Proposed AASHTO Practice and Tests for Process Control and Product Acceptance of Asphalt-Treated Cold Recycled Pavements (2021) / Chapter Skim
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Chapter 3 - Findings and Applications
Chapter 3 - Findings and Applications
Pages 25-113
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From page 25... ...
This work was completed The moisture content of the recycled layer is most often by reviewing the available literature, conducting a review measured using a nuclear density gauge or collecting a sample of agency specifications, and conducting an online stake- from the field for analysis in the laboratory by oven drying. holder survey.
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From page 26... ...
A handheld capaci- applied during the test. The authors point out that the zone tance sensor and a portable time-domain reflectometry unit of influence from LWD testing may extend well beyond the were used to assess the moisture content, along with an SSG depth of the recycled layer, especially for thinner applicaand LWD to assess the stiffness and measure the modulus of tions.
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From page 27... ...
Its use as part of a process control or quality assurance completely the stiffness properties of the recycled layer in a program could be expanded if the test was standardized. multilayered pavement structure, as described by Diefenderfer Proof rolling can effectively identify deficient material issues et al.
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From page 28... ...
The rubber hose abrades Using Solventless Emulsion that cold recycled materials shall the surface of the CIR specimen, and mass loss is measured. be assessed for release to traffic by using the results of the This test is designed for a laboratory setting, but an alter shear vane and Marshall field tests (Utah DOT 2007)
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From page 29... ...
VanFrank (2015) stated that the recycled layer was ready for traffic when a shear value of 30 ft-lb was obtained during 3.1.2 Stakeholder Survey field testing.
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Figures 3.8 through 3.10 show that Based on this finding, the research team focused on testing cement was the most prevalent active filler used by the survey that could be completed within the first 24 hours following respondents regardless of whether the stabilizing/recycling construction of a recycled layer. agent was emulsified or foamed asphalt.
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From page 31... ...
70% Foam 60% Emulsion 50% Percentage of Responses 40% 30% 20% 10% 0% Cement Lime Others Chemical Additive/Active Filler Figure 3.9. Active fillers used with CIR.
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of the test; and laboratory testing. The respondents rated the importance of • Applicability of results across CIR, CCPR, and FDR the following evaluation factors across three time frames materials.
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From page 33... ...
survey, the results based on the initial and short-term time frames are most relevant. 3.1.2.8 Tests Most Often Used for Suggested Properties 3.1.2.7 Preferred Location for Time Survey recipients were asked to identify those tests that were to Trafficking/Surfacing Test most often used for determining the deformation resistance, The survey recipients were also asked to identify their raveling resistance, density, stiffness, and curing initiation; preferred location for time to trafficking/surfacing test.
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From page 34... ...
deformation resistance, (b) raveling resistance, (c)
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From page 35... ...
Density – DCP Stiffness Nuclear density gauge CoreLok Curing initiation Moisture content by field drying (AASHTO T 255)
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all recycling processes, (b)
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From page 37... ...
100% 96% Percent of Specifications withTest 80% 69% 67% 64% Requirement 60% 40% 20% 18% 20% 7% 4% 2% 0% ITS DCP Density Curing Moisture Marshall Raveling Test/Proof Gradation Time Content Stability Stability Rolling Test Type Figure 3.17. Distribution of constructed quality characteristic for CIR.
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From page 38... ...
of reviewed agency specifications stated that both a cure 3.2 Candidate Tests time and moisture content requirement must be satisfied After the literature review and the stakeholder survey, prior to surfacing of the recycled layer. Of the specifications the research team worked to develop a list of potential (or that listed a required curing time, it ranged from 1 hour to candidate)
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From page 39... ...
. Summing the resistance, and moisture content.
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From page 40... ...
Gravimetric moisture ASTM D6780/ASTM content D7830/ASTM D6836 Nuclear gauge–based AASHTO T 310/ In-situ Confirm proper Gravimetric test moisture content ASTM D6938 moisture mixing/compaction prior to start of Low content Electromagnetic moisture content project ASTM D7830 moisture probe No, but research papers GPR exist Confirm correct Active filler Tarp or pan test amount of active filler Tarp or pan test No, but common practice Low content has been applied Recycling Probe Determine that design No, but common practice Probe, slit trench Low depth Slit trench requirements are met No, but common practice Check that Sieve analysis on appropriate grading mixture without ASTM C136/AASHTO Gradation Sieve analysis curve is achieved and Low recycling/ T 27 that there are no stabilizing agent oversize particles ASTM D3910 Typically used for with modification; measuring curing time can be done on ASTM D3910; can be in slurry mixtures. laboratory- easily modified and Curing time Cohesion tester Low Can be used to assess compacted adopted for laboratory and the time for opening samples or on field applications to traffic compacted mat in the field Using nuclear gauge Proxy test for Nuclear density ASTM D2950 assessing material (ASTM D2950)
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From page 41... ...
Gravimetric moisture ASTM D6780/ASTM content D7830/ASTM D6836 Nuclear gauge–based Confirm proper AASHTO T 310/ASTM In-situ Gravimetric test moisture content mixing/ D6938 moisture prior to start of Low compaction content project Electromagnetic moisture content ASTM D7830 moisture probe GPR No, but research papers exist Soil stiffness gauge ASTM D6758 (withdrawn in 2017) These stiffness tests have been ASTM E2583/ASTM Can be used to used primarily on E2835/draft specs from LWD determine degree research projects Stiffness TPF-5(285)
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From page 42... ...
Figure 3.21 Moisture content measurements using a Troxler Model 6760 shows a very low COV, with all values less than 6%. Figure 3.22 Moisture Probe were collected on fabricated test slabs at shows the variability of measurements on replicate slabs, with 2 and 72 hours of curing.
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Operator/data skill analysis level 7 low medium high 1 1 1 1 1 2 2 required spec plus APB spec but no Accuracy, precision, and bias of the test 3 no spec 1 3 3 1 1 1 1 statement APB statement Applicability to different materials 8 3 positive 2 positive 1 positive 1 1 1 1 1 1 1 (CIR, CCPR, FDR) score = sum of weighting factor 46 54 55 61 41 50 43 rank multiplied by usage level
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From page 44... ...
Operator/data skill analysis level 6 low medium high 1 2 2 1 2 required spec plus APB spec but no Accuracy, precision, and bias of the test 7 no spec 1 1 1 1 1 statement APB statement Applicability to different materials 8 3 positive 2 positive 1 positive 1 1 1 1 1 (CIR, CCPR, FDR) score = sum of weighting factor 46 46 47 44 60 rank multiplied by usage level
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From page 45... ...
Parameter Time Frame Property Score Density/compaction 41 Penetration, deformation, shear resistance/bearing tests 43 In-situ moisture 46 Initial Stiffness 50 Active filler content 54 Recycling depth 55 Gradation 61 Raveling resistance 44 In-situ moisture 46 Short term Stiffness 46 Penetration, deformation, shear resistance/bearing tests 47 Material strength 60 Longer term Stiffness 49
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From page 46... ...
Long-pin shear test 1, 3, 6, 24 In addition, when individual specimens were considered, Short-pin raveling test 1, 3, 6, 24 10 of 30 specimens had a lower stiffness with respect to Table 3.13. Specimen and mixture details for moisture content testing. Active Agent Actual Mix Stabilizing/Recycling Active Filler No.
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From page 47... ...
2-hour 72-hour 10 Emulsion, Emulsion, No Foam, No Foam, Cement Cement Cement Cement 8 Coefficient of Variation, % 6 4 2 0 0 2 4 6 8 10 12 14 16 18 20 Mixture ID Figure 3.22. Between-test slab variability for electromagnetic moisture device based on replicate specimens.
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From page 48... ...
with respect to recycling agent and presence of cement as an Table 3.14 shows the descriptive statistics of SSG stiffness active filler. The mean SSG stiffness increased when cement with respect to curing time.
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From page 49... ...
The SSG measurements indicuring time were possible only for the SSG and LWD tests. cated that a total of three mixtures had a lower stiffness with The variability of the SSG stiffness among mixture repli- an increase in curing time (i.e., a curing ratio of less than 1)
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as a function of curing (ANCOVA) at a confidence level of 95% was used to test time and recycling agent content with different recycling for significant factors on the SSG stiffness response among agent types.
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From page 51... ...
Recycling process 1 0.15 0.703 Table 3.17 shows the descriptive statistics of the LWD Recycling agent type 1 14.79 0.000 Curing time 1 14.05 0.000 modulus with respect to curing time. From Table 3.17, the Recycling agent content 6 3.22 0.005 mean LWD stiffness increased with respect to curing time, Notes: DF = degrees of freedom; bolding indicates as expected, showing the overall ability of the LWD test to that the p-value shows the source to be significant.
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From page 52... ...
Material Mean, Minimum, Quartile 1, Quartile 3, Maximum, Range, Interquartile Combination ksi ksi ksi ksi ksi ksi Range, ksi Emulsion, cement 25.6 4.6 9.3 35.8 36.1 31.5 26.5 Emulsion, no cement 21.3 9.7 13.6 25.6 33.1 23.5 12.0 Foam, cement 25.9 20.2 22.3 29.2 34.6 14.4 6.95 Foam, no cement 18.8 7.4 15.3 22.4 25.2 17.8 7.08 25 2-hour 20 Coefficient of Variation, % 72-hour 15 10 5 0 0 4 8 12 16 20 24 28 32 Specimens Figure 3.29. Within-specimen LWD variability in terms of a coefficient of variation. 2-hour 72-hour 50 Emulsion, Emulsion, Foam, Foam, Cement No Cement Cement No Cement 40 Coefficient of Variation, % 30 20 10 0 0 2 4 6 8 10 12 14 16 18 20 Mixture ID Figure 3.30. LWD variability among mixture replicates in terms of a coefficient of variation.
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From page 53... ...
that the LWD modulus was significantly varied (the p-value was less than 0.05) as a function of curing time and recycling 3.4.3.4 Additional LWD Tests agent content with different recycling agent types, the same factors identified in the analysis of the SSG stiffness.
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From page 54... ...
Higher Number of mixtures with statistically significant 1 3 Higher difference between the 2-hour vs. 72-hour tests Captured the effect of density Generally Generally Always Captured the effect of active filler presence Generally Generally Always Note: Highlights in columns denote which device better demonstrated the desired trend.
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From page 55... ...
For those mixtures incorporating was slightly higher than the average COV of 14.9% and 15.2% Table 3.22. Descriptive statistics of LWD modulus by curing time. Curing Mean, Minimum, Quartile Quartile Maximum, Range, Interquartile Time ksi ksi 1, ksi 3, ksi ksi ksi Range, ksi 1 hour 17.6 6.1 15.0 22.0 24.7 18.5 7.1 3 hours 18.2 8.7 14.7 22.4 28.5 19.8 7.7 6 hours 18.6 8.7 15.6 21.3 28.3 19.5 5.6 24 hours 22.2 11.4 18.6 26.6 34.3 22.8 8 Table 3.23. Descriptive statistics of LWD modulus by recycling agent and active filler type.
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From page 56... ...
Figure 3.33 shows that the There was an immediate reduction in the LWD modulus magnitude of the observed variability does not vary as a of the mixtures without cement, followed by an increase in function of the process type and recycling agent type or the modulus with increasing cure time. Similarly, the mixtures curing time, the same observation as with the 2- and 72-hour with cement tended to attain a higher LWD modulus.
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From page 57... ...
Curing time 1 9 0.000 Recycling agent content 6 9.25 0.000 Note: DF = degrees of freedom; bold/highlight = 3.4.4 Deformation Resistance p-value shows the source to be significant. Using the same test slabs that were used for stiffness test ing, deformation resistance testing was conducted using the LWD modulus were from Mixture 3 at all curing times, upper assembly of an MH for 16 different mixtures fabricated Mixture 12 at two curing times, Mixture 13 at a single curing from 12 sources, as shown in Table 3.12.
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From page 58... ...
8.0 20 Blows, 2 hrs Curing 7.0 20 Blows, 72 hrs Curing Average Penetrated Depth, mm 6.0 5.0 4.0 3.0 2.0 1.0 0.0 1 2 3 5-1 5-2 6 7 8 11 12 13 14 16 17-1 17-2 18 Mixture ID Figure 3.38. Average penetrated depths at 20 MH blows after 2- and 72-hour curing.
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From page 59... ...
from all evaluated mixtures at 2 and 72 hours rate factor was nested within the recycling agent factor. after fabrication, respectively, at five, 10, 15, and 20 MH Moreover, the cement content factor was nested within the blows.
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From page 60... ...
The curing ratio, defined as the ratio of the DPI at 2 hours Parameter DF f-Value p-Value Slab density 1 69.58 0.000 divided by the DPI at 72 hours, was used to evaluate the Recycling process 1 1.06 0.305 discrimination potential of DCP testing between curing times. Recycling agent type 1 14.47 0.000 Figure 3.43 shows the curing ratio of all evaluated mixtures.
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From page 61... ...
DPI, mm/blow Curing Time Mean Minimum Quartile 1 Quartile 3 Maximum Range Interquartile Range 2 hours 4.9 2.1 3.9 5.4 7.9 5.8 1.5 72 hours 2.7 1.0 1.9 3.4 4.8 3.8 1.4 Table 3.28. Descriptive statistics for DPI with respect to recycling agent and active filler type. DPI, mm/blow Material Interquartile Combination Mean Minimum Quartile 1 Quartile 3 Maximum Range Range Emulsion, cement 3.1 1.7 1.9 4.6 4.8 3.1 2.7 Emulsion, no 4.9 2.5 3.7 7.0 7.9 5.4 3.3 cement Foam, cement 3.1 1.0 2.0 4.2 5.6 4.6 2.2 Foam, no cement 4.3 2.7 3.5 5.1 6.0 3.3 1.6 2-hour 72-hour 50 Emulsion, Emulsion, Foam, Foam, Cement No Cement Cement No Cement 40 Coefficient of Variation, % 30 20 10 0 1 2 3 4 5-1 5-2 6 7 8 9 10 11 12 13 14 15 16 17-1 17-2 18 Mixture ID Figure 3.42. Coefficient of variation for DPI for mixtures with replicates.
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From page 62... ...
It is evident from Figures 3.44 and 3.45 that the LPST measurements were affected by curing and the presence of Parameter DF f-Value p-Value Slab density 1 2.49 0.122 cement. A curious trend was also observed for certain mix Recycling process 1 1.66 0.205 tures in that the number of blows or torque value was seen to Recycling agent type 1 9.10 0.004 decrease from the 1- to the 3-hour test time and then increase at Curing time 1 58.38 0.000 Recycling agent content 4 4.33 0.005 the 6- and 24-hour test times.
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From page 63... ...
of Process State Content, Density, ID Agent Filler Content, Replicates % pcf % 1 IN 2.5 1.0 119.1 2 CCPR 2 VA 2.5 1.0 127.6 0 Cement 3 TX 4.5 1.1 131.5 2 FDR 4 CA 2.5 1.0 127.8 1 5 Emulsified asphalt NY 3.0 0.0 122.0 2 CCPR 6 VA 2.5 0.0 127.6 3 No 7 CIR ON 1.2 0.0 121.4 2 cement 8 IN 2.5 0.0 119.1 2 FDR 9 CA 2.5 0.0 127.8 2 10 CCPR VA 2.5 1.0 127.6 3 11 CA 2.0 1.0 117.4 2 CIR 12 Cement MA 2.5 1.0 121.0 2 13 TX 2.4 1.5 125.6 2 FDR 14 Foamed asphalt CA 2.5 1.0 127.8 3 15 CCPR VA 2.5 0.0 127.6 0 16 No MI 2.2 0.0 129.8 2 CIR 17 cement WI 2.0 0.0 121.3 2 18 FDR CA 2.5 0.0 127.8 0 1-hour 3-hour 6-hour 24-hour 100 Emulsion, Emulsion, No Foam, No Cement Foam, Cement 80 Cement Cement Number of Blows 60 40 20 0 0 2 4 6 8 10 12 14 16 18 Mixture ID Figure 3.44. Number of blows to drive shear fixture into laboratory produced slabs. 1-hour 3-hour 6-hour 24-hour 300 Emulsion, Emulsion, Foam, Foam, No 250 Cement No Cement Cement Cement 200 Torque, ft-lbs 150 100 50 0 0 2 4 6 8 10 12 14 16 18 Mixture ID Figure 3.45. Torque values for field long-pin shear test.
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From page 64... ...
Mean, Minimum, Quartile Quartile Maximum, Range, Interquartile Curing Time ft-lbs ft-lbs 1, ft-lbs 3, ft-lbs ft-lbs ft-lbs Range, ft-lbs 1 hour 127.5 78.0 105.7 150.1 224.3 146.3 44.4 3 hours 128.6 68.7 110.5 149.8 212.7 144.0 39.3 6 hours 138.7 66.8 113.1 166.4 222.2 155.3 53.3 24 hours 147.5 76.8 114.4 179.3 217.3 140.6 64.8 Table 3.34. Descriptive statistics of torque values by recycling agent and active filler type. Material Mean, Minimum, Quartile Quartile Maximum, Range, Interquartile Combination ft-lbs ft-lbs 1, ft-lbs 3, ft-lbs ft-lbs ft-lbs Range, ft-lbs Emulsion, cement 164.3 110.8 137.8 191.9 222.2 111.3 54.1 Emulsion, no cement 111.6 66.8 79.7 133.4 168.0 101.2 53.7 Foam, cement 151.7 94.7 116.1 182.6 224.3 129.7 66.5 Foam, no cement 131.2 99.8 115.4 146.2 179.3 79.5 30.8
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From page 65... ...
as a function of curing These mixtures were manufactured using 12 sources of time, recycling agent rate with different recycling agent types, recycled materials. For some mixtures, two slab replicates 1-hour 3-hour 6-hour 24-hour 40 Emulsion, Emulsion, No Foam, Foam, No Cement Cement Cement Cement 30 COV for Torque, % 20 10 0 0 2 4 6 8 10 12 14 16 18 Mixture ID Figure 3.47. Variability of torque value in terms of coefficient of variation.
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From page 66... ...
Source DF f-Value p-Value Source DF f-Value p-Value Slab density 1 32.89 0.000 Slab density 1 36.75 0.000 Recycling process 1 22.17 0.000 Recycling process 1 10.56 0.002 Recycling agent type 1 2.3 0.132 Recycling agent type 1 17.64 0.000 Curing time 3 20.38 0.000 Curing time 3 6.44 0.001 Recycling agent content 6 10.38 0.000 Recycling agent content 6 5.57 0.000 Note: DF = degrees of freedom; bold/highlight = p-value Note: DF = degrees of freedom; bold/highlight = p-value shows the source to be significant. shows the source to be significant.
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From page 67... ...
Table 3.38 shows the descriptive statistics for SPRT for Mixture 13. There did not appear to be a clear trend with parameters using all collected data irrespective of curing respect to material combination, in part because of the low time, recycling agent type, and cement content.
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From page 68... ...
for full and half binder specimens with respect to recycling agent type and cement content. N1, Blows Material Interquartile Combination Mean Minimum Quartile 1 Quartile 3 Maximum Range Range Emulsion, cement 8.6 3.5 7.0 9.0 21.0 17.5 2.0 Emulsion, no cement 5.0 3.0 4.0 6.0 8.0 5.0 2.0 Foam, cement 7.7 4.0 5.0 9.0 16.0 12.0 4.0 Foam, no cement 5.4 3.5 5.0 6.0 9.0 5.5 1.0 1-hour 3-hour 6-hour 24-hour 120% Emulsion, Emulsion, Foam, Foam, COV for Number of Blows (N1)
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From page 69... ...
Table 3.42 contents, respectively. As with the number of blows, the shows the descriptive statistics for N2 with respect to recycling torque values showed a greater magnitude and spread for agent and presence of cement.
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From page 70... ...
. 1-hour 3-hour 6-hour 24-hour 120 Emulsion, Emulsion, No Foam, No Foam, Cement 100 Cement Cement Cement 80 Torque, ft-lbs 60 40 20 0 0 2 4 6 8 10 12 14 16 18 Mixture ID Figure 3.54. Torque value using raveling fixture (full binder content)
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From page 71... ...
Table 3.43. Descriptive statistics of torque value using raveling fixture for full and half binder specimens with respect to curing time. Raveling Torque, ft-lb Curing Time Mean Minimum Quartile 1 Quartile 3 Maximum Range Interquartile Range 1 hour 29.0 15.0 21.0 34.7 59.3 44.3 13.7 3 hours 31.5 11.6 21.2 41.8 48.9 37.3 20.6 6 hours 36.1 16.3 23.3 47.6 65.9 49.5 24.3 24 hours 46.0 23.4 31.1 51.8 107.4 84.0 20.7 Table 3.44. Descriptive statistics of torque value using raveling fixture for full and half binder specimens with respect to recycling agent and active filler type.
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From page 72... ...
Tables 3.48 and 3.49 show the Pearson correlation coef Parameter DF f-Value p-Value ficient and p-value for comparisons of the test slab density, Slab density 1 33.81 0.000 Recycling process 1 20.29 0.000 SSG stiffness, LWD modulus, and DPI values at curing periods Recycling agent type 1 10.37 0.002 of 2 and 72 hours, respectively. For those combinations that Curing time 3 12.68 0.000 were shown to have a strong correlation (|r| > 0.7, based on Note: DF = degrees of freedom; bolding indicates categories by Evans [1996]
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From page 73... ...
The coeffitests. The LPST torque value did not have a strong correlation cient of determination increased with respect to curing time, with the SPRT torque value.
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From page 74... ...
ksi LPST number of 0.5296 0.7690 0.7484 0.1404 −0.6922 blows LPST torque 0.7659 0.8595 0.5736 −0.7109 value, ft-lb SPRT number of 0.9475 0.3410 −0.9167 blows, N1 SPRT number of 0.4750 −0.8611 blows, N2 SPRT torque −0.6323 value, ft-lb * = Combination assessed as part of 2 and 72 hours comparison.
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From page 75... ...
modulus, ksi LPST number of 0.8734 0.8663 0.8315 −0.0319 blows LPST torque 0.9048 0.8644 −0.1108 value, ft-lb SPRT number of 0.9565 0.1154 DNT blows, N1 SPRT number of 0.0916 blows, N2 SPRT torque value, ft-lb DNT = did not test; * = combination assessed as part of 2 and 72 hours comparison.
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From page 76... ...
ksi LPST number of 0.8050 0.7906 0.8526 0.5575 blows LPST torque 0.8217 0.8090 0.5099 value, ft-lb SPRT number of 0.9746 0.6258 DNT blows, N1 SPRT number of 0.6688 blows, N2 SPRT torque value, ft-lb DNT = did not test; * = combination assessed as part of 2 and 72 hours comparison.
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From page 77... ...
ksi LPST number of 0.8479 0.9164 0.9405 0.2967 −0.6440 blows LPST torque 0.8555 0.9163 0.3874 −0.9292 value, ft-lb SPRT number of 0.9756 0.4126 −0.8860 blows, N1 SPRT number of 0.4371 −0.8733 blows, N2 SPRT −0.8755 torque value, ft-lb * = Combination assessed as part of 2 and 72 hours comparison.
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From page 78... ...
78 30 1-hour 3-hour 6-hour 24-hour 1-hour Trendline 3-hour Trendline 6-hour Trendline 24-hour Trendline y = 0.1647x + 1.4610 y = 0.1495x + 2.0120 y = 0.2064x + 0.7044 y = 0.1844x + 1.2269 R² = 0.5914 R² = 0.7505 R² = 0.625 R² = 0.8398 SPRT Number of Blows, N1 20 10 0 0 10 20 30 40 50 60 70 LPST Number of Blows Figure 3.57. Relationship between LPST number of blows and SPRT N1. 40 1-hour 3-hour 6-hour 24-hour 1-hour Trendline 3-hour Trendline 6-hour Trendline 24-hour Trendline y = 0.2688x + 3.6838 y = 0.2270x + 4.8617 y = 0.3236x + 2.3154 y = 0.3271x + 2.4185 R² = 0.5600 R² = 0.6913 R² = 0.727 R² = 0.8846 30 SPRT Number of Blows, N2 20 10 0 0 10 20 30 40 50 60 70 LPST Number of Blows Figure 3.58. Relationship between LPST number of blows and SPRT N2.
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From page 79... ...
14 1-hour 24-hour 1-hour Trendline 24-hour Trendline 12 y = -0.0910x + 9.1410 y = -0.0709x + 8.2700 R² = 0.3998 R² = 0.7665 10 DPI, mm/blow 8 6 4 2 0 0 20 40 60 80 100 120 SPRT Torque, ft-lb Figure 3.62. Relationship between SPRT torque value and DPI.
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From page 80... ...
First, the test had a high variability. Second, 30 1-hour 3-hour 6-hour 24-hour 1-hour Trendline 3-hour Trendline 6-hour Trendline 24-hour Trendline y = 0.1253x + 2.9528 y = 0.1863x + 2.6591 y = 0.343x + 0.5406 y = 0.3754x - 0.5557 25 R² = 0.2071 R² = 0.2878 R² = 0.5624 R² = 0.6892 SPRT Number of Blows N1 20 15 10 5 0 0 5 10 15 20 25 30 35 40 45 50 LWD Modulus, ksi Figure 3.64. Relationship between LWD modulus and SPRT N1.
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From page 81... ...
that were expected to influence the test results it is easier to assess when the fixture base plate is flush with were varied, and the resulting test value was analyzed with the surface of the recycled layer than to determine when the respect to the variation. Tables 3.55 and 3.56 show results Table 3.54. Assessment of tests for field testing recommendation.
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From page 82... ...
For each figure, error factor for the LPST number of blows, and the outer pin bars show plus/minus one standard deviation calculated diameter and torque angular rate were identified as signifi- from replicate test blocks. The numerical value at the base cant for the LPST torque value.
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From page 83... ...
torque value.
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From page 84... ...
Property Test Density Nuclear gauge density Stiffness Soil stiffness gauge Lightweight deflectometer Penetration resistance Dynamic cone penetrometer Shear resistance Long-pin shear test (number of blows and torque value) Raveling resistance Short-pin raveling test (number of blows [N2]
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From page 85... ...
3.5.1.1a Soil Stiffness Gauge Figure 3.68 shows the results of field testing using the SSG 3.5.1.2 Lightweight Deflectometer for FDR and CCPR mixtures, and Figure 3.69 shows them for CIR mixtures. Figure 3.68 shows that the SSG stiffness Figure 3.70 shows the LWD modulus field testing results of two of the three FDR mixtures and both CCPR mixtures for FDR and CCPR mixtures, and Figure 3.71 shows them was similar.
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From page 86... ...
in the shoulder areas. The research team Figure 3.72 shows the results of DCP field testing for FDR intentionally tested in these two locations to give a wider and CCPR mixtures, and Figure 3.73 shows them for CIR 45 40 35 LWD Modulus, ksi 30 25 20 15 10 5 1 1 3 1 2 1 3 1 2 2 0 1 hour 1.5 hours 1 hour 2 hours 1 hour 1 hour 1 hour 1 hour 1 hour 1 hour NY 23A NY 23A MN Cell CA SR 22 NY 30 NY 28 MN Cell IN SR 1- IN SR 1- CA SR 3 4 GS PS 178 CIR F-N CIR F-N CIR F-C CIR F-C CIR E-N CIR E-N CIR E-N CIR E-N CIR E-N CIR E-C Curing Time; Project; Recycling Process, Agent, and Active Filler Notes: F-N = foam, no cement; F-C = foam plus cement; E-C = emulsion plus cement; E-N = emulsion, no cement.
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From page 87... ...
12 10 8 DPI, mm/blow 6 4 2 1 1 3 1 2 1 3 1 2 2 0 1 hour 1.5 hours 1 hour 2 hours 1 hour 1 hour 1 hour 1 hour 1 hour 1 hour NY 23A NY 23A MN Cell CA SR 22 NY 30 NY 28 MN Cell IN SR 1- IN SR 1- CA SR 3 4 GS PS 178 CIR F-N CIR F-N CIR F-C CIR F-C CIR E-N CIR E-N CIR E-N CIR E-N CIR E-N CIR E-C Curing Time; Project; Recycling Process, Agent, and Active Filler Notes: F-N = foam, no cement; F-C = foam plus cement; E-N = emulsion, no cement; E-C = emulsion plus cement. Figure 3.73. DCP field testing results, CIR mixtures.
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From page 88... ...
Figure 3.73 also shows the influence of two other material properties. The NY 23A field project 3.5.3.2 Torque Value from New York showed that the DCP penetration index was Figure 3.76 shows the LPST torque value results for FDR sensitive to changes in curing time, where the penetration and CCPR mixtures, and Figure 3.77 shows them for CIR index decreased with respect to curing time, as expected.
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From page 89... ...
180 160 140 LPST Torque, ft-lb 120 100 80 60 40 20 2 2 3 3 5 3 0 1 hour 1 hour 3 hours 3 hours 1 hour 1 hour SC 123 NM US 491 MN Cell 1-HD MN Cell 1-LD MN Cell 7 MN Cell 5 FDR F-C FDR F-C FDR E-C FDR E-C CCPR F-C CCPR E-N Curing Time; Project; Recycling Process, Agent, and Active Filler Notes: F-C = foam plus cement; E-C = emulsion plus cement; E-N = emulsion, no cement. Figure 3.76. Long-pin shear test torque value field testing results, FDR and CCPR mixtures.
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From page 90... ...
20 18 16 SPRT Number of Blows 14 12 10 8 6 4 2 2 2 3 3 5 3 0 1 hour 1 hour 3 hours 3 hours 1 hour 1 hour SC 123 NM US 491 MN Cell 1-HD MN Cell 1-LD MN Cell 7 MN Cell 5 FDR F-C FDR F-C FDR E-C FDR E-C CCPR F-C CCPR E-N Curing Time; Project; Recycling Process, Agent, and Active Filler Notes: F-C = foam plus cement; E-C = emulsion plus cement; E-N = emulsion, no cement. Figure 3.78. Short-pin raveling test number of blows field testing results, FDR and CCPR mixtures.
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From page 91... ...
Figure 3.80. Short-pin raveling test torque value field testing results, FDR and CCPR mixtures.
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From page 92... ...
The analysis showed that the following combinations had a strong, statistically significant correlation: Prior to conducting any of the tests in the field, suitable and uniform sites were selected based on visual observation • SSG stiffness with LWD modulus; of the recycling process and the completed recycled layer. • LPST number of blows with LPST torque value, SPRT As an example, cement as an active filler was observed to torque value, and DPI; be applied non-uniformly across the width of the lane on
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From page 93... ...
(a) SSG LWD LPST LPST SPRT SPRT DPI, stiffness, Modulus, Number of Torque, Number of Torque, mm/blow MN/m ksi Blows ft-lb Blows ft-lb Density, 0.0338 0.0831 0.5562 0.4963 0.5639 0.5389 −0.3611 lb/ft3 SSG stiffness, 0.9106 0.6237 0.3298 0.5488 0.5134 −0.2496 MN/m LWD modulus, 0.3686 0.0759 0.3189 0.2505 −0.0604 ksi LPST number of 0.8839 −0.4291 0.8654 −0.7363 blows LPST torque, ft- 0.8863 0.8756 −0.7033 lb SPRT number of 0.9281 −0.7921 blows SPRT torque, ft- −0.6648 lb (b)
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From page 94... ...
50 40 SPRT Torque, ft-lb 30 20 10 y = 0.7085x + 8.7120 R² = 0.7490 0 0 10 20 30 40 50 LPST Number of Blows Figure 3.84. Relationship between long-pin shear test number of blows and short-pin raveling test torque value.
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From page 95... ...
50 40 SPRT Torque, ft-lb 30 20 10 y = 0.2548x + 5.4441 R² = 0.7667 0 0 20 40 60 80 100 120 140 160 180 LPST Torque, ft-lb Figure 3.87. Relationship between long-pin shear test torque value and short-pin raveling test torque value.
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From page 96... ...
14 12 10 DPI, mm/blow 8 6 4 2 y = -0.4173x + 10.0762 R² = 0.6274 0 0 5 10 15 20 SPRT Number of Blows Figure 3.90. Relationship between short-pin raveling test number of blows and DPI.
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From page 97... ...
For both tests, the operator listened for a During initial stages of the field testing, there was concern change in the sound while driving the fixture to note when that the recycled material might be susceptible to raveling the base plate was touching the surface of the recycled layer. after completion of the field tests given that most of the The rate at which the torque was applied was kept constant projects were opened to traffic soon after the tests were comfrom location to location by drawing a line (using a lumber pleted.
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From page 98... ...
Positive or for penetration resistance testing using the DCP, number of negative h-values show that an average property measure of blows and torque value for the LPST, and number of blows and a laboratory is larger or smaller than the average property torque value for the SPRT. Following a presentation of the measures of other laboratories.
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From page 99... ...
tion and COV for DPI with respect to test cells are presented Tables 3.61 and 3.62 show the analysis of data consistency in Table 3.63, as calculated in accordance with ASTM C802. for DPI in terms of the calculated k-values and h-values, To determine the form of the precision statements, the respectively.
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From page 100... ...
1.0 Linear (Multi-Laboratory) R² = 0.67 0.8 0.6 0.4 R² = 0.27 0.2 0.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 DPI, mm/blow Figure 3.95. Relationship between average DPI measurements and standard deviation.
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From page 101... ...
Note: These precision statements are based on an ILS Similarly, Tables 3.68 and 3.69 show the calculated k-values that involved three laboratories, four materials, and three and h-values for the LPST torque values for each test cell, replicate tests per operator, with DPIs ranging from 3.8 to respectively. All the h- values and k-values were within the 8.7 mm/blow.
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From page 102... ...
Table 3.69. h-values for between-laboratory data consistency for LPST torque values. Torque Value, ft-lb Laboratory Cell 1 Cell 1 Cell 3 Cell 4 Cell 5 Cell 7 FDR E-C FDR E-C LD CIR F-C CIR E-N CCPR E-N CCPR F-C Lab 1 −0.38 −0.48 −0.01 0.05 −0.64 −0.13 Lab 2 −0.75 −0.67 1.00 −1.02 −0.52 −0.93 Lab 3 1.14 1.15 −0.99 0.97 1.15 1.06 Note: Critical h-value equals ± 1.15.
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From page 103... ...
Table 3.70. LPST number of blows average, standard deviation, and coefficient of variation. Number of Blows Standard Deviation Coefficient of Variation, % Test Cell/Material Average Single Multi- Single Multi Operator Laboratory Operator Laboratory Cell 1 FDR E-C LD 13.1 2.1 3.4 15.9 25.7 Cell 1 FDR E-C 18.2 1.9 2.6 10.2 14.3 Cell 4 CIR E-N 18.8 0.5 0.9 2.5 4.9 Cell 5 CCPR E-N 23.0 1.5 2.4 6.5 10.3 Cell 7 CCPR F-C 30.8 1.2 3.1 3.9 10.0 Cell 3 CIR F-C 42.6 2.6 3.5 6.2 8.2
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From page 104... ...
Linear (Multi-Laboratory) Standard Deviation 4 R² = 0.16 3 2 R² = 0.16 1 0 0 10 20 30 40 50 LPST Number of Blows Figure 3.99. Relationship between average LPST number of blows and standard deviation.
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From page 105... ...
Therefore, the pooled number of blows measurements. single-operator and multi-laboratory standard deviations Similarly, the relationship between the average LPST from Table 3.71 were used to develop the precision statements torque value and corresponding standard deviation for for LPST torque values.
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From page 106... ...
deviation was 8.1 ft-lbf. Therefore, the results of two Similarly, Tables 3.76 and 3.77 show the calculated k-values properly conducted tests by the same operator on the and h-values for the SPRT torque values for each test cell, same material are not expected to differ by more than respectively.
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From page 107... ...
The figures show that the COV is single-operator and multi-laboratory COV stayed relatively the appropriate basis for developing the precision statements constant with changes in the LPST torque value. Thus, the use for SPRT number of blows as the COV overall tended to be of a constant COV is appropriate for developing the precision relatively more independent than the standard deviation for statements for SPRT torque values.
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From page 108... ...
Table 3.78. SPRT number of blows average, standard deviation, and coefficient of variation. Number of Blows Standard Deviation Coefficient of Variation, % Test Cell/Material Average Single Multi- Single Multi Operator Laboratory Operator Laboratory Cell 1 FDR E-C LD 5.6 0.3 1.4 6.0 25.5 Cell 4 CIR E-N 7.6 0.5 0.5 6.2 7.2 Cell 1 FDR E-C 7.6 0.9 3.3 12.5 43.4 Cell 5 CCPR E-N 8.4 0.5 0.8 5.6 9.4 Cell 7 CCPR F-C 10.9 1.0 1.8 9.2 16.3 Cell 3 CIR F-C 15.7 1.4 1.4 8.8 9.1
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From page 109... ...
Linear (Multi-Laboratory) Standard Deviation 2 R² = 0.00 1 R² = 0.77 0 4 6 8 10 12 14 16 18 SPRT Torque, ft-lb Figure 3.105. Relationship between average SPRT number of blows and standard deviation.
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From page 110... ...
0 10 20 30 40 50 SPRT Torque, ft-lb Figure 3.107. Relationship between average SPRT torque value and standard deviation. 27 Single-Operator 24 Multi-Laboratory 21 Linear (Single-Operator)
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From page 111... ...
Despite the good Mean correlation shown during the Phase III field testing between the number of blows and torque value for each fixture, these Figure 3.109. Example normal distribution two components of each test are recommended since the with threshold value at a left-tail area of 5%.
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From page 112... ...
No standard binder is added. deviation was calculated for the SPRT torque value during Table 3.81. Threshold values and Phase III results from two sites.
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From page 113... ...
Deviations) Short-pin Number of blows 7.1 3.7 0.8 5.0 2.4 0.8 3.7 raveling test Torque, ft-lb 20.2 12.6 2.5 15.6 15.4 2.5 19.5 Long-pin Number of blows 19.3 7.3 2.1 9.8 6.2 2.1 9.7 shear test Torque, ft-lb 62.9 42.2 8.2 51.9 26.1 8.2 39.6 the field trial since the test value was near the lower limit of there were more observations (50)
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Key Terms
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information on Chapter Skim is available.