UFC 3-250-03
15 May 2001
mixing drum at the maximum allowable revolutions per minute. The final control on the acceptability of
the mixing process is the mixing of a consistent grout which will meet the viscosity requirements.
(2) Placement.
(a) Application of grout. The surface temperature of the bituminous mixture shall be less
than 38 degrees C (100 degrees F) before applying grout. On hot days, this will require the use of a fog
spray of water to reduce the temperature. Excessive amounts of water that cause ponding shall not be
used. Each batch of grout should be tested at the jobsite immediately before placement and shall be
used in the finished product only if it meets the viscosity requirements listed in table 8-5. The cement
grout is poured over the bituminous mixture from the ready-mix truck by means of a pivoting delivery
chute and then spread around with the hand squeegees. The application of the cement grout should be
sufficient to fill the internal voids of the open-graded bituminous mixture. The grouting operation should
begin at the lowest side of the sloped cross-section and proceed from the low side to the high side. It
should be noted that slopes up to 2 percent are considered the practical limit for RMP. Sections with
slopes up to 5 percent have been placed but excess hand work and grout overruns can be expected at
slopes greater than 2 percent. The slurry grout should be placed in successive paving lanes with a
maximum width of 6 meters (20 feet). The use of 50 millimeter (2-inch) by 100 millimeter (4-inch) strips
of lumber as wooden battens separating each of the grouting lanes and the RMP from adjacent
pavements will facilitate an orderly grouting operation. Secure the wooden battens to the surface of the
bituminous mixture before grout application to help prevent excessive grout runoff and to prevent
overworking the grouting crew. The direction of the grouting operation should be the same as used to
pave the open-graded bituminous mixture. The small (3-metric ton (3 ton) maximum) tandem steel
wheel roller (vibratory mode) passing over the grout covered bituminous mixture shall be used to
promote full penetration of the slurry grout into the void spaces. Once the open-graded layer is fully
saturated with grout, all excess grout is removed by squeegeeing. This process will expose the rough
surface of the open-graded material and improve skid resistance.
(b) Joints. The formation of all joints between successive lanes of RMP should be made in
such a manner as to ensure a continuous bond between the paving lanes. The wooden battens should
be removed as soon as the grout has been applied to the surrounding area and the area underneath
them vibrated or reworked with additional grout and hand brooms to assure full penetration and
smoothness in these joint areas. There are no time restrictions for placing successive lanes of grout in
order to create proper joints. All RMP joints should have the same texture, density, and smoothness as
other sections of the course. The joints between the RMP and any surrounding pavement surfaced with
portland cement concrete should be saw cut to one-half of the RMP thickness and filled with a joint
sealant material approved by the contracting officer.
(3) Curing. Proper curing of a new RMP surface is accomplished with a light coating of a white-
pigmented, membrane-forming curing compound. The curing compound should be applied to the
finished pavement surface while the surface is still damp but without excessive moisture on the surface,
normally within 2 hours of the completed slurry grout application. The curing compound shall be applied
by means of an approved pressurized spraying machine. Application of the curing compound shall be
made in one or two coats with a total application rate of 4.5 square meters per liter (200 square feet per
gallon).
(4) Covering pavement surface.
(a) Prior to grouting. The contractor should protect the ungrouted pavement and its
appurtenances against contamination from mud, dirt, wind blown debris, water born material, or any
other contamination which could enter the void spaces of the open-graded asphalt mixture before grout
application. Protection against contamination shall be accomplished by keeping the construction site
8-6
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