621Raised Pavement Markers (Rpm)

621.01 Description. This work consists of preparing the pavement and furnishing and placing

plowable raised pavement marker castings (RPMs) and prismatic retroreflectors, and removing existing RPMs for disposal.

621.02 Materials. Furnish materials conforming to :

Castings ............................................ 721.01 Prismatic Retroreflectors and Adhesive ....................................... 721.02 Casting adhesive .............................. 721.03

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:

621.04 Installation RPM Casting. Cut parallel slots with 1/16 to 1/8 inch clearance on each side

for installing RPM castings. Pavement cuts should be inspected prior to adding casting adhesive. Test for a proper fit by inserting the casting in the center of the cut without casting adhesive. While sitting untouched in the cut, ensure all four leveling lugs contact the pavement surface at once, all four keel-ends lie below the pavement surface, and a there is a 1/16 to 1/8 inch clearance between pavement cut and casting edge on each side for casting adhesive to bond properly. Only the leveling lugs should be in contact with the pavement surface after insertion of casting in pavement so that a minimum of 1/16 inch of casting adhesive is the bonding adhesive between the casting and pavement. Ensure the pavement cut is completely dry and free of dust, dirt or any other material that will interfere with the adhesive bond to the casting and the pavement. Ensure that the RPM casting is free of dirt, dust, oil, grease, rust, moisture, or any foreign matter that impairs adhesion to the pavement. Do not cut RPM casting slots if adjacent pavement markings are not completely dry. Install the RPM casting within 24 hours after cutting the RPM casting slots. Install RPM castings when the pavement surface temperature and the ambient air temperature are at least 40 F and the pavement is dry. Heat both parts of the RPM casting adhesive to 100  10 F during installation when either the pavement surface or ambient air temperature is between 40 and 50 F. Ambient Air Temperature Minimum Period Protected from Traffic F (C) Minutes 100 (38) 15 90 (32) 20 80 (27) 25 70 (21) 30 60 (16) 35 50 (10) 45 40 (5) 60 Do not allow traffic on the RPMs until the adhesive has cured. Using approved two component casting adhesive, mix according to the manufacturer’s recommendations. Fill the pavement cut to within approximately 3/8 inch of the top of the pavement cut. The casting adhesive should ooze out from under the casting from all sides filling all voids around the casting and be level with the pavement surface and without any build -up on the casting lips in front of the reflector. Casting adhesive on the casting lips or on the active reflector face must be removed immediately. 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.

621.05 Installation RPM Retroreflector. 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. Peel the release liner from the back of the reflector with butyl pad. Apply a wide bead (approximately 3/8 inch (9 mm)) of reflector adhesive sufficient to squeeze out on all sides when pressure is applied to seat the reflector. Apply approximately 100 pounds (45 kg) of pressure on the reflector or foot pressure for 1 to 3 seconds. Do not allow adhesive material on the reflective surface of the reflector. Any adhesive on the active reflector must be removed immediately. Apply the reflector when the pavement surface temperature and the ambient air temperature are at least 35 F (2 C) and the casting surface is dry. Do not attach the reflector to the casting when rain over the work site is imminent.

621.06 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 621.05.

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

621.08 Raised Pavement Markers Removed. As designated, remove existing raised pavement

markers. Fill all depressions caused by removing the castings with asphalt concrete by the end of the next workday. Remove all standing water from the hole, clean the hole, and coat with 407.02 asphalt material before filling . Compact the asphalt concrete flush with the pavement. Removed raised pavement markers become the property of the Contractor.

621.09 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, Reflectors by the number of each, complete in place, for use on existing RPM castings in the pavement, and accepted. The Department will measure Raised Pavement Markers Removed by the number. Payment will include the cost of asphalt concrete to fill depressions caused by removal of the castings.

621.10 Basis of Payment. The Department will pay for accepted quantities at the contract prices

as follows: Item Unit Description 621 Each RPM 621 Each RPM Reflector 621 Each Raised Pavement Marker Removed