15 March 2001
directed at the other joint face, and it is sandblasted for the entire length of the slab. The
pavement surface adjacent to the joint is then sandblasted to remove all surface debris. If
waterblasting is used instead of sandblasting, a multiple pass technique should still be employed
and the joints will have to be dry before the sealing operation continues. Cleaning the joint is one
of the most important steps in obtaining a high-quality sealing project. If the joints are not clean
and dry before the sealant is installed, the sealant will usually fail prematurely.
4.15.4. After the joint has been sandblasted, it must be cleaned with compressed air to remove
any remaining sand or dust. However, the final air cleaning of the joint should be completed
immediately before sealing to prevent more sand and dust from blowing back into the joint. A
vacuum sweeper can be used to clean around the joints, which will help reduce the amount of
debris that blows back into the joints.
4.15.5. After the joint is cleaned, the backer rod or separating material should be installed. The
backer materials should not be left in the joint for an extended period of time before sealing. The
materials may work loose and move up or down in the joint or may even come completely out.
These materials must not be twisted, stretched, or otherwise damaged when they are installed in
the joint. Damaging the backer material can cause sealant failure or a poor quality finished
product. The backer rod or separating material should be inspected after installation to ensure
that it has been placed at the proper depth and has not been damaged. After installation of the
backer or separating material, the joint is ready for the sealant material. However, the joint
should be sealed only if all steps have been performed properly.
4.15.6. Sealants must conform to one of the following ASTM specifications: D 1752, D 2628,
D 3405, D 3406, D 5893, or D 3569 if the repair is located in an area where fuel, lubricating, or
hydraulic fluid spillage may occur.