Understanding Material Durability

Workshop Examines Aging of Composite Materials

The Exploratory Advanced Research Program Fact Sheet: Scanning and Convening Activities

Discussing Composite Materials

The 2-day International Workshop on Aging of 

Composites was held September 25–26, 2013, at 

the National Transportation Safety Board Training 

Center in Ashburn, VA. Thirty-five leading researchers, 

designers, and owners of infrastructure systems 

with advanced fiber reinforced polymer (FRP) 

composite materials, including eight participants 

from the international community, met to discuss 

and summarize the state of the knowledgebase on 

the aging behavior of FRPs. Workshop participants 

discussed FRP material and component resistance 

factors based on available data, suggested effective 

methods to collect additional data, and identified 

procedures to refine and integrate information. 

Participants also sought to identify research needs 

for future research, development, and evaluation 

programs dealing with durability and design issues. It 

is hoped identifying these needs will lead to realistic 

design, construction, evaluation, and rehabilitation 

guidelines. 

Fiber Reinforced Materials

For over 30 years, FRPs have been gradually 

accepted as advanced and durable materials for 

infrastructural applications. FRPs have been used 

in structures for highways, railways, waterways, 

utility poles, wind-turbine blades, and pipelines. 

Hundreds of pedestrian and vehicular bridges 

have been built worldwide using FRP composite 

materials. To better understand and accurately 

determine how durable these composite materials 

are, and how they will degrade, accelerated aging 

tests on composites can be conducted under 

controlled laboratory conditions. Data from these 

tests can then be correlated with the field data 

from in-service FRP composite bridges and other 

infrastructure systems. 

Focused Discussion

During the workshop, over 20 presentations examined 

topics including critical areas of durability, available 

aging data, durability assessment methods, and 

durability design. Each presentation concluded by 

looking at areas in need of further research. Workshop 

participants were then divided into four working 

groups for focused brainstorming discussions. Each 

group discussed and examined a specific topic, 

including internal and external reinforcements; 

shapes; test methods; and material degradation and 

life prediction models. The workshop presenters then 

asked each group to come to an understanding of 

the currently available research for its topic, identify 

specific issues that are hindering implementation, 

consider current research gaps and funding sources, 

and identify which research projects would have the 

most immediate impact. The research needs from 

all groups were then integrated and prioritized in 

terms of their importance and impact on composites 

infrastructure.

CORROSION DECAY is an expensive and ongoing challenge throughout the 

U.S.-highway network. To mitigate this problem, advanced composite materials 

are used in a wide range of infrastructure applications. These materials are 

lightweight, high strength and offer high-fatigue and corrosion resistant 

properties; however, accurately understanding how these materials degrade and 

age over time is critical for safe and economical implementation. Accordingly, 

a workshop supported by the Federal Highway Administration’s Exploratory 

Advanced Research (EAR) Program and the National Science Foundation was 

held to discuss state-of-the-art understanding and future research directions on 

aspects of aging of composites.
Group Recommendations

Workshop participants identified four overall research 

topics that were considered to be high priority. The 

first topic area was “Mechanisms of Deterioration.” 

Participants suggested research should focus on 

reductions in strength, stiffness, and durability at micro, 

meso, and macro levels. It was noted a multiscale 

approach is needed for characterizing and developing 

a better understanding of the mechanisms of bond and 

bond degradation caused by moisture. Participants 

also suggested a focus on interface characterization, 

moisture effects, and static and cyclic fatigue. 

 The next research topic was “Test Methods and 

Modeling.” It was noted that aging data should be 

collected from structures in the field and combined 

with laboratory accelerated aging test data to develop 

predictive models. Participants also suggested there 

should be standardization of basic durability and 

fire test methods. Another research priority was 

“Investigation of Synergistic Effects on Long-Term 

Performance.” Here, participants recommended further 

research into temperature and moisture, as well as 

static and fatigue loads. Additional focus areas included 

researching interactions between stress, temperature, 

and chemicals. The manufacturing process was also 

identified for further research to better understand 

the constituent materials and effect on long-term 

performance. 

 Participants suggested the final priority research 

topic should be “Correlation of Short-Term and LongTerm Performance.” Participants highlighted it is 

important to relate short-term durability in laboratory 

tests to long-term performance in the field. They 

suggested the development of simple and accurate 

techniques for field monitoring and inspection and 

evaluation guidelines. Finally, it was recommended 

that a searchable knowledge database should be 

developed to cover laboratory and field tests and 

experimental results.

Future Research

It was widely agreed that the workshop accomplished 

its goal to further understanding of aging of composites, 

assess state of the art, and consider research and 

development needs for future studies. Workshop 

participants agreed that it is time to evaluate the 

performance of FRP structures by collecting field 

samples and testing for property degradation. It was 

noted that accelerated aging data and predictive 

models will lead to accurate life-cycle assessment 

of FRPs. Additionally, it was suggested FRP 

composites have great potential as a sustainable 

material with a high strength-to-weight ratio to 

design durable, efficient, and safer infrastructure 

systems.

 It is anticipated that, equipped with the future 

research directions identified in this workshop, 

the larger community interested in research 

and development for highway transportation 

FRP applications could ultimately develop an 

interdisciplinary research program.

Learn More

For more information on the EAR Program and FRP 

composite materials, contact Lou Triandafilou at 

202-493-3059 or visit www.statler.wvu.edu/cfc/

research/projects/aging.php.

Understanding Material Durability

Workshop Examines Aging of Composite Materials

What Is the Exploratory Advanced 

Research Program?

FHWA’s Exploratory Advanced Research 

(EAR) Program focuses on long-term, highrisk research with a high payoff potential. 

The program addresses underlying gaps 

faced by applied highway research 

programs, anticipates emerging issues with 

national implications, and reflects broad 

transportation industry goals and objectives. 

 To learn more about the EAR Program, 

visit the Exploratory Advanced Research 

Web site at www.fhwa.dot.gov/advancedresearch. The site features information on 

research solicitations, updates on ongoing 

research, links to published materials, 

summaries of past EAR Program events, and 

details on upcoming events. For additional 

information, contact David Kuehn at FHWA, 

202-493-3414 (email: david.kuehn@dot.gov), 

or Terry Halkyard at FHWA, 202-493-3467 

(email: terry.halkyard@dot.gov). 

Publication No.

FHWA-HRT-14-068

HRTM-30/06-14(WEB)E

Photo caption, front page: Mr. 

David Kuehn addresses questions 

from the audience on the morning 

of September 26, 2013