Details:

Creators:
Trejo, David ; Gardoni, Paolo ; Kim, Jeong Joo ; Zidek, Jason
Trejo, David ; Gardoni, Paolo ; Kim, Jeong Joo ; Zidek, Jason Less -
Corporate Creators:
Texas Transportation Institute
Corporate Contributors:
Texas. Dept. of Transportation. Research and Technology Implementation Office
Subject/TRT Terms:
[+]
Fiber-reinforced Concrete--Evaluation Fiber Reinforced Concrete Glass-reinforced Plastics--Evaluation Glass Fiber Reinforced Plastics Reinforcing Bars Reinforcing Bars--Evaluation.
Publication/ Report Number:
FHWA/TX-09/0-6069-1
Resource Type:
Tech Report
Geographical Coverage:
Texas
Edition:
Technical report; Sept. 2007-Aug. 2008.
Corporate Publisher:
Texas Transportation Institute
Abstract:
Significant research has been performed on glass fiber-reinforced polymer (GFRP) concrete reinforcement.

This research has shown that GFRP reinforcement exhibits high strengths, is lightweight, can decrease time of

construction, and is corrosion resistant. Regarding the corrosion resistance, research has shown that the chemical

reactions that occur in GFRP bars do not result in expansive products—products that can damage the concrete

surrounding the reinforcement. Although not classical steel corrosion, much research that has been performed

shows that GFRP reinforcing bars do corrode, reducing the tensile capacity of the GFRP reinforcing bars as a

function of time. The American Concrete Institute (ACI) recognized this and places a reduction factor on the

allowable design strength of GFRP reinforcing bars. A drawback of the majority of the research is that GFRP

reinforcing bars have typically been directly exposed to aggressive solutions, exposure conditions possibly not

similar to the exposure they would encounter while embedded in concrete. Limited research has been performed

evaluating the tensile capacity reduction of bars embedded in concrete; however, these bars were only exposed for

relatively short durations.

This research investigated the characteristics of GFRP reinforcing bars embedded in concrete for 7 years and

exposed to a mean annual temperature of 69 oF (23 oC) and an average precipitation of 39.7 inches (1008 mm),

fairly evenly distributed throughout the year. Three manufacturers provided #5 and #6 bars for this research.

Results indicate that GFRP reinforcing bars do exhibit reduced capacities when embedded in concrete. A model

was developed to assess the tensile capacity of bars embedded in concrete. The model was based on a general

diffusion model, where diffusion of water or ions penetrate the bar matrix and degrade the glass fibers. The model

is dependent on time, diffusion characteristics of the matrix material, and the radius of the GFRP reinforcing bar.

The model indicates that GFRP reinforcement bars with larger diameters exhibit lower rates of capacity loss.

However, the times required for the tensile capacity of the GFRP bars to drop below the ACI design requirements

for #3, #5, and #6 bars were less than 6 years. Further research is needed to determine how this will affect the

design of GFRP-reinforced concrete structures; however, consideration of changing the ACI design requirement

may be warranted.


Format:
PDF
Funding:
Project 0-6069
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:279072f753d033afcb6c143eb1e69474081d516f5c711627e4807c2f0299a6b0
Download URL:
https://rosap.ntl.bts.gov/view/dot/17628/dot_17628_DS1.pdf
File Type:

Supporting Files

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