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

The Missouri Department of Transportation’s (MoDOT) past and present Quality Control and Quality Assurance programs for construction are examined. MoDOT’s present Quality Management program along with a small number of grading projects has lowered the number of Quality Assurance (QA) soil compaction tests completed in the past two years. The Department would like to rid itself of using the Nuclear Density Gauges because of burdensome Federal regulations, required training, security and licensing fees. Linear and multiple regression analysis was performed to see if a correlation between nuclear density gauge dry densities values and Light Weight Deflectometer modulus values/ Clegg Hammer Clegg Impact Values exist. These relationships or lack thereof will determine the technology used by construction contractors to perform compaction quality control testing if MoDOT moves away from using nuclear density gauges for soil density verification.