Embankment Quality and Assessment of Moisture Control Implementation

dc.contributor.author White, David
dc.contributor.author White, David
dc.contributor.author Li, Shengting
dc.contributor.author Vennapusa, Pavana
dc.contributor.department Institute for Transportation
dc.date 2018-02-17T15:52:53.000
dc.date.accessioned 2020-06-30T04:51:39Z
dc.date.available 2020-06-30T04:51:39Z
dc.date.embargo 2016-04-06
dc.date.issued 2016-02-01
dc.description.abstract <p>A specification for contractor moisture quality control (QC) in roadway embankment construction has been in use for approximately 10 years in Iowa on about 190 projects. The use of this QC specification and the development of the soils certification program for the Iowa Department of Transportation (DOT) originated from Iowa Highway Research Board (IHRB) embankment quality research projects. Since this research, the Iowa DOT has applied compaction with moisture control on most embankment work under pavements. This study set out to independently evaluate the actual quality of compaction using the current specifications. Results show that Proctor tests conducted by Iowa State University (ISU) using representative material obtained from each test section where field testing was conducted had optimum moisture contents and maximum dry densities that are different from what was selected by the Iowa DOT for QC/quality assurance (QA) testing. Comparisons between the measured and selected values showed a standard error of 2.9 lb/ft3 for maximum dry density and 2.1% for optimum moisture content. The difference in optimum moisture content was as high as 4% and the difference in maximum dry density was as high as 6.5 lb/ft3 . The difference at most test locations, however, were within the allowable variation suggested in AASHTO T 99 for test results between different laboratories. The ISU testing results showed higher rates of data outside of the target limits specified based on the available contractor QC data for cohesive materials. Also, during construction observations, wet fill materials were often observed. Several test points indicated that materials were placed and accepted at wet of the target moisture contents. The statistical analysis results indicate that the results obtained from this study showed improvements over results from previous embankment quality research projects (TR-401 Phases I through III and TR-492) in terms of the percentage of data that fell within the specification limits. Although there was evidence of improvement, QC/QA results are not consistently meeting the target limits/values. Recommendations are provided in this report for Iowa DOT consideration with three proposed options for improvements to the current specifications. Option 1 provides enhancements to current specifications in terms of material-dependent control limits, training, sampling, and process control. Option 2 addresses development of alternative specifications that incorporate dynamic cone penetrometer or light weight deflectometer testing into QC/QA. Option 3 addresses incorporating calibrated intelligent compaction measurements into QC/QA.</p>
dc.format.mimetype PDF
dc.identifier archive/lib.dr.iastate.edu/intrans_techtransfer/104/
dc.identifier.articleid 1103
dc.identifier.contextkey 8436700
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath intrans_techtransfer/104
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/44949
dc.language.iso English
dc.source.bitstream archive/lib.dr.iastate.edu/intrans_techtransfer/104/embankment_quality_and_assess_moisture_ctrl_t2.pdf|||Fri Jan 14 18:20:11 UTC 2022
dc.subject.disciplines Civil Engineering
dc.subject.keywords Best practices
dc.subject.keywords Compaction
dc.subject.keywords Embankments
dc.subject.keywords Grading (Earthwork)
dc.subject.keywords Moisture content
dc.subject.keywords Quality assurance
dc.subject.keywords Quality control
dc.subject.keywords Test procedures
dc.subject.keywords compaction moisture control; embankment construction; embankment soils; field testing methods; grading projects; Iowa soils; moisture control criteria; moisture/density control; quality assurance; quality control; specifications
dc.title Embankment Quality and Assessment of Moisture Control Implementation
dc.type article
dc.type.genre report
dspace.entity.type Publication
relation.isAuthorOfPublication cef57bd6-542c-4c8b-9d18-b327bf3befc2
relation.isOrgUnitOfPublication 0cffd73a-b46d-4816-85f3-0f6ab7d2beb8
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