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INITIAL REPORT STOPPING ACTIVE CREVICE
CORROSION On a Big Conestoga #9 ( By High Pressure (5,000 psi) and Overcoating with the Termarust high ratio co-polymerized calcium
sulfonate coating
system
For Cleaning & Coating by P.S. Bruckel, Inc, Coating Materials from Termarust Technologies, Project Painting Date: October -
November, 2008 INITIAL REPORT By: Craig A. Ballinger, P.E. Termarust Technologies Phone: 888-279-5497 [then
press 4] Email:
cballinger@termarust.com OVERVIEW This report provides some
information and pictures of the cleaning and Termarust coating work that was
done on this bridge in October and November, 2008, for Lancaster County Pennsylvania. The bridge, which was built
in the 1923, was found to have been painted with a lead-based paint system,
that had failed and corrosion of the steel members had caused structural
problems; especially on the steel members that support the steel grid decking: ·
Heavy scale rust had caused loss of section
(thickness) of flanges and webs of members ·
At the East end of the bridge the ends of several
longitudinal members there were large holes in the webs of the beams (that were
strengthened by welding plates to the webs). ·
There was some crevice corrosion and pack rust
development in some connections between steel members. It is
important to note: 1.
The
contract required and specified use of 5,000 psi pressure water wash cleaning
and application of the Termarust (or equal) high ratio calcium sulfonate coating
system to chemically stop further development corrosion; including
crevice corrosion. 2.
The
contract required a joint (Contractor-coating manufacturer) 5-year warranty
against coating system failure with no exclusions; e.g. for inaccessible
areas, such as where crevice corrosion has occurred or could occur. This
requirement was primarily based on the 15+ year field-proven history of the
Termarust coating system to stop active corrosion with no warranty claims for
similar 5-year warranties and the
successful use of this type of cleaning and coating on the Pennsylvania
Turnpikes Hawk Falls Bridge on I476 at MP 88.59 in April, 2008. 3.
Several factors led to the substantial cost savings for using 5,000 psi pressure wash cleaning and
application of the Termarust coating system vs. the expected costs for
sandblast cleaning and the use of a traditional 3-coat, zinc-based coating
system that does not have the chemistry to chemically stop active corrosion,
including:
·
The
reduced amount of, and cost for disposal of hazardous (lead paint) waste
materials. REFERENCES Consultant to Rettew Associates, Inc. Contact
Person: Quentin Rissler Phone: 717-394-3721 Painting Contractor P.S. Bruckel, Inc., Contact Person: Peter Bruckel CLEANING AND APPLICATION PROCEDURES The following standard Termarust
procedures were specified and followed: 1. Pressure wash clean the bridge with a
5,000 psi pressure washer (at a 6 standoff distance) with clean water with an
additive of Chlor*Rid to remove non-visible salts; e.g. chlorides. (For
more information on Chlor*Rid see www.chlor-rid.com) 2. Blow dry all connections with dry
compressed air. 3. Apply the Termarust TR2200 Penetrant
into all connections between steel members; where there is (or could develop)
crevice corrosion and pack rust. 4. Apply a caulk (or stripe) coat of
Termarust TR2100 Topcoat onto areas where the TR2200 Penetrant had been applied
minimum 10 mils dry film thickness (DFT). 5. Spot prime areas of bare steel and
tightly adhered (contaminant free) rust with 5 mils DFT of Termarust TR2100
Topcoat 6. Overcoat the entire area with another 5
mils DFT of TR2100 Topcoat. It is important to note
that steps 3 through 6 may be done immediately after each other; i.e.
wet-on-wet; which is why the Termarust system is considered to be a One Coat
system. The final result was: ·
5
mils DFT on tight paint, ·
10
mils DFT on bare steel and tight rust, and ·
20
mils DFT over connections. PICTORIAL OVERVIEW The following pictures provide a pictorial overview
of the project.
Photo 1 Bridge before cleaning and coating with the
Termarust system.
Photo 2 Upper portion of the truss showing
corrosion and some pack rust.
Photo 3 View of outside of the truss, before
cleaning and coating with Termarust
Photo 4 The underside of one span of the truss,
before cleaning and coating with Termarust.
Photo 5 Underside of the deck, at the pier. The ends of four of the longitudinal beams
had corrosion-caused holes in the webs.
The webs were strengthened by welding plates to both sides.
Photo 6 Containment for pressure wash cleaning and collection of lead paint containing chips of
paint and corrosion debris
Photo 7 After pressure washing loose paint and
loose corrosion debris has been removed.
Photo 8 Work platform Containment tarps were
removed after pressure washing.
Photo 9 After pressure washing only tight paint and
tight clean rust remains
Photo 10 After pressure washing some scale rust
remains on some members under the deck, which must be mechanically removed,
because there is active corrosion under it.
Photo 11 Example of scale rust that remained after
pressure washing; and which was removed.
Photo 12 Bridge members have been coated with the
Termarust system
Photo 13 Close-up of a complex connection (See
Photo 7)
Photo 14 Coating has been completed (See Photo 2)
Photo 15 Coating has been completed (See Photos 8
and 9)
Photo 16 Coating has been completed and corrosion
stopped. (See Photos 4, 5 and 10) |
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