ITEM 621  RAISED PAVEMENT MARKERS (RPM)

621.01   Description
621.02   Materials
621.03   Layout
621.04   Installation
621.05   Reflector Replacement
621.06   Reflector Color
621.07   Method of Measurement
621.08   Basis of Payment

621.01  Description.  This work consists of preparing the pavement and furnishing and placing plowable raised pavement markers (RPMs) and prismatic retroreflectors.

When the Contract Documents require the use of recycled RPMs, conform to Supplement 1082 for pickup and transfer procedures

621.02  Materials.  Furnish materials from the Department’s Prequalified List conforming to the following:

621.03  Layout.  Before placing RPMs, lay out the location of all RPMs.  Locate RPMs within 5 percent of specified spacing.  Do not place RPMs under the following conditions:

A.     On pavement surfaces with cracking, spalling, or failure of underlying base material.
B.      Within 1 foot (0.3 m) of active signal detector loop wires.  Exercise care to ensure that detector lead-in cables are not cut.
C.     Over pavement markings except with the Engineer’s approval.
D.     At a pavement construction joint or within an intersection.
E.      Within 3 feet (1 m) of a bridge expansion joint.

If the initial location of a RPM is determined to violate one of the aforementioned conditions, relocate the affected RPM longitudinally.  Relocate the RPM within a distance not exceeding 25 percent of the specified RPM spacing.  If necessary to relocate the RPM to a distance greater than 25 percent of the specified RPM spacing, do not install the affected RPM.

Center the RPMs along double yellow centerline between the two painted lines.  Place RPMs installed along an edge or channelizing line so that the marker casting is no more than 1 inch (25 mm) from the edge of the painted line.  Place the RPMs installed along a lane line or dashed yellow centerline between and in line with the dashes.

Install replacement RPMs within 1 foot (0.3 m) longitudinally of the damaged or missing RPM.

621.04  Installation.  Cut parallel slots into the pavement for installing RPM castings.  Remove residue or loose material resulting from the cutting operation from the pavement.

Install the RPM casting within 24 hours after cutting the slots into the pavement.  On new pavement surfaces, the Contractor may begin RPM placement as soon as the pavement markings for that section are completed and dry.

Ensure that the RPM casting is free of dirt, dust, oil, grease, rust, moisture, or any foreign matter that impairs adhesion to the pavement.  Clean contaminated castings by sandblasting or other means approved by the Engineer.

Place RPMs when the pavement surface temperature and the ambient air temperature are at least 40 °F (5 °C) and the pavement is dry.  Heat both parts of the RPM casting adhesive to 100 ± 10 °F (38 ± 5 °C) during installation when either the pavement surface or ambient air temperature is between 40 and 50 °F (5 and 10 °C).

Do not allow traffic on the RPMs until the adhesive has cured.

Mix the casting adhesive according to the manufacturer’s recommendations.  Complete the mixing operation and placing of the RPMs rapidly.  Do not use any mixed batch that becomes so viscous that it cannot be readily extruded from under the RPM with light pressure.

Before applying the casting adhesive, clean and dry the slots of loose material.  Fill the cleaned slots with adhesive.  Place sufficient adhesive in and between the slots to ensure that all voids beneath and around the casting are filled.  Place the keels of the casting into the slots in a manner to ensure that the tips of the RPM snowplow deflecting surfaces are below the pavement surface and that all four lugs on the keels of the casting are in contact with the pavement.

Attach the reflector to the casting before installation or after the adhesive in the pavement slots has cured.  Remove all dirt, dust, oil, grease, rust, moisture, parts of damaged reflectors, or any foreign matter that impairs adhesion of the reflector to the casting.  Sandblast the reflector attachment area to at least 80 percent bare metal.  Apply adhesive in a single bead, sufficient to squeeze out on all sides when pressure is applied to seat the reflector.  Apply at least 100 pounds (45 kg) of seating pressure.  Do not apply adhesive material on the reflective surface of the reflector.  Apply the reflector when the pavement surface temperature and the ambient air temperature are at least 40 °F (5 °C) and the casting surface is dry.  Do not attach the reflector to the casting when rain over the work site is imminent.

621.05  Reflector Replacement.  Replace damaged, non-retroreflective, or missing reflectors within the existing marker installations where the casting remains intact with the appropriate reflector type.  The Engineer will determine the location of replacement reflectors.

Perform the cleaning and attachment procedure for replacing reflectors within existing RPM installations according to 621.04.

621.06  Reflector Color.  Use the appropriate reflector color for the following applications:

A.     Channelizing Lines.  White one-way reflectors facing traffic.

B.     Lane Lines.  White one-way or white/red two-way reflectors as specified, with white facing traffic.

C.     Edge Lines.  One-way reflectors facing traffic matching the edge line color or two-way reflectors with the edge line color facing traffic and red in the opposite direction.

D.     Center Lines.  Yellow two-way reflectors.

621.07  Method of Measurement.  The Department will measure RPMs by the number of each furnished, complete with reflectors, in place, and accepted.

The Department will measure RPM Casting, Installation Only by the number of each supplied by the Department excluding an attached reflector, complete in place and accepted.

The Department will measure RPM, Installation Only by the number of each supplied by the Department including an attached reflector, complete in place and accepted.

The Department will measure RPM, Reflectors by the number of each, complete in place, for use on Department furnished castings or on existing RPM castings in the pavement, and accepted.

621.08  Basis of Payment.  The Department will pay for accepted quantities at the contract prices as follows: