Intelligent Soil Compaction Systems (2010) / Chapter Skim
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This chapter presents six case studies performed to illustrate implementation of the recommended quality assurance (QA) specification options detailed in Chapter 7 (see Table 8.1)
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0 roll. For this case study, the specification options were evaluated using the contract γ d -TV.
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static proof roll test after pass 8. The Evaluation Section passed the static proof roll test despite very small areas with high clay content being identified for remediation, which involved scraping the clay material out with a motor grader.
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Figure 8.2. Roller MV maps of the Calibration Area and Evaluation Section, MV spot-test measurement correlations, and cumulative distribution of MV data after pass 8.
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table 8.2. option 1: Spot-test Measurements from weakest areas.
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8.1.4 acceptance Using Specification option 3a 8.1.4.1 Initial Calibration Option 3a requires calibration of roller MVs to spot-test measurements to determine an MV-TV. A Calibration Area was selected at the southern end of the Evaluation Section (Figure 8.1)
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retrospect this is an inappropriate Calibration Area for the Evaluation Section. Figure 8.5 shows a comparison of CMVγ d correlations from the Calibration Area and Evaluation Section, determined from the data presented in Figure 8.2.
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Area. Including the time needed to construct the Calibration Area, the correlations were developed in approximately three to four hours, although a time frame of one to two hours would be more consistent with production schedules.
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spot testing. The third area was not tested due to time constraints.
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8.2.3 acceptance Using Specification option 2b The repeatability of k s-CSM at the Florida work site was determined to be 5% based on the procedure in Section 7.5.3.1; therefore, the Option 2b %∆-TV was set equal to 10% for this case study. As with Case Study I, a %Area-TV = 80% was used.
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improve reliability, it may be desirable to implement Option 2a or 2b in conjunction with Option 1. This case study also illustrated the importance of assessing whether or not a positive correlation exists between the roller MV and the spot-test measurements used for QA.
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0 Figure 8.10. Roller MV (CMVD )
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Figure 8.11. Compaction growth curves for roller MV (CMVD )
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Figure 8.13. Simple regression relationships between roller MV (CMVD )
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Figure 8.14. CMVD map of the Evaluation Section and CBR profiles at select locations.
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MV-TV; therefore, the Evaluation Section does meet the German acceptance requirements. ISSMGE specifications are described in Section 2.3.2.
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Figure 8.16. Uniformity-based acceptance criterion for Evaluation Section using spatial and univariate statistics.
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Figure 8.17. Evaluation of the Evaluation Section using Specification Option 3a in comparison to German, ISSMGE, and Mn/DOT acceptance criteria.
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scribed above. As shown in Table 8.6, the target ∆µk s of 5% was achieved after pass 3.
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Figure 8.20. Kriged spatial maps of ks from pass 1 to pass 6 and corresponding percent increase in roller ks for each consecutive pass.
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nearest point data) are compared with calibration relationships in Figure 8.22.
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0 Figure 8.22. ks map of the Evaluation Section, CBR profiles at select locations, and comparison of production test measurements with the established QA criteria.
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8.4.6 Comparison to german, ISSmge, and mn/doT Specifications acceptance Criteria Acceptance criteria using the existing German, ISSMGE (2005)
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Figure 8.25. Acceptance using German, ISSMGE, and Mn/DOT specifications.
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Using the Mn/DOT specification, MV-TV = 25 is established from the calibration data. The Evaluation Section k s showed that only about 29% of the area is within 90% to 130% of MV-TV range.
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Figure 8.27. Roller MV maps of the Calibration Area and Evaluation Section, MV and spot-test measurement correlations and cumulative distribution of MV data.
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correlation did exist between the roller MV and γ d . However, this correlation was not acceptable (R2 = 0.21)
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finish hauling and placing a section. In typical production compaction practice, roller compactors are used throughout the hauling, placing, and grading operation.
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values were selected. Comparison of predicted M r and E vib for the selected data is presented in Figure 8.30(a)
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more stringent than current random selection spot testing. Reducing the QA-TV may be more appropriate.
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than ideal Rolling Patterns and creates hazardous conditions for personnel performing spot-test measurements. Performing correlation studies in a designated full-width Calibration Area requires a change in how the earthwork contractor places material.
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