Browsing by Subject "Test rolling"

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    Development of Improved Test Rolling Methods for Roadway
    (Minnesota Department of Transportation, 2008-02) Hambleton, J.; Drescher, Andrew
    Test rolling is a quality assurance test in which penetration of the wheels of a heavy vehicle into subgrade soils is used as a measure of the adequacy of compaction. Current criteria for acceptable test roller penetration are empirical. Two theoretical approaches for modeling test rolling are developed. One is analytic and the other is numerical, based on the finite element code ABAQUS. Both approaches relate wheel penetration to wheel geometry, wheel load, and soil strength parameters (friction angle and cohesion). Elastic soil properties are included in the numerical simulations but play a secondary role. The models accommodate both rigid and flexible wheels. Homogeneous and layered soil structures are considered. Scaled laboratory tests support the theoretical predictions, although full validation requires execution of extensive full scale field testing. The models developed can be used to enhance interpretation of test rolling data and assess the effects of test roller modifications.
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    Intelligent Compaction Implementation: Research Assessment
    (Minnesota Department of Transportation, 2008-07) Labuz, Joseph F.; Guzina, Bojan; Khazanovich, Lev
    The objective of this project was to provide a qualitative assessment of the Minnesota Department of Transportation’s Intelligent Compaction (IC) Specifications. IC is an attractive approach to evaluate the compaction quality because it involves continuous and instantaneous evaluation of the soil through machine-drive power or drum vibration monitoring. Four construction sites utilizing IC were visited: (1) TH 36 in North St. Paul, involving both granular and nongranular soils; (2) US 10 in Staples, with granular soil; (3) TH 60 in Bigelow, with nongranular soil; (4) US 10 in Detroit Lakes, involving both granular and nongranular soils. The report integrates comments from the four site visits and provides an interpretation on the use of IC at each site. As the technology now exists on the equipment used at these locations, IC provides only an index, which is specific to the conditions associated with a particular site. An interpretation of comments provided the basis for the following recommendations: • Use light weight deflectometers (LWD) for quality assurance of stiffness • Establish a procedure to determine the target LWD value • Eliminate calibration areas (control strips) • Simplify IC data evaluation and presentation • Calibrate the IC roller and related transducers • Support development of alternative IC methodologies • Simplify or eliminate moisture corrections