Details:

Creators:
Boisvert, Denis M.
Corporate Creators:
New Hampshire. Dept. of Transportation
Corporate Contributors:
United States. Federal Highway Administration
Subject/TRT Terms:
[+]
Bridge Approaches Bridge Decks Bridges--Floors Concrete Bridges Concrete Bridges--Corrosion Concrete Slabs Corrosion Resistant Materials Fiber Reinforced Concrete Field Tests Freeze Thaw Tests Laboratory Tests Reinforcing Steel Slabs
Publication/ Report Number:
FHWA-NH-RD-13733H
Resource Type:
Tech Report
Geographical Coverage:
New Hampshire
Corporate Publisher:
New Hampshire Department of Transportation
Abstract:
The upper mat of reinforcing steel, in exposed concrete bridge approach slabs, is prone to corrosion damage. Chlorides applied to the highways

for winter maintenance can penetrate this concrete layer. Eventually chlorides reach the steel and begin the corrosion process.

The objective of this research project was to investigate the performance of approach slabs constructed with structural fibers to replace the top

mat of reinforcing steel. The research studied whether the performance of approach slabs reinforced with structural fibers would be equivalent

to traditionally reinforced approach slabs.

NHDOT Materials & Research Bureau technicians performed standard quality acceptance tests on the fresh concrete at the time of placement.

Technicians also fabricated three freeze/thaw prisms for each mix. The specimens survived freeze/thaw testing with only minor physical

deterioration, consisting of slight scaling and pitting. The Civil Engineering Department of the University of New Hampshire (UNH) was

contracted to perform laboratory testing. The beam samples were tested for First Crack Strength and Average Residual Strength in accordance

with ASTM C 1018 and C 1399, respectively. An independent testing laboratory extracted two cores from each approach slab to evaluate the

air matrix within the concrete. Comparisons of the laboratory test results show that compressive and flexural strengths are similar for both

mixes. The plots resulting from the residual strength testing show that the fiber-mix had greater strength after cracking than the normal mix.

Periodic visual observations of the approach slabs were made to evaluate field performance by comparing crack size, frequency and scaling.

After more than three and half years in service, the two approach slabs have performed similarly and well. The expected advantages of a thicker

concrete cover over steel reinforcement will not be seen for many years. The epoxy-coated steel in the conventional slab construction should

also delay damage from corrosion.

Based on the performance observations to date, fiber-reinforced concrete is recommended for use in this and other applications where delaying

the effects of steel corrosion is of interest. The NHDOT has implemented the use of fiber-reinforced concrete for all approach slabs as a result

of this study.


Format:
PDF
Funding:
13733H, X-A000(153)
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:370f62662b89caafc05a145a69e72b236bab8e0eab3eaaef5b79b06dbff1850b
Download URL:
https://rosap.ntl.bts.gov/view/dot/25749/dot_25749_DS1.pdf
File Type:

Supporting Files

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