UFC 3-270-01
15 March 2001
for the revolutions per minute (RPM) of the saw; otherwise, the blade could shatter during sawing
if the blade does not have the correct RPM rating.
3.2.3. Jackhammer and remove defective material. An asphalt bit shall be used in the
jackhammer. The jackhammer should be operated from the middle of the repair area and move
toward the edges. (Do not rock the hammer near the edge -- this will destroy the vertical face.)
If a saw is not available, the perimenter of the patch can be cut with the jackhammer. Since this
method forms rough edges, it is not recommended. It is important that the cuts around the
distress should be as vertical as possible. After jackhammering, remove and discard the loose
material.
3.2.4. Remove, replace, and compact the base. When performing a full-depth patch, the base
should be visually inspected to ensure that the condition of the material is adequate. All
inadequate base, subbase, or subgrade materials should be removed until a good, dry, and
dense material is located. The poor-quality material shall be replaced with a good-quality,
well-graded base material. If subgrade material is removed, crushed stone or other suitable base
material may be used to backfill to the top of the subgrade. New materials shall be placed in 2- to
3-inch (50- to 75-millimeter) lifts with each lift compacted to the required density. When removing
the defective pavement, the base material is always disturbed. Therefore, the base material
should always be recompacted prior to performing the next step.
3.2.5. Apply tack coat (and prime coat if used). A prime coat can be used to spray the sides and
bottom of the hole to be patched with hot-asphalt plant mix. Recommended prime coat materials
are RC-70, MC-30, MC-70, or SC-70 cutback; an SS-1, SS-1h, CSS-1, or CSS-1h emulsion. The
application rate is 0.10 to 0.25 gallons per square yard (0.45 to 1.13 liters per square meter). Too
heavy an application could cause bleeding. Prime coats must be allowed time to penetrate the
base material. They are usually absorbed in 2 to 3 hours and should be fully cured in up to
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