Optimizing the value of soil compaction testing quality assurance and control using stochastic life cycle cost, comparative and statistical analysis

Abstract

The nuclear density gauge has been the standard soil compaction acceptance method for the Missouri Department of Transportation (MoDOT) for several decades. However, the cost of licensing, security, transport protocol and training imposed by the federal government have caused MoDot to question whether it remains a cost effective testing technology.. Nuclear density testing's rapidity and accuracy has been crucial in enabling MoDOT inspectors to keep contractor grading processes on schedule. But, in the last two years MoDOT's Quality Management program has shifted the bulk of testing requirements to the contractor, reducing the need for MoDOT inspection on grading projects. As a result,, MoDOT is investigating compaction testing alternatives to the nuclear density gauge which can provide the necessary results at a lower life cycle cost. The investigation comprised a comprehensive review of previous research into compaction testing alternative as well as key findings and gaps in research. This led to the purchase of XX pieces of alternative test equipment which were employed simultaneously alongside the nuclear density gauge on four large structural fill projects. The field testing yielded a set of comparable test results taken at the same time, in roughly the same location, and under the same environmental conditions, and arguably making this research the most comprehensive study of compaction testing technology on record. The dissertation discusses MoDOT's Quality Management program's development and links to its origin in Design-Build project best practices, which provided the motivation to seek alternatives to the nuclear density gauge. Life Cycle Cost Analysis and Cost Index theory was utilized in comparing the compaction testing alternatives and presenting present cost per compaction test for the Department. For MoDOT project sites, linear and multiple regression DOT Respondents with Design-build Experience DOT Respondents without Design-build Experience State Position State Position State Position Alaska Construction engineer Nevada Geotechnical engineer Alabama Construction engineer Arkansas Design project manager New Jersey Construction engineer Connecticut Geotechnical engineer California Design project manager New Mexico Geotechnical engineer Illinois Design project manager Colorado Design-build project manager New Hampshire Design project manager Iowa Design project manager Florida Construction engineer North Carolina Geotechnical engineer Kansas Construction engineer Idaho Construction engineer North Dakota Design project manager Nebraska Design project manager Indiana Geotechnical engineer Ohio Design project manager New York Design project manager Kentucky Construction engineer Oregon Geotechnical engineer Oklahoma Construction engineer Louisiana Geotechnical engineer South Carolina Design project manager Wyoming Design project manager Maine Geotechnical engineer South Dakota Geotechnical engineer Maryland Materials engineer Tennessee Construction engineer Massachusetts Design-build project manager T...

Contractor-furnished compaction testing: searching for correlations between potential alternatives to the nuclear density gauge in Missouri highway projects

“…This role change, combined with a decreased number of major grading projects leads to the need to conduct considerably fewer tests, MoDOT therefore found it prudent to re-evaluate its use of the NDG in light of the large number of administrative requirements for training, certification, calibration, and storage. An internal study completed in to be approximately $632,000 (McLain 2015). …”