specified strength requirement. If the core tests are inconclusive or
impractical to obtain, or if structural analysis does not confirm the
safety of the structure, load tests may be directed by the Contracting
Officer in accordance with the requirements of ACI 318/318R. Concrete work
evaluated by structural analysis or by results of a load test and found
deficient shall be corrected in a manner satisfactory to the Contracting
Officer. All investigations, testing, load tests, and correction of
deficiencies shall be performed, and approved by the Contracting Officer,
at the expense of the Contractor.
3.2
PREPARATION OF CONCRETE SURFACES
3.2.1
Initial Surface Cleaning
The cleaning materials, equipment, and methods shall not result in
staining, erosion, marring, or other damage to the surfaces of the
structure. The materials, equipment, and methods proposed for use in
cleaning shall be demonstrated in a 1 by 1 m 3 by 3 foot square test
section. The location of the test section, and the completed test section
shall be subject to approval. The cleaning process shall be adjusted as
required and the test section rerun until an acceptable process is
obtained. Following an initial inspection and evaluation of the structure
and surfaces, the structure shall be given an initial surface cleaning.
The initial surface cleaning shall be completed prior to start of
excavation, and sampling and testing for mixtures. The initial cleaning
shall provide for the complete cleaning of all exterior concrete surfaces
of the structures. The initial cleaning shall thoroughly clean the
concrete surface to remove all traces of moss, dirt, and other
contaminants. The cleaning shall provide a clean concrete surface to allow
determination of the concrete's color and shades, finish and texture, and
other properties. The "initial cleaning" shall consist of initial surface
washing, followed by treatment with the cleaning solution, and then
followed by a final water rinse. The initial surface washing shall consist
of washing the surface with clean, low pressure water (pressure of less
than 0.38 MPa 55 psi and 9.5 to 11.4 L/minute 2.5 to 3 gpm discharge) and
manual surface scrubbing using handheld natural or plastic bristle brushes,
followed by a clean water rinse. Following completion of the initial
surface washing of the entire structure (or side of structure) the concrete
shall be dried prior to application of the cleaning solution. The concrete
surfaces of the structure shall be coated with the cleaning solution at an
application rate of 3.8 L 1 gal of solution per 1 to 3 square meters 10 to
30 square feet of treated surface using low pressure spraying equipment.
The application rate of the solution shall be adjusted as directed to
ensure that the entire surface has been thoroughly wetted with the
solution. A manual surface scrubbing with handheld natural or plastic
bristle brushes shall be used on heavily soiled areas. Following treatment
with the cleaning solution the treated surfaces shall be rinsed with clean,
low-pressure water. Water and all liquid materials used in the work shall
be contained at the building perimeter and collected and disposed of in an
approved manner.
3.2.2
Areas to be Removed
Unsound, weak, or damaged concrete shall be removed. Loose particles,
laitance, spalling, cracked, or debonded concrete and foreign materials
shall be removed with hand tools unless otherwise noted. Surfaces of the
structure, and surfaces adjacent to the excavation shall be protected from
damage which may result from excavation, cleaning, and patching operations.
SECTION 03900
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