31 Dec 96
between 0.65 and 0.75, which provides a very fluid consistency.
The cement grout material can be produced in a conventional
concrete batch plant or a small portable mixer. After the
asphalt mixture has cooled, the grout is poured onto the
open-graded asphalt layer and squeegeed over the surface. The
grout is then vibrated into the voids with the 3-tonne vibratory
steel-wheel roller to ensure full penetration of the grout. This
process of grout application and vibration continues until all
voids are filled with grout.
(2) Depending upon the specific traffic needs, the freshly
grouted surface may be hand broomed or mechanically textured to
improve skid resistance. In most circumstances, however, the
excess grout is squeegeed off of the pavement surface, and a
natural rough texture is achieved through evaporation of surface
bleed water. Spray-on curing compounds, typical to the PCC
industry, are generally used for short-term curing. The new RMP
surfacing usually achieves full strength in 28 days, but it may
be opened to pedestrian traffic in 24 hours and light automobile
traffic in 3 days.
c. Pavement Design. The pavement thickness for the RMP is
to be determined using flexible pavement criteria. The total
pavement thickness for a pavement structure including the RMP
should be determined using TM 5)822)5 and TM 5)825)2. After the
pavement thickness has been determined for a particular load and
level of traffic, the top 50 mm of the asphalt concrete layer are
to be replaced with 50 mm of the RMP. This is a conservative
design approach, but pending the outcome of further research in
this area, all RMP projects should be designed as a conventional
flexible pavement in this manner.
(1) In rehabilitation projects such as overlays, the overlay
pavement thickness should be determined to satisfy traffic and
load requirements. The minimum overlay thickness is 50 mm when
using the RMP. If additional thickness is required, the
remaining pavement thickness underlying the RMP surface should
consist of high-quality asphalt concrete.
(2) RMP has been successfully constructed as an overlay
material over rigid and flexible pavements as well as in original
construction. No transverse or longitudinal joints are required
for original, full-depth RMP designs although joints have been
cut in RMP when overlaying jointed PCC pavement. Cracking and
seating of existing PCC and then overlaying with an AC interlayer
and RMP surfacing has been a successful design approach.
Pavement joints are required between RMP and adjacent PCC
pavements but are not required between RMP and adjacent AC