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From page 38... ... was on identifying those NDT devices that can consistently and accurately determine when changes occur within the construction process, as well as confirm the assumptions used in pavement structural design. 2.1 Identification of Material Anomalies and Differences The testing under the Part A field evaluation was to confirm that the NDT technologies can identify differences in construction quality of unbound pavement layers and HMA mixtures. Read the entire page →
From page 39... ... Project Identification HMA Sections Description of Differences Along the Project TH-23 HMA Base; Spicer, Minnesota Section 2, Middle or Northeast Section QA records indicate lower asphalt content in this area -- asphalt content was still within the specifications. Section 2, Middle; All Lanes QA records indicate higher asphalt content in this area, but it was still within the specifications. Read the entire page →
From page 40... ... Area Lanes B,C 29.16 124.1 10.1 35.7 19.01 4.77 TH-23 SiltSand-Gravel Mix Embankment Lane A is stronger No No Yes Yes No No Lane A 10.29 123.2 25.4 33.9 21.60 24.2 Lane B 9.30 123.0 25.5 34.7 20.95 27.8All lanes Lane C 9.78 123.8 24.77 33.3 20.74 21.2 No Planned Difference Yes Yes Yes Yes Yes No Area 1,2 9.74 123.5 26.3 36.5 20.64 24.6 All areas Area 3 9.88 123.1 22.3 28.9 22.01 24.1 SH-130 Granular Improved Embankment No Planned Difference Yes Yes No No Yes Yes Lanes A,B 9.37 129.8 14.4 100.4 42.05 16.75 South & Middle Sections Lane C 10.62 129.8 10.8 50.7 21.33 8.31 Lane C is weaker No No Yes Yes Yes Yes So. Area Lanes A,B 9.79 129.9 15.0 110.7 46.45 19.38 Middle Section Lane C 10.38 129.8 9.8 28.0 18.55 7.95 All other areas 9.54 129.8 12.8 75.0 33.14 12.31 Lane C, middle section, is weaker No No Yes Yes Yes Yes TH-23 Crushed Aggregate Base Lanes A & B, south section, are stronger No No Yes Yes Yes Yes Lane 4 11.57 148.2 35.1 117.4 34.31 18.53 All areas Lanes 1,2,3 11.95 147.4 47.9 198.6 50.29 46.46 US-280 Crushed Stone Base Lane 4 is weaker No No Yes Yes Yes Yes NOTE: The results in the shaded or black cells represent areas where the hypothesis was rejected based on a 95 percent confidence interval, and are inconsistent with the construction records and experimental plan. Read the entire page →
From page 41... ... 2.1.2 HMA Layers Table 18 contains the results of checking the hypotheses for the HMA layers. The shaded cells in Table 18 designate those 41 NDT DeviceProject Hypothesis PSPA FWD GPR PQI Section 2 Lanes A,B 285.0 568.9 6.18 149.9 Sections 1,3 Lanes A,B 262.0 405.4 10.14 146.6 Section 2 is Stronger or Stiffer Yes Yes Yes Yes Lane C Section 2,3 288.5 NA 8.51 141.6 Lane C Sections 1 215.4 NA 8.62 140.3 I-85 SMA Overlay Section 1 is Weaker/Less Dense Yes NA No Yes Section 2 All Lanes 454.4 NA 7.04 145.2 Sections 1,3 All Lanes 489.8 NA 6.64 146.6 Section 2 is Weaker Yes NA Yes Yes Section 4 All Lanes 499.5 NA NA 143.9 TH-23 HMA Base No Planned Difference; Sections 1,3,4 Yes NA NA No Initial Sections Section 1 499.9 203.3 7.03 148.0 Supplemental Sections Sections 1,2 555.0 877.2 5.50 140.4US-280HMA Base Supplemental Area is Stronger/Denser Yes Yes Yes No Section 1 All Lanes 499.9 203.3 7.03 148.0 Section 2 All Lanes 423.9 125.9 6.81 154.5 Section 1 is Stronger/Denser Yes Yes No No Longitudinal Joints Confined Joint 305.8 125.5 7.70 145.7 Joints are Less Dense/Weaker Yes No Yes Yes Segregated Areas All Lanes 329.9 144.5 7.28 147.1 US-280 HMA Base, Initial Sections Segregated Areas are Less Dense/Stiff Yes No No Yes Section 1 All Lanes 559.8 569.0 5.55 140.4 Section 2 All Lanes 550.2 1185.3 5.45 140.5 No Planned Difference Yes No Yes Yes Longitudinal Joints All Lanes 596.0 379.0 5.78 135.8 Joints are Les Dense/Weaker No Yes No Yes Segregated Areas All Lanes 391.3 707.0 5.64 136.6 US-280 HMA Base, Supplemental Sections Segregated Areas are Less Dense/Stiff Yes No No Yes Section 1 All Lanes 384.9 NA 5.95 126.5 Section 2 All Lanes 292.6 NA 5.61 124.0 Section 3 All Lanes 461.7 NA NA 125.1 Section 2 is Weaker/Less Dense Yes NA Yes Yes Joints All Lanes 297.5 NA 5.08 118.8 I-35/SH-130 HMA Base Joints are Less Dense/Stiff Yes NA No Yes Table 18. Read the entire page →
From page 42... ... 2.2 Estimating Target Modulus Values Laboratory measured modulus of a material is an input parameter for all layers in the MEPDG. Resilient modulus is the input for unbound layers and soils, while the dynamic modulus is used for all HMA layers. Read the entire page →
From page 43... ... Figure 17-1. Comparison of laboratory resilient modulus and the elastic modulus values estimated with different NDT technologies and devices. Read the entire page →
From page 44... ... 127 127.5 128 128.5 129 129.5 130 130.5 131 3.8 4.8 5.8 7 8 9 10 Moisture Content, US-280 Crushed Stone, percent D ry D en si ty , p cf 0 20 40 60 80 100 120 140 Se is m ic M od ul us , k si Dry Density Seismic Modulus Poly. (Seismic Modulus) Read the entire page →
From page 45... ... Adjustment factors or ratios applied to the NDT modulus values to represent laboratory conditions or values at low stress states; Part A projects. Project & Materials Area Dry Density, pcf Moisture Content, % Percent Maximum Density, % Laboratory Resilient Modulus, ksi Before IC Rolling Section 1, Lanes B,C,D 103.0 21.6 0.91 2.5 I-85 Low Plasticity Clay Embankment After IC Rolling Section 1, Lanes B,C,D 108.0 16.9 0.96 4.0 NCAT; Oklahoma High Plasticity Clay 96.7 21.3 0.97 6.9 NCAT; South Carolina Crushed Granite Base 130.0 4.7 0.94 14.3 South Section Lanes A,B 121.0 8.2 0.98 16.0 TH-23 Embankment, Silt-SandGravel Mix North Section Lane B,C 122.4 9.1 1.00 16.4 US-2 Embankment; Soil-Aggregate Mix 123.1 12.1 0.96 19.0 NCAT; Missouri Crushed Limestone Base 124.4 9.0 0.96 19.2 SH-21 High Plasticity Clay Area 1, with IC rolling Lanes A,B 107.3 18.4 0.99 26.8 Middle Area Lane B 139.4 4.3 1.04 24.0 TH-23 Crushed Aggregate Base South Area All Lanes 141.1 4.2 1.03 24.6 US-53 Crushed Aggregate Base, Type 304 136.0 9.1 1.01 27.5 NCAT; Florida Limerock Base 110.5 13.4 0.95 28.6 US-2 Class 5 Crushed Aggregate Base 134.4 5.9 0.95 32.4 SH-130 Improved Granular Sections 2, 3 Lanes A,B 128.7 9.1 1.05 35.3 US-280 Crushed Stone Areas 1,2,3 150.6 3.2 1.01 48.4 NOTES: Resilient modulus values for the fine-grained soils and embankments are for a low confining pressure (2 psi) Read the entire page →
From page 46... ... Sect., Lane A 17.0 22.0 51.7 18.5 4.7 No IC Rolling 22.0 19.6 23.6 11.9 -- - SH-21 Subgrade High Plasticity Clay After IC Rolling 26.8 22.9 27.1 8.8 9.6 Middle Sect., Lane C 19.5 21.6 28.0 18.6 8.0 North Section, All Lanes; Middle Section Lanes A, B 24.6 28.2 79.3 33.1 12.3 TH-23 Base Crushed Aggregate Base South Section, Lanes A, B 26.0 33.0 110.7 46.4 19.4 Section 3 34.5 19.4 33.3 20.7 24.1 SH-130 Improved Embankment Granular Sections 1, 2 35.3 26.4 34.3 21.3 24.6 Area 4 40.0 35.1 117.4 34.3 18.5 US-280 Base Crushed Stone Areas 1, 2, 3 48.4 47.9 198.6 50.3 46.5 NOTES: * The repeated load resilient modulus values measured in the laboratory, but corrected to the actual dry density and moisture content measured for the specific section, in accordance with the LTPP procedure and regression equations. Read the entire page →
From page 47... ... γ (4) 47 Project Material Maximum Dry Unit Weight, pcf Optimum Water Content, % Average Dry Density, pcf Average Water Content, % NCAT, Oklahoma High Plasticity Clay 99.9 21.8 96.7 21.3 SH-21, TX High Plasticity Clay 108.0 21.9 107.3 18.4 Low Plasticity Soil; Pre-IC 107.98 16.9 I-85, AL Low Plasticity Soil; Post-IC 112.7 13.1 107.98 16.9 SH-130, TX Improved Granular Embankment 122.0 9 123.3 8.32 Silt-Sand-Gravel Mix – South Area 122.77 8.69 TH-23, MN Silt-Sand-Gravel Mix – North Area 122.6 12 123.80 7.87 US-2, ND Soil-Aggregate,Embankment 128.0 9.0 123.1 12.1 NCAT, FL Limerock Base 116.1 12.5 110.5 13.4 CR-103 Caliche Base 127.5 10.0 125.0 9.5 NCAT, MO Crushed Limestone 130.0 10.0 124.4 9.0 TH-23, MN Crushed Aggregate Base 135.3 7.8 129.82 4.3 US-53, OH Crushed Aggregate Base 134.1 8.5 136.0 9.1 NCAT, SC Crushed Granite Base 138.1 5.0 130.0 4.7 US-2, ND Crushed Gravel Base 141.1 6.0 134.4 5.9 US-280, AL Crushed Stone Base 148.5 6.2 147.58 3.9 NOTE: The maximum dry density and optimum water content for most of the materials and layers were determined using AASHTO T 180. Read the entire page →
From page 48... ... 103, TX Caliche Base -- - 32.3 1.214 -- - 1.436 NCAT, SC Crushed Granite 14.3 36.1 0.947 0.156 -- - NCAT, MO Crushed Limestone 19.2 40.9 0.747 0.198 -- - Crushed Stone, Middle 24.0 29.9 0.851 0.303 0.725 TH-23, MN Crushed Stone, South 26.0 35.6 0.788 0.235 0.560 US-53, OH Crushed Stone 27.5 38.3 1.170 0.449 0.862 NCAT, FL Limerock 28.6 28.1 0.574 0.324 0.619 US-2, ND Crushed Aggregate 32.4 39.8 1.884 0.623 1.129 US-280, AL Crushed Stone 48.4 49.3 1.010 0.244 0.962 Average Ratios for Aggregate Base Materials 1.021 0.316 0.899 Overall Average Values 0.942 0.422 1.084 NOTES: 1. The adjustment ratio is determined by dividing the resilient modulus measured in the laboratory at a specific stress state by the NDT estimated modulus. Read the entire page →
From page 49... ... This HMA base mixture is a very stiff mixture in the 0 0.5 1 1.5 2 0 20 40 60 80 100 Percent Passing Number 200 Sieve, % A dju stm en t R ati o f or G eo G au ge Fine-Grained Soil Aggregate-Soil Mixture Crushed Aggregate Base (a) GeoGauge. Read the entire page →
From page 50... ... Elastic modulus values estimated from NDT devices, without any adjustments, in comparison to dynamic modulus values measured in the laboratory. Ratio or Adjustment Factor Project/Mixture DynamicModulus, ksi PSPA FWD I-85 AL, SMA Overlay 250 1.055 0.556 TH-23 MN, HMA Base 810 1.688 NA US-280 AL, HMA Base; Initial Area 650 1.407 3.939 US-280 AL, HMA Base; Supplemental Area 780 1.398 2.516 I-35/SH-130 TX, HMA Base 1,750 5.117 3.253 I-75 MI, Dense-Graded Type 3-C 400 0.919 NA I-75 MI, Dense-Graded Type E-10 590 0.756 NA US-47 MO, Fine-Graded Surface 530 1.158 NA US-47 MO, Coarse-Graded Base Mix 420 0.694 NA I-20 TX, HMA Base, CMHB 340 0.799 NA US-53 OH, Coarse-Graded Base 850 1.275 NA US-2 ND, Coarse-Graded Base, PG58-28 510 1.482 NA NCAT SC, PG67 Base Mix 410 0.828 NA NCAT FL, PG67 Base Mix 390 0.872 NA NCAT FL, PG76 Base Mix 590 1.240 NA NCAT AL, PG76 with RAP and Sasobit 610 1.3760 NA NCAT AL, PG76 with RAP and SBS 640 1.352 NA NCAT AL, PG67 with RAP 450 0.881 NA Overall Average Ratio or Adjustment Factor 1.128 2.566 NOTES: 1. Read the entire page →
From page 51... ... On the average, the PSPA can be used to estimate the dynamic modulus measured in the laboratory HMA mixtures, while the FWD was found to be extremely variable. The PSPA ratios are variable, but that variability is less than the ratios for the unbound materials. Read the entire page →
From page 52... ... 0 10 20 30 40 50 60 80 90 70 0 10 20 30 40 50 60 Mean Elastic Modulus, LWD, ksi Co ef fic ie nt o f V ar ia tio n, % Figure 24. Coefficient of variation versus the mean modulus calculated from the LWD deflections. Read the entire page →
From page 53... ... The DSPA was also placed in different directions relative to the roller direction for measuring modulus; the other NDT devices do not have this capability -- only an equivalent or average modulus value is reported for all directions. Figure 28 compares the difference between the modulus values parallel and perpendicular to the roller's direction to the modulus measured parallel to roller direction. Read the entire page →
From page 54... ... Project Identification Area A B C D Mean, pcf 107.92 108.9 108.6 107.7 I-85 Embankment, Silty Clay; Section 1, Before IC Rolling COV, % 1.3 0.5 1.1 1.7 Mean, pcf 107.2 107.5 108.9 107.2 I-85 Embankment, Silty Clay; Section 2, Before IC Rolling COV, % 0.8 0.8 1.1 1.9 Mean, pcf 108.1 108.2 108.5 108.4 I-85 Embankment, Silty Clay; Section 1, After IC Rolling COV, % 1.0 0.5 0.7 0.3 Mean, pcf 107.4 107.7 108.0 107.6 I-85 Embankment, Silty Clay; Section 2, After IC Rolling COV, % 0.5 0.5 0.8 1.3 Mean, pcf 123.9 123.7 124.4 -- - TH-23 Embankment, Silt-SandGravel Mix; North Section COV, % 0.4 0.1 1.0 -- - Mean, pcf 122.5 122.9 122.9 -- -TH-23 Embankment, Silt-SandGravel Mix; South Section COV, % 1.8 1.8 0.8 -- Mean, pcf 123.7 123.7 124.9 -- - SH-130 Improved Embankment; Section 1 COV, % 0.3 0.1 0.6 -- - Mean, pcf 122.6 123.1 122.7 -- - SH-130 Improved Embankment; Section 2 COV, % 2.0 2.0 0.8 -- - Mean, pcf 123.3 122.3 123.7 SH-130 Improved Embankment; Section 3 COV, % 1.4 0.1 0.2 Mean, pcf 129.9 129.8 129.8 -- - TH-23 Crushed Aggregate; North Section COV, % 0 0 0 -- - Mean, pcf 129.8 129.8 129.8 -- -TH-23 Crushed Aggregate; Middle Section COV, % 0 0 0 -- Mean, pcf 129.8 129.9 129.8 -- - TH-23 Crushed Aggregate; South Section COV, % 0.1 0.1 0 -- - Mean, pcf 147.4 US-280 Crushed Stone; Section 1 COV, % 0.7 Mean, pcf 148.8 US-280 Crushed Stone; Section 2 COV, % 0.3 Mean, pcf 145.9 US-280 Crushed Stone; Section 3 COV, % 0.5 Mean, pcf 148.2US-280 Crushed Stone; Section 4 COV, % 0.3 Note: The shaded cells designate those areas with anomalies (refer to Table 14) ; the black cells denote the weaker areas, while the gray cells denote the stronger areas tested within a specific project. Read the entire page →
From page 55... ... sections; however, weather Project Identification Area A B C D Mean, % 16.9 16.8 16.9 16.9 I-85 Embankment, Silty Clay; Section 1, Before IC Rolling COV, % 0.8 0.3 0.3 1.0 Mean, % 16.9 16.9 16.8 17.0 I-85 Embankment, Silty Clay; Section 2; Before IC Rolling COV, % 0.7 0.3 0.3 1.5 Mean, % 16.9 16.9 16.9 16.9 I-85 Embankment, Silty Clay; Section 1, After IC Rolling COV, % 0.5 0.3 0.4 0 Mean, % 17.0 16.9 16.9 16.9 I-85 Embankment, Silty Clay; Section 2, After IC Rolling COV, % 0.5 0.3 0 0.7 Mean, % 8.0 8.0 7.6 TH-23 Embankment, Silt-SandGravel Mix; North Section COV, % 5.1 1.1 11.9 Mean, % 9.8 8.7 7.6TH-23 Embankment, Silt-SandGravel Mix; South Section COV, % 7.5 7.3 15.8 Mean, % 8.1 8.05 7.23 SH-130 Improved Embankment; Section 1 COV, % 4.4 1.2 6.8 Mean, % 8.85 8.43 8.7 SH-130 Improved Embankment; Section 2 COV, % 19.8 21.6 8.4 Mean, % 8.35 9.1 8.05 SH-130 Improved Embankment; Section 3 COV, % 14.4 1.6 0.9 Mean, % 4.26 4.28 4.34 TH-23 Crushed Aggregate; North Section COV, % 1.3 1.0 2.1 Mean, % 4.24 4.28 4.30TH-23 Crushed Aggregate; Middle Section COV, % 1.3 2.0 1.6 Mean, % 4.18 4.18 4.38 TH-23 Crushed Aggregate; South Section COV, % 3.9 3.9 1.0 Mean, % 3.92 US-280 Crushed Stone; Section 1 COV, % 3.1 Mean, % 4.18 US-280 Crushed Stone; Section 2 COV, % 2.9 Mean, % 3.77 US-280 Crushed Stone; Section 3 COV, % 2.9 Mean, % 4.06US-280 Crushed Stone; Section 4 COV, % 2.6 Note: The shaded cells designate those areas with anomalies (refer to Table 14) ; the black cells denote weaker areas, while the gray cells denote the stronger areas tested within a specific project. Read the entire page →
From page 56... ... 2.3.3 Summary Tables 32, 33, and 34 contain the statistical analyses of the NDT devices included in the field evaluation projects. This Project Identification Area A B C D Mean 15.38 15.79 14.29 15.19 I-85 Embankment, Silty Clay; Section 1, Before Rolling COV, % 17.8 23.3 53.6 25.7 Mean 13.91 17.47 16.82 16.38 I-85 Embankment, Silty Clay; Section 2, Before IC Rolling COV, % 29.0 20.5 30.7 24.1 Mean 20.37 21.23 21.61 23.23 I-85 Embankment, Silty Clay; Section 1, After IC Rolling COV, % 15.8 10.6 15.0 12.6 Mean 19.13 23.75 23.77 25.36 I-85 Embankment, Silty Clay; Section 2; After IC Rolling COV 10.2 10.7 17.6 8.4 Mean 23.004 13.468 19.334 -- -TH-23 Embankment, Silt-SandGravel Mix; South Section COV, % 11.3 7.0 14.4 -- Mean 20.324 34.438 23.882 -- - TH-23 Embankment, Silt-SandGravel Mix; North Section COV, % 22.2 32.7 22.7 -- - Mean 9.225 10.00 7.65 -- - SH-130 Improved Embankment; Section 1 COV 33.1 42.3 42.9 -- - Mean 12.875 8.875 9.825 -- - SH-130 Improved Embankment; Section 2 COV 90.3 47.4 20.1 Mean 8.775 9.025 11.85 SH-130 Improved Embankment; Section 3 COV, % 51.5 50.8 48.7 -- - Mean -- - 8.796 10.042 -- - TH-23 Crushed Aggregate; North Section COV, % -- - 1.6 5.4 -- - Mean -- - 8.950 10.87 -- -TH-23 Crushed Aggregate; Middle Section COV, % -- - 6.1 10.9 -- Mean -- - 9.792 10.378 -- - TH-23 Crushed Aggregate; South Section COV, % -- - 8.2 4.3 -- - Mean 11.723 US-280 Crushed Stone; Section 1 COV, % 8.3 Mean 12.222 US-280 Crushed Stone; Section 2 COV, % 11.4 Mean 11.919 US-280 Crushed Stone; Section 3 COV, % 7.3 Mean 11.569US-280 Crushed Stone; Section 4 COV, % 7.0 Notes: The shaded cells designate those areas with anomalies (refer to Table 14) Read the entire page →
From page 57... ... 2.4.1 NDT Modulus Comparisons Figure 34 compares the NDT modulus values used to identify areas with physical differences in the unbound layers, except that the NDT values have been adjusted to laboratory conditions with the adjustment ratios listed in Table 24. Figure 34(a) Read the entire page →
From page 58... ... 0 10 20 30 40 50 60 Laboratory Resilient Modulus, ksi 0 10 20 30 40 50 60 A dju ste d E las tic M od ulu s fro m N DT D ev ic es , k si DCP, Fine-Grained DCP, Coarse-Grained Line of Equality LWD, Fine-Grained LWD, Coarse-Grained Figure 30. Laboratory resilient modulus versus adjusted NDT modulus. Read the entire page →
From page 59... ... • DSPA: The DSPA can significantly overestimate the laboratory measured resilient modulus values. The US-280 crushed stone base was dry or significantly below the optimum water content during testing in some areas. Read the entire page →
From page 60... ... Modulus, ksi Density, pcf Air Voids, % Fluids Content NDT Devices with Good Success Rates Based on Modulus or Volumetric Properties; see Section 2.1.1 GeoGauge NA 4.9 NA NA NAFine-Grained Soils DSPA NA 8.8 NA NA NA GeoGauge NA 4.9 NA NA NACoarse-Grained Soils & Aggregate Base DSPA NA 8.8 NA NA NA PSPA NA 150 NA NA NAHMA Mixtures PQI & PT NA NA 3.4 NA NA NDT Devices with Poor Success Rates Based on Modulus or Volumetric Properties; see Section 2.1.2 DCP NA 7.4 NA NA NA LWD NA 11.6 NA NA NA GPR NA NA NA NA NAFine-Grained Soils EDG NA NA 1.6 NA 0.4 DCP NA 7.4 NA NA NA LWD NA 11.6 NA NA NA GPR 1.5 NA 6.7 NA NA Coarse-Grained Soils & Aggregate Base EDG NA NA 2.0 NA 0.4 FWD NA 170.5 NA NA NA GPR; Single 0.49 NA NA 0.8 NAHMA GPR; Multiple 0.55 NA 3.1 0.4 0.36 NOTES: 1. The precision tolerance for the modulus estimating devices is based on the adjusted modulus values that have been adjusted to laboratory conditions. Read the entire page →
From page 61... ... The pooled standard deviations for the modulus estimating devices are based on the adjusted modulus values that have been adjusted to laboratory conditions. Read the entire page →
From page 62... ... This observation suggests that there are different properties affecting the EDG and GPR results -- none of which could identify the physical differences at a reasonable success rate. • Figure 37 compares the GPR dielectric values to the dry density measured with different devices -- the EDG, nuclear density gauges, and sand-cone tests. Read the entire page →
From page 63... ... GPR dielectric values versus dry densities measured with nuclear and non-nuclear density gauges. 90 95 100 105 110 115 120 125 130 135 140 90 95 100 105 110 115 120 125 130 140135 Dry Density, EDG, pcf Dr y De ns ity , Nu cl ea r De ns ity G au ge Series1 Line of Equality Figure 38. Read the entire page →
From page 64... ... Figure 39. Air voids measured with the GPR versus densities measured with the PQI and nuclear density gauges for different HMA mixtures. Read the entire page →
From page 65... ... Figure 42 compares the dry densities measured with the EDG and modulus values estimated from the GeoGauge and DCP. The NDT modulus increases with increasing dry density over a wide range of material types, which is consistent with previous experience. Read the entire page →
From page 66... ... NDT modulus values versus dry density measured by the EDG. 0 10 20 30 40 50 60 0 10 20 30 40 50 GPR Dielectric Values R es ili en t M od ul us , G eo G au ge , ks i Figure 43. Read the entire page →
From page 67... ... PSPA modulus versus PQI density of HMA mixtures. 0 2 4 6 8 10 12 14 16 100 300200 400 500 600 700 PSPA Seismic Modulus, ksi G PR A ir Vo id s, p er ce nt TH-23 Base SMA Overlay US-280 Base, InitialUS-280 Base, Supp. Read the entire page →
From page 68... ... • Figure 50 presents data collected during the compaction of a Missouri crushed limestone base material. The first roller pass within this figure is after the material had been preliminarily compacted from other construction equipment and roller passes. Read the entire page →
From page 69... ... 2.5.1.2 HMA Mixtures and Layers Overall, the PSPA and PaveTracker were successful in monitoring the build up of modulus and density with the number of roller passes for the HMA layers placed within the field evaluation projects. Some examples follow. Read the entire page →
From page 70... ... 40 45 50 55 60 65 70 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Number of Roller Passes D SP A M od ul us , k si 6 7 8 9 10 11 DSPA Modulus GeoGauge Modulus 5 6 7 8 9 10 0 4 2 6 8 10 12 14 Number of Roller Passes G eo G au ge M od ul us , k si South Carolina Crushed Granite Figure 51. Modulus-growth relationships for a South Carolina crushed granite base material for two different areas. Read the entire page →
From page 71... ... • Figure 53 presents density data collected on a Missouri HMA base mixture that was not tender, but was rolled within the temperature sensitive zone. The first pass of the rubber-tired roller increased the density, but additional passes of that roller significantly decreased the density of the mat. Read the entire page →
From page 72... ... 145 147 149 151 153 155 157 159 161 163 165 0 2 41 3 5 Number of Roller Passes D en si ty M ea su re d w ith P av eT ra ck er , p cf 170 180 190 200 210 220 230 Te m pe ra tu re o f M ix tu re , °° F Mat Density Joint Density Mat Temperature Joint Temperature 136 138 140 142 144 146 148 150 152 154 0 2 41 3 5 Number of Roller Passes H M A M at D en si ty , p cf 0 50 100 150 200 250 M at T em pe ra tu re , °° F PaveTracker Density Nuclear Gauge Density Temperature Figure 52. Typical density-growth curve measured with PaveTracker and nuclear density gauge for the Missouri US-47 project. Read the entire page →
From page 73... ... • Use of different GeoGauges and operators resulted in some bias that was modulus dependent for some materials; more bias was exhibited for the higher modulus values or stiffer material. Material specific calibration or adjustment factors should be determined and used for each material tested (see Table 24) Read the entire page →
From page 74... ... • Three to five repeat measurements were made at each test point with the NDT devices, with the exception of the DCP. -- The LWD exhibited low standard deviations that were less dependent on material stiffness with a pooled standard deviation less than 0.5 ksi. Read the entire page →
From page 75... ... One driver was used for all testing with the GPR. • The COV was used to compare the normalized dispersion measured with different NDT devices. Read the entire page →
From page 76... ... After adjusting for laboratory conditions, all NDT devices that estimate resilient modulus resulted in low residuals (laboratory resilient modulus minus the NDT elastic modulus) Read the entire page →
From page 77... ... • The PSPA moduli were comparable to the dynamic moduli measured in the laboratory on test specimens compacted to the in-place density at a loading frequency of 5 Hz and the in-place mixture temperature, with the exception of one mixture -- the US-280 supplemental mixture. In fact, the overall average ratio or adjustment factor for the PSPA was close to unity (1.1) Read the entire page →
From page 78... ... However, based on the results obtained, the ability to provide uniform compaction was verified, and the rollers are believed to be worth future investments in monitoring the compaction of HMA mixtures. 2.6.3 Limitations and Boundary Conditions The following lists the limitations and boundary conditions observed during the field evaluation for the NDT devices suggested for QA application on an immediate, effective, and practical basis. Read the entire page →
From page 79... ... -- The results from these non-nuclear density gauges can be dependent on the condition of the layer's surface -- wet versus dry conditions. It is recommended that the gauges be used on relatively dry surfaces until additional data become available relative to this limitation. Read the entire page →

From page 38...

... was on identifying those NDT devices that can consistently and accurately determine when changes occur within the construction process, as well as confirm the assumptions used in pavement structural design. 2.1 Identification of Material Anomalies and Differences The testing under the Part A field evaluation was to confirm that the NDT technologies can identify differences in construction quality of unbound pavement layers and HMA mixtures.