UFC 3-270-03
15 March 2001
CHAPTER 10
CRACK PREPARATION
10.1. Description. One essential element of the crack sealing operation is proper preparation of
the crack and the crack face. If the prepared cracks are dirty or contain excess moisture, the
sealant will not adhere to the surface and eventually will separate from the crack wall. The crack
sealing operation must be scheduled such that the prepared cracks are sealed as soon as
possible to prevent contamination before sealant application. If vegetation is growing in the
cracks, they must be removed and a water-based herbicide must be used to kill the weeds.
Oil-based herbicides can leave a residue that may prevent adhesion of the sealant to the crack
face. The cracks must be routed or sawed out to the proper depth and width according to the
shape factor previously listed or designated by the manufacturer's recommendations for the
particular sealant being employed (Figures 10.1. and 10.2.). After completion of the sawing
operation, the crack face must be sandblasted to remove laitance, sawing debris, and other
foreign material. Sandblasting must be conducted with a multiple-pass technique in which one
side of the sawed crack face is abraded, followed by the other face (Figure 10.3.). The pavement
surface directly adjacent to the sawed crack must also be blasted to remove any debris or
material that may cause problems during crack sealing.
10.2. Cleaning. The importance of proper cleaning of the crack faces cannot be
overemphasized. Surface dust, debris, and laitance remaining in the sawed crack can prevent
adhesion of the crack sealant to the prepared face. The sandblasting operation must be followed
by an initial cleaning with high-pressure air followed by high-pressure water to remove material
remaining in the sawed cracks. This process must be repeated immediately prior to placing the
sealant in the sawed reservoir if the sealant is not placed within a few hours of the cleaning. A
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