Test Report for Accelerated Aging of Weathering Steel ... - TurnaSure
Test Report for Accelerated Aging of Weathering Steel ... - TurnaSure
Test Report for Accelerated Aging of Weathering Steel ... - TurnaSure
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(412) 788-1300<br />
(412\ 788-1306 Fax<br />
http://www.kta.com<br />
e-mail: info@kta.com<br />
KTA.TATOR, lNG.<br />
115 Technology Drive, Pittsburgh, PA 15275<br />
February 8,2002<br />
Mr. Jonathan Turner<br />
<strong>TurnaSure</strong> LLC<br />
340 E. Maple Avenue, Suite 305<br />
Langhorne, PA 19047<br />
SUBJECT:<br />
KTA-Tator,Inc. <strong>Test</strong> <strong>Report</strong> <strong>for</strong> <strong>Accelerated</strong> <strong>Aging</strong> <strong>of</strong><br />
<strong>Weathering</strong> <strong>Steel</strong> Joint - <strong>TurnaSure</strong> Project No. 210756<br />
Dear Mr. Turner:<br />
In accordance with KTA-Tator, Inc. Proposal PN011969 and <strong>TurnaSure</strong> LLC Purchase Order No.<br />
PO384, KTA-Tator, Inc. (KTA) has completed 500 hours <strong>of</strong> accelerated aging testing <strong>of</strong> the weathering<br />
steel joint. This report contains a description <strong>of</strong> the accelerated test conditions and the results <strong>of</strong> the<br />
evaluation <strong>of</strong> the weathering steel joint after 500 hours <strong>of</strong> testing.<br />
TEST SPECIMEN<br />
The test specimen consisted <strong>of</strong> a weathering steel joint assembled from 2 steel plates measuring<br />
6" x 8 ll2" x 5/8" thick, sandwichedbetween 2 additional steel plates measuring 6" x17" xIl2" thick.<br />
The steel plates were fastened together with 127/8" diameter x 3" long ASTM A325 Type 3 structural<br />
bolts, each mated with a matching heavy hex nut and hardened washer. Each bolt assembly included 1<br />
ASTM F959 DTI washer produced from Type 3 weathering steel. (See Photo 1)<br />
Coatings & Corrosion Consulting r Construction Inspection I Laboratory Analysis<br />
Materials <strong>Test</strong>ing I Environmental, Health & Safety
Mr. Jonathan Turner<br />
February 8,2002<br />
(Photo I - Example <strong>of</strong> Fastener Set Used <strong>for</strong> <strong>Test</strong>)<br />
The weathering steel joint test specimen was designed and constructed in accordance with<br />
<strong>TurnaSure</strong> LLC instructions by High <strong>Steel</strong> Structures, Inc. <strong>of</strong> Lancaster, PA and assembled at Laboratory<br />
<strong>Test</strong>ing, Inc. (LTI) <strong>of</strong> Hatfield, PA. The test joint design was intended to simulate a typical joint <strong>of</strong> a steel<br />
highway bridge. (See Photos 2 through 5, provided courtesy <strong>of</strong> LTI.)<br />
@hoto 2 - Cross-section <strong>of</strong> joint be<strong>for</strong>e Tightening)
Mr. Jonathan Tumer<br />
February 8,2002<br />
@hoto 3 - Joint Assembly using Torque Multiplier)<br />
(Photo 4 - Tightened joint dfeeler-gages in residual DTI gaps)
Mr. Jonathan Turner<br />
February 8,2002<br />
@hoto 5 - Tightened Jointdfeeler gauges in residual Steet gaps)<br />
TESTING PROTOCOL<br />
The objective <strong>of</strong> the accelerated aging testing was to determine the corrosion protection <strong>of</strong> the<br />
joint in typical atnospheric exposures. To that end, the weathering steel joint was subjected to 500 hours<br />
<strong>of</strong> cyclic testing in the Q-Fog test cabinet according to ASTM G85, *Modified Salt Spray (Fog) <strong>Test</strong>ing",<br />
AnnexA5, *Dilute Elecfolyte Cyclic Fog/Dry Tesf'.<br />
The testing consisted <strong>of</strong> exposing the specimen to continuous cycling <strong>of</strong> I hour fog at ambient<br />
temperature,z4 ! 3" c (75 + 6' F) followed by I hour d.y-<strong>of</strong>f at 35 + 1.5'c (95 + 3' F). The fog was<br />
provided by an electrolyte solution composed <strong>of</strong> 0.05% sodium chloride and, 0.35%o ammonium sulfate.<br />
The pH <strong>of</strong> the fog condensate ranged between 5.1 and 5.4 throughout he duration <strong>of</strong> the testing.<br />
The specimen was oriented in the test cabinet in the horizontal position, with one <strong>of</strong> the faces <strong>of</strong><br />
the specimen always skyward in order to enable comparisons between exposure <strong>of</strong> both a 'top flange' as<br />
well as a 'bottom flange' to 'weathering'. The test was concluded after 500 hours <strong>of</strong> exposure and the<br />
weathering steel joint test specimen was removed and disassembled <strong>for</strong> evaluation.<br />
TEST RESTILTS<br />
The weathering steel joint was carefully disassembled on bctober l7,2OOl at KTA headquarters<br />
in Pittsburgh, in the presence <strong>of</strong> Mr. Jonathan Turner and Mr. David Sharp. The condition <strong>of</strong> the<br />
specimen, prior to disassembly, was photographically documented. Photographs were also taken to<br />
document the condition <strong>of</strong> the steel plates, bolts, washers, and load indicator washers drning the entire<br />
disassembly process.<br />
The exterior surface <strong>of</strong> the joint that was oriented skyward during testing was severely rusted and<br />
covered with rust scale. It was rated as Rust Grade 0-G, (>50 o/o rusted), according to SSPC-VIS 2,<br />
"Standard Method <strong>of</strong> Evaluating Degree <strong>of</strong> Rusting on Painted <strong>Steel</strong> Surfaces". Severe rust and rust scale,<br />
also rated 0-Go was present along the sides <strong>of</strong> the joint. (See Photos 6 & 7)
Mr. Jonathan Turner<br />
February 8,2002<br />
@hoto 6 - exterior sur{ace rust) (Photo 7 - side surface rust)<br />
The exposed portions <strong>of</strong> the bolts, bolt threads, and nuts were fairly clean <strong>of</strong> rust. When the nuts<br />
were removed from the top <strong>of</strong> the joint it was noted that there was no rust between the nuts and the load<br />
indicator washers. (See Photo 8.) There was also minimal rusting, Rust Grade 4-G (10% rusted),<br />
between the bolt heads and the load indicator washers. No rust was present on the bolt shanks where the<br />
Ioad indicator washers were adjacento the bolt heads. (See Photo 9.)<br />
@hoto 8 - Lack <strong>of</strong> corrosion on DTI where it was against hex nut)<br />
@hoto 9 - Lack <strong>of</strong> corrosion on bolt shank or between load indicator bumps)
Mr. Jonathan Turner<br />
February 8,2002<br />
It was noted that any rust that was present on the load indicator washers was at the periphery <strong>of</strong><br />
the washers. An intentional gap <strong>of</strong> up to 0.005" is normally present during installation between the load<br />
indicator washer and the bolt head or the between the steel plate and the load indicator washer. The gap<br />
was not existent at the periphery <strong>of</strong> the load indicator washers, but was filled with a patina <strong>of</strong> rust<br />
measuring 0.005 inches in thickness. However, the gap remained at the interior portion <strong>of</strong> the load<br />
indicator inside the patina build-up. The area <strong>of</strong> the washer adjacent to the steel plate and/or bolt was free<br />
<strong>of</strong> any rust.<br />
Similarly, corrosion between the plates where gaps had been present appeared to become sealed<br />
<strong>of</strong>f from further corrosion upon build-up <strong>of</strong> the patina. (See Photo 10.)<br />
@hoto 10 - Patina build-up inhibited further ingress <strong>of</strong> corrosion.)<br />
Nuts removed from the top (skyrvard) side <strong>of</strong> the joint revealed clean load indicator washers free<br />
<strong>of</strong> rust on the inner portion <strong>of</strong> the washers as well as on the surface <strong>of</strong> the nuts that were adjacent to the<br />
load indicator washers. One <strong>of</strong> the bolts, when removed from the joint, was so severely rusted at the bolt<br />
head, that the top <strong>of</strong> the bolt exfoliated. The numerals designating the bolt head were still legible in the<br />
exfoliated portion <strong>of</strong> rust scale. (See Photo 11.)
Mr. Jonathan Turner<br />
February 8,2002<br />
@hoto 11 - Edoliated portion <strong>of</strong> an A325 Bolt Head)<br />
Apparently, the load indicator washers <strong>of</strong>lered protection against rusting to the bolts themselves.<br />
It was observed that many <strong>of</strong> the bolts that were fastened using the load indicator washers were free <strong>of</strong><br />
rust on the bolt shafts. In fact, it was seen that the original oil used to protecthe bolt in the field was still<br />
present on the threads at time <strong>of</strong> disassembly.<br />
The internal steel plates <strong>of</strong> the joint were approximately 50% rusted, Rust Grade l-G. The rust<br />
was also surrounding several <strong>of</strong> the bolt holes, on both the sides with and without load indicating washers.<br />
No rust was observed at the junction <strong>of</strong> several <strong>of</strong> the bolt heads with the plate due to the protection<br />
<strong>of</strong>[ered by the load indicator washers. Rust was very minimal, Rust Grade 9-G (0.03% rusted), at the bolt<br />
holes on which the load indicating washers had been present. No rust was present within 1/8" <strong>of</strong> the bolt<br />
holes at these locations, likely due to the high clamping <strong>for</strong>ces in this region. (See Photo 12.)<br />
(Photo 12 - Lack <strong>of</strong> corrosion in regions <strong>of</strong> high clamping <strong>for</strong>ce.)
Mr. Jonattran Turner<br />
February 8,2002<br />
CONCLUSIONS<br />
It became apparent, during disassembly <strong>of</strong> the joint, that the load indicator washers prevented<br />
rusting from occurring on those areas <strong>of</strong> the plate, bolt, and nut that were fastened with the load indicator<br />
washers. It was theorized that a barrier <strong>of</strong> corrosion material stopped the ingress <strong>of</strong> moisture into the<br />
0.005-inch gap present at the load indicator washer, thereby contributing to areas that were fiee <strong>of</strong><br />
corrosion and rust.<br />
If you have any questions concerning the in<strong>for</strong>mation contained in this report, please call me at<br />
412/788-1300, ext. 181.<br />
Very truly yours,<br />
KTA-TATO& INC.<br />
FAM/BRAjas<br />
Frank A. Mozelewski<br />
Senior Chemist<br />
cc:<br />
William B. Corbett<br />
Bernard R. Appleman<br />
Cynthia L. Fairfull<br />
Scott Rice<br />
JN: 210756<br />
(JAS02049<br />
NOTICE: This report represents the opinion <strong>of</strong> KTA-TATOR, INC. This report is issued in con<strong>for</strong>mance with generalty acceptable industry<br />
practices. While customary precautions were taken to insure that the in<strong>for</strong>mation gathered and presented is accurate, oomplete, and technioally<br />
conect, it is based on the in<strong>for</strong>matiorl dan4 time, materials, and/or samples af<strong>for</strong>ded