Details:

Creators:
Moser, Robert ; Holland, R. Brett ; Kahn, Lawrence ; Singh, Preet ; Kurtis, Kimberly
Moser, Robert ; Holland, R. Brett ; Kahn, Lawrence ; Singh, Preet ; Kurtis, Kimberly Less -
Corporate Creators:
Georgia Institute of Technology. School of Civil and Environmental Engineering
Corporate Contributors:
Georgia. Dept. of Transportation. Office of Materials & Research
Subject/TRT Terms:
[+]
Concrete Bridges Corrosion Resistant Materials Piles (Supports) Precast Concrete Precast Prestressed Concrete Piles Prestressed Concrete Seawater
Resource Type:
Tech Report
Geographical Coverage:
Georgia
Corporate Publisher:
Georgia. Department of Transportation. Office of Research
Abstract:
Research conducted in Part 1 has verified that precast prestressed concrete piles in Georgia’s marine environment are deteriorating. The concrete is subjected to sulfate and biological attack and the prestressed and nonprestressed reinforcement is corroding. Concrete is reported as “soft” in many bridges; and exterior cracking indicates reinforcement corrosion. Researchers reviewed concrete durability and reinforcement corrosion research and experiences. These reviews gave the necessary background to evaluate the condition of Georgia’s prestressed concrete piles and to establish future tests for strand corrosion and for concrete mix design experiments. Based on discussions with the Bridge Maintenance Engineer, four 40-ft lengths of piles were removed from the Turtle River Bridge and transported to Georgia Institute of Technology. The forensic examination of the piles indicated that after 32 years in service, the concrete within the water had suffered from biological attack by sponges which consumed the limestone aggregate, and the cement had deteriorated due to sulfate attack. Prestressing strands and tie reinforcement had severely corroded in splash zones due to high levels of chloride. Concrete above water was in good condition. Experiments on the corrosion resistance of typical A416 prestressing strand wire and on 7-wire prestressing strands were conducted. Solutions represented various chloride conditions; concentrations varied from none to twice that of seawater. Georgia marsh conditions have an average chloride content about one-half that of open seawater. For wire in good quality, noncarbonated concrete, corrosion is very limited. In carbonated concrete, corrosion starts quickly at low chloride concentrations. The experiments further showed that prestressing strands exhibit a 60-70% reduction in corrosion resistance when compared with wires and reinforcing bars because of crevices created in the stranded geometry. Future experiments must consider such crevice corrosion. Most of the past corrosion research did not consider this effect of crevice corrosion due to stranding. Six alloys of stainless steel were considered for potential use as prestressing wire and strand. Most stainless steels are not capable of developing the high strength needed for prestressing applications. Change in structure of the steel due to cold drawing has the potential for making the steel very susceptible to corrosion. Further, stainless steels such as the nitronic 33 used in older Navy piles have high stress relaxation. While all six will be investigated in Part 2, the most promising alloys are 2205 and 2304. Such stainless steel prestressing strands seem to be the best solution for providing durable piles in the marine environment.
Format:
PDF
Funding:
GDOT Research Project No. 07-30 ; Task Order No. 02-55
GDOT Research Project No. 07-30 ; Task Order No. 02-55 Less -
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:53a6343ed62ac42c6d1571fb81525dd237ab0b20fd6d8a2780b7b8d80159ce6e
Download URL:
https://rosap.ntl.bts.gov/view/dot/20616/dot_20616_DS1.pdf
File Type:

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