UFC 3-270-04
15 March 2001
the pipe are plugged, the plug must fit inside the pipe and be flush with the end of the pipe so that
there will be no protruding material to bond with the concrete and prevent free movement of the
dowel. When using smooth steel dowels, slots for the dowels are cut using diamond-blade saws.
Multiple blade saws may be used to speed operations. The slots should be cut so that the
dowels are allowed to rest horizontally and perpendicular to the crack or joint and at middepth of
the slab (Figure 10.1.). Light-weight chipping hammers are used to remove the concrete within
the slots. The slot is then cleaned by sandblasting or any method that will ensure removal of all
sawing residue, dirt, or oil that may prevent bonding of the patch material to the slot faces. Each
dowel is placed upon a support chair to allow the patch material to surround the dowel. One end
of the dowel is oiled and painted and an expansion cap placed on the end (Figure 10.1.). The
dowels must be provided with a filler board or styrofoam material at midlength to prevent intrusion
of the patch material into the joint or crack and to form the joint in the slot (Figure 10.2.).
10.4.2. Proprietary Shear Device. Proprietary shear devices such as the Double Vee Device and
the Plate Stud Connector have been used and are reported to be effective for load transfer
across joints and cracks. The placement of proprietary shear devices must be in accordance with
the manufacturer's recommendations. The following are general recommendations for the
Double Vee Device: In the coolest weather possible, core a 6-inch- (152-millimeter-) diameter
hole centered over the joint or crack (Figure 10.3.), with the core hole extending entirely through
the slab depth. The core sidewalls should be grooved to assist in creating a mechanical interlock
(Figure 10.4.). The core hole sidewalls are then roughened by sandblasting and brushed clean to
keep dust from interfering with bond of the patch material with the existing slab. The joints or
cracks and the bottom of the core hole must be completely sealed to prevent loss of the liquid
portion of the polymer concrete. The precompressed Double Vee Device is inserted (Figure
10.5.) and properly oriented with the joint or crack at a depth of 1 inch (25 millimeters) below the
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