UFC 3-270-02
15 March 2001
CHAPTER 8
CRACK SEALING EQUIPMENT
8.1. Hot-Applied Sealant Equipment. At the present time, most asphalt pavement crack
sealants are hot-applied. If a cold-applied sealant is used, the equipment requirements should be
obtained from the sealant manufacturer. Some of the items of equipment used when sealing
cracks with a hot-applied sealant are described below:
8.1.1. Hot-applied sealant applicator (melter). The equipment used to heat and install the
hot-applied sealant (Figure 8.1.) should consist of a double-boiler, agitator-type kettle. The heat
transfer medium in the outer space should be an oil with a high flash point. The double-boiler
helps eliminate hot spots in the heating kettle and the agitator provides mixing for uniform heating
of the sealant. A direct heating kettle should never be allowed. The sealant should be
transferred from the kettle to the crack by means of a direct-connected pressure-type extruding
device (hose) with a nozzle that will insert into the crack. The equipment should be designed to
allow the sealant to be circulated back into the inner kettle when sealing is not being performed.
Positive temperature devices are used to control the temperature of the oil bath and measure the
temperature of the sealant. Recording-type thermometers are useful for monitoring the
temperature of the sealant in the kettle as work progresses. Recording-type thermometers are
not normally installed on the equipment at the manufacturer, but can be installed by the
Contractor. The thermometers should be positioned so that they are easily read. Figure 8.2.
shows the normal type of thermometers used on the melter.
8.1.2. Handtools. Due to the meandering nature of cracks, handtools are required to insert the
backer rod materials in cracks that are deeper than 3/4 inch (19 millimeters). These tools should
not twist, cut, or damage the backer rod material.
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