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Asphalt Pavement Technology
Bituminous Mixtures Laboratory (BML)
Equipment Linear Kneading Compactor
Used to compact asphalt paving mixtures into slabs needed for various mixture testing devices. The mixture is placed in a mold and loaded through a series of vertically aligned steel plates that compress the asphalt mixture into a flat slab of predetermined thickness and density.
The Linear Kneading Compactor produces slabs that are used for testing asphalt mixtures for various properties. A mixture is placed in a steel mold in the compactor and a series of vertically aligned steel plates are positioned on top of it. A steel roller then transmits a rolling action force through the steel plates, one plate at a time. The mixture is kneaded and compressed into a flat slab of predetermined thickness and density. The trade name for this compactor is HasDek SLAB-PAC. It is manufactured by R/H Specialty & Machine, Terre Haute, Indiana. This compactor costs $66,000 and is shown in figure 1.
The Linear Kneading Compactor is called "linear" because of the lateral motion involved. The mold, mixture, and steel plates move back and forth on a sliding table under the roller. It is called "kneading" because only a fraction of the mixture is compacted at any given time. This kneading action allows the mixture to be compacted without excessively fracturing the aggregate.
The density of the mixture at the required air-void level and the dimensions of the slab are used to calculate the mass of mixture needed. Once the mixture is placed in the mold, 5 to 15 min are required to achieve the desired density. Two different mold sizes are available-a 260- by 320-mm mold that provides slabs used by the Hamburg Wheel-Tracking Device, and a 180- by 500-mm mold that provides slabs used by the French Pavement Rutting Tester. Other mold sizes can be easily accommodated. The slabs produced by this compactor can also be cored or sawed into beams. Beam specimens needed for the Georgia Loaded-Wheel Tester are provided by cutting the slab for the Hamburg Wheel-Tracking Device in half.