3.2.2
Concrete on Earth Foundations
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NOTE: The Designer should insert the appropriate
Section number and title below.
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Earth surfaces upon which preplaced-aggregate concrete is to be placed
shall be clean, damp, and free from debris, frost, ice, and standing or
running water. Prior to placement of coarse aggregate, the earth
foundation shall have been satisfactorily compacted in accordance with the
provisions of [Section [_____]] [_____].
3.2.3
Concrete on Rock Foundations
Rock surfaces upon which coarse aggregate for preplaced-aggregate concrete
is to be placed shall be clean, free from oil, standing or running water,
ice, mud, drummy rock, coating, debris, and loose, semidetached, or unsound
fragments. Joints in rock shall be cleaned to a satisfactory depth, as
determined by the Contracting Officer, and to firm rock on the sides.
Immediately before the coarse aggregate is placed, all rock surfaces shall
be cleaned thoroughly by the use of air-water jets or sandblasting as
defined in paragraph CONSTRUCTION JOINT TREATMENT.
3.2.4
Underwater Placement
Coarse aggregate for underwater preplaced-aggregate concrete shall be
placed on rock surfaces which are clean, free from drummy rock, coatings,
debris, and loose semidetached or unsound fragments.
3.2.5
Concrete Surfaces
Concrete surfaces on which coarse aggregate is to be placed or
preplaced-aggregate concrete surfaces between stages shall be clean and
free from foreign material. Excessive accumulation of fine material on the
surface shall be removed with high-pressure water jets or other approved
methods.
3.2.6
Construction Joint Treatment
3.2.6.1
a. If grout in a preplaced-aggregate placement is not brought to the
surface in order to form a construction joint, the intrusion grout rise
shall stop 300 mm 12 inches below the aggregate surface. Dirt and
debris shall not be allowed to collect on the aggregate surface or
allowed to filter down to the grout surface. The insert pipes shall be
pulled just above the grout surface before the grout stiffens and
rodded clear. When pumping is ready to resume, the insert pipes shall
be worked back to near contact with the hardened grout surface and then
pumping slowly resumed for a few minutes.
b. Preplaced-aggregate concrete in which the grout has been brought to
the surface and any other concrete surfaces to which
preplaced-aggregate concrete is to be bonded shall be prepared for
receiving the next lift or adjacent preplaced-aggregate concrete by
cleaning with air-water cutting, sandblasting, high-pressure water jet,
or other approved method. Air-water cutting will not be permitted on
SECTION 03372
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