Details:

Creators:
Grace, Nabil ; Jensen, Elin
Grace, Nabil ; Jensen, Elin Less -
Corporate Creators:
Lawrence Technological University
Subject/TRT Terms:
[+]
Bridge Decks Concrete Bridges Concrete Bridges--Cracking Concrete Bridges--Floors--Corrosion Corrosion Field Tests Freeze Thaw Tests Laboratory Tests Nondestructive Tests Spalling
Publication/ Report Number:
RC-1567
Resource Type:
Tech Report
Geographical Coverage:
Michigan
Corporate Publisher:
Michigan. Dept. of Transportation. Office of Research and Best Practices
Abstract:
This study developed a procedure to identify concrete bridge decks that are exhibiting the characteristics associated

with falling concrete. Field exploratory work on reinforced concrete bridge decks was supported by analytical and

laboratory investigations. The field work included visual inspection, non-destructive tests, and sampling of full-depth

cores and powder samples from the bottom of the bridge deck. Chief variables assessed were the chance of corrosion

by the half-cell potential, chloride content at the location of the bottom reinforcement, and the concrete pH level. The

chloride diffusivity was estimated from the chloride profile. The laboratory investigation was performed on bridge

deck beams. The beams were constructed from concrete containing chloride levels known to cause corrosion as well as

from a control concrete. Beams were subjected to freeze-thaw or saltwater followed by repeated loading to simulate

field conditions. The following characteristics were quantified: chance of corrosion, corrosion rate, chloride content,

flexural response as a function of environmental exposure and repeated loads, and ultimate strength. The size of the

porous zone around the reinforcement was determined using an environmental scanning electron microscope. Finally, a

strategy was developed to assess if a bridge deck exhibited the characteristics associated with falling concrete. The

strategy included visual inspection of cracking and spalling, assessment of chance of corrosion, chloride content, and

pH levels. If any of these measures exceed critical levels a service life calculation needs to be performed. Based on

existing mathematical models, the time to corrosion initiation and time to corrosion cracking can be predicted. The

resulting time is then compared to the age of the bridge. From this information proper planning for future repair needs

can be made.


Format:
PDF
Funding:
108621
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:8075eeac8aaafe962bef0cb0acadb0d9e20bfb319c837768a70f893659f76674
Download URL:
https://rosap.ntl.bts.gov/view/dot/25379/dot_25379_DS1.pdf
File Type:

Supporting Files

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