With a goal of eliminating the costly and logistically complex paperwork associated with nuclear density testing, this project developed and automated a small diameter pressuremeter, called the SSMiniPMT, for use during compaction quality control. Soil strengths and stiffnesses vary for the same density materials; therefore, engineers are much better off knowing strength and stiffness rather than density, an index property. The existing database of SSMini Pressuremeter (PMT) and nuclear density correlations was improved by more than doubling the number of tests. Testing was completed in both clays and sands. A Standard Test Method for Testing with Either Analog or Digitally Automated Small Diameter Pressuremeter Equipment at Shallow Depths was developed. The SSMini probe designs were improved allowing easier assembly and handling. The testing control unit was completely redesigned, producing fully automated highly repeatable Strength and Stiffness results in less than 1 minute with the click of a mouse. This last development is why the Small Diameter PMT is now called the SSMini PMT. SSMini PMT tests are conducted by first driving a ¾-inch diameter pin through a template to the desired test depth, then placing the desired 6-, 8-, 10-, or 12-inch-long probe into the hole, pressing the computer screen button and watching as the motor-driven equipment produces a stress-strain curve with elastic modulus and strength (i.e. limit pressure). The recorded stress-strain data is then used to determine E and pL and can even be used to predict a resilient modulus. Several approaches were developed to allow engineers to use the SSMini moduli and strengths for compaction quality control. One involved combining Proctor moisture-density data, degree of saturation, and SSMini E₀ data on a plot that can be used in the field to determine compaction acceptance immediately.

The Final Report is available here.