When pushed across a slab, the tool folds a strip of plastic tape and embeds it into fresh concrete. The top edge of the tape sits slightly below the surface of the slab. The joints are installed early in the construction sequence, while the concrete is highly workable immediately before or after the bullfloating operation. The tape remains in the slab to create an effective contraction joint.
The advantages of using the Traker are cost and speed. The Traker installs joints at 75% less cost than sawcut joints, and four times faster. The primary market for the Traker is residential slabs-on-ground, where contraction joints are hidden by floor coverings. Joints formed by the Traker appear as narrow joint-cracks in the slab. Contraction joints are required in residential slabs, following ACI Residential Code (ACI 332), and for this application the appearance of joints is inconsequential.
The embedded tape provides another advantage: it functions as a vapor retarder to reduce moisture emissions moving through contraction joints. The tape also prevents rainwater from moving down into the contraction joints, which keeps the sub-base soil dry.
The height of the insertion disc is adjustable to permit contraction joint depths to range from 1 to 2 inches. These joints reliably crack the slab because they are installed as early entry joints in fresh concrete. Typically, joint-cracks appear the day after concrete placement.
The tool itself operates in a straight forward manner. An insertion disc rotates by friction as the Traker is pushed or pulled. A roll of tape rests against the insertion disc, and tape is pulled off the roll and folded while being embedded in the concrete. The Traker can be used on slabs up to 60 ft. wide. For the first 30 ft., the Traker is pushed, and for the remaining 30 ft. it is pulled. The speed at which the Traker travels across the slab is equivalent to a person walking, about 3 to 4 ft./sec. At the beginning and end of each run, a tail of tape gets manually tucked into the concrete using the edge of a trowel.
Aaron Hilbert LLC