TM 5-822-11/AFP 88-6, Chap. 7
e. Waterblasting. Waterblasting has been used
clean the crack and to form a sealant reservoir
successfully in areas where sandblasting was not
with a minimum amount of spalling. Vertical
permitted due to local atmospheric pollution stat-
spindle routers may be used in asphalt and, to a
ues or when the sand could drift into areas where
limited extent, in PCC the vertical spindle router
it would be objectionable. The waterblasting
can become jammed in the pavement if the opera-
equipment must include a trailer-mounted water
tor tries to force the router along the crack. This
tank, pumps, high-pressure hoses, auxiliary water
is especially true when the router is used in PCC
resupply equipment, a wand with a safety release
pavements. It is therefore important that the bit be
cutoff control, and nozzle of the proper size for
belt driven to prevent injury to the operator if the
the joints in the pavement. The use of
bit becomes jammed.
waterblasting equipment must comply with
(2) Rotary impact routers are equipped with
occupational and health standards at all times.
bits that are mounted to a vertical wheel that
Protective clothing must be worn by the operator
rotates forcing the bits to impact the pavement.
at all times. The nozzle should be adjustable to
Rotary impact routers should not be used on PCC
obtain satisfactory results. Waterblasting
pavement. Rotary impact routers spall the PCC
equipment is shown in figure 4-5.
adjacent to the crack, damaging the pavement and
f. Routing Equipment. There are two types of
producing an inadequate sealant reservoir. How-
routing equipment that may be used on sealing
ever, rotary impact routers equipped with carbide
projects; the vertical spindle router (fig 4-6) and
tipped bits (fig 4-8) may be used to rout cracks in
the rotary impact router (fig 4-7).
bituminous pavement. The rotary impact routers
(1) The vertical spindle router is equipped
equipped with carbide tipped bits provide a rela-
with a bit that rotates around its vertical axis
tively quick method to form an adequate sealant
similar to a drill. The spindle is mounted on the
reservoir. If carbide tipped bits are not used, the
chassis in such a manner that it can maneuver
router can damage pavement surfaces adjacent to
along the irregular dimensions of the crack to
the crack. Rotary impact routers, even equipped
4-3
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