions• Porous Concrete May Have Benefits – Sound Absorption and Drainage• The “Structure of these Materials Influence Performance” (Impedance Tube, Porosity, Strength, Permeability)• Blended Systems Appear to Show Optimal Performance• Modeling Appears to Have A Promise to Help Us Optimize the Properties We Want• Durability Testing is Beginning for F-T Climates

Porous Concrete Pavement and Concrete Pavement with Inclusions

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Porous Concrete Pavement and Concrete Pavement with Inclusions

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