Browsing by Author "Meehan, Christopher L.(orcid.org/0000-0002-9721-6275)"

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    A Comparison of Simultaneously Recorded Machine Drive Power and Compactometer Measurements
    (ASTM International, 2011) Meehan, Christopher L.; Tehrani, Faraz S.; Meehan, C. L., Tehrani, Faraz S.; Meehan, Christopher L.(orcid.org/0000-0002-9721-6275)
    Continuous compaction control (CCC) systems are data acquisition systems installed on compaction equipment that continuously collect real-time information about the operation and performance of the compactor. An experimental research study was conducted to examine the type of data that is recorded by CCC equipment during road sub-base compaction of “select fill” granular materials using a smooth-drum vibratory roller. A prototype roller was utilized that allowed for simultaneous real-time machine drive power and compactometer measurements, which permitted independent and simultaneous evaluation of the degree of compaction of the soil. The behavior of the recorded machine drive power and compactometer values for different lifts and with increasing compactive effort for a single lift is presented and discussed. The statistical nature of the recorded CCC data sets is explored in detail, with a focus on distribution fitting assessment techniques that are applicable for CCC data. Comparisons are also made between the simultaneously recorded machine drive power and compactometer measurements. The results and associated discussion that are presented are useful for understanding the variable nature of CCC data sets, and the observations that are made have practical implications for the creation of CCC construction specifications that are to be used to control the compaction process.
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    Measuring Drained Residual Strengths in the Bromhead Ring Shear
    (ASTM International, 2007) Meehan, Christopher L.; Brandon, Thomas L.; Duncan, J. M. (James Michael); Meehan, C. L., Brandon, T. L., Duncan, J. M.; Meehan, Christopher L.(orcid.org/0000-0002-9721-6275)
    A series of Bromhead ring shear tests were conducted to measure the drained residual strength of Rancho Solano Fat Clay. Tests conducted using different test procedures demonstrate the significant effect that wall friction can have in the Bromhead ring shear device. This problem was addressed by beveling the top loading platen, which led to measurements of drained residual strength that were 21–23 % lower than those measured with the unmodified platen. Using the modified platen, similar test results can be achieved independent of the details of the test procedure that is followed, giving greater confidence in the measured residual shear strength.