Abstract: The present invention provides an improved thin layer nuclear density gauge comprising a gauge housing having a vertical cavity therethrough and a base, a first radiation detector located at a first position within said housing and adjacent to said base of said housing, a second radiation detector located at a second position within said housing and adjacent to said base of said housing, a vertically moveable source rod extending into said cavity of said gauge housing, a radiation source operatively positioned within a distal end of said source rod, at least one bearing operatively positioned to guide said source rod within said cavity, and means for vertically extending and retracting said source rod to a plurality of predetermined source rod positions so as to change the spatial relationship between said radiation source and said first and second radiation detectors. The source rod has a maximum radial movement of less than about 0.003 inch at each predetermined position.

Abstract: The present invention provides an improved thin layer nuclear density gauge comprising a gauge housing having a vertical cavity therethrough and a base, a first radiation detector located at a first position within said housing and adjacent to said base of said housing, a second radiation detector located at a second position within said housing and adjacent to said base of said housing, a vertically moveable source rod extending into said cavity of said gauge housing, a radiation source operatively positioned within a distal end of said source rod, at least one bearing operatively positioned to guide said source rod within said cavity, and means for vertically extending and retracting said source rod to a plurality of predetermined source rod positions so as to change the spatial relationship between said radiation source and said first and second radiation detectors. The source rod has a maximum radial movement of less than about 0.003 inch at each predetermined position.

Abstract: The present invention provides an improved thin layer nuclear density gauge comprising a gauge housing having a vertical cavity therethrough and a base, a first radiation detector located at a first position within said housing and adjacent to said base of said housing, a second radiation detector located at a second position within said housing and adjacent to said base of said housing, a vertically moveable source rod extending into said cavity of said gauge housing, a radiation source operatively positioned within a distal end of said source rod, at least one bearing operatively positioned to guide said source rod within said cavity, and means for vertically extending and retracting said source rod to a plurality of predetermined source rod positions so as to change the spatial relationship between said radiation source and said first and second radiation detectors. The source rod has a maximum radial movement of less than about 0.003 inch at each predetermined position.

Abstract: An apparatus for pyrolysis of a sample of a composite material containing a combustible binder includes a combustion chamber configured to receive a sample of the composite material and having an outlet. A heater is associated with the combustion chamber for heating the chamber to a temperature sufficient for pyrolysis of the binder. A blower is in fluid communication with the combustion chamber for creating an airflow through the outlet to remove airborne pyrolysis products from the combustion chamber. An adjustable airflow regulator is operable to adjustably control the airflow to provide a desired minimum residence time within the combustion chamber sufficient for complete pyrolysis of the airborne pyrolysis byproducts.

Abstract: An apparatus and method for testing rutting susceptibility of test specimens. The apparatus includes a specimen holder having cavities for receiving one or more test specimens having an exposed surface for testing. A load bearing surface is positioned above the specimens to prevent friction from effecting the rutting analysis. A load device including at least one loading wheel is positioned adjacent the specimen holder wherein the loading wheels matingly engage the load bearing device. A motive sources provides relative rotational movement between the specimen holder and the loading wheels whereby a load is repeatedly applied to the test specimens under a constant velocity. The method includes testing rutting susceptibility of test specimens by providing a rotational load thereupon whereby the load reflects a linear or constant load across the predetermined path of travel of the loading wheels over the exposed surface of the test specimens.

Abstract: An apparatus for compacting a material sample, such as paving material, including a cylindrical compaction mold and a mold support arranged to support one end of the mold. The mold support includes a turntable mounted for rotation about a rotational axis and a pair of mold-engaging members, such as rollers, extending from the turntable to engage the mold along its periphery and impart a gyratory motion to the mold as the turntable rotates. A mold retainer is also provided that includes a plurality of mold restraints spaced apart from one another about a central axis and arranged to engage the mold about the mold periphery at the end of the mold opposite the mold support. One of the mold restraints is attached to a movable latch that moves the mold restraint between an open position and a closed position. The open position locates the mold restraint out of engagement with the mold to allow the mold to slide into position inside the compactor apparatus.

Abstract: An apparatus and method for compacting a material sample, such as soil or paving material, including a mold for receiving the material sample and a ram mounted for movement into a first open end of the mold to provide an axial compressire force thereto. The compacting apparatus also includes a base for supporting a second end of the mold. In operation, the mold is gyrated simultaneously with the application of the axial compressire force by the ram. Gyration is provided by tilting the mold from an initial neutral position in which the center longitudinal axis of the mold is collinear with the axis of compression to a tilted operative position in which the central longitudinal axis of the mold is angularly offset from the axis of compression. The base is thereinafter rotated relative to the mold so as to revolve the center of the second end of the mold about the axis of compression, thus, gyrating the axially compressed material sample.