“Within the composites’ family, E-CR glass fiber remains the most used fiber type because of its availability and low cost. However, the interest in basalt fibers has been growing since their physical properties exceed those of glass and the cost difference is marginal,” says Alvaro Ruiz Emparanza, director of engineering and business development at Mafic. “In terms of performance, basalt has higher tensile strength and modulus of elasticity than E-CR glass, but its properties are definitely not as high as carbon fiber.” He notes that basalt fiber might be particularly useful in pre-stressed composite structures.
Basalt fiber for rebar is slightly more expensive than glass fiber but significantly cheaper than carbon fiber. With the price of glass going up, however, basalt is becoming more competitive. Emparanza says that the basalt industry doesn’t want to compete against glass and carbon fiber but wants to be part of the total solution that the composites industry can offer.
From Poles to Platforms
Some composites manufacturers are pursuing opportunities in other types of infrastructure where resiliency is of primary concern. “The composites industry is well positioned in terms of structures that can withstand the wind, rain and weather,” says Scott Reeve, president of Creative Composites Group’s, Composite Advantage Division. (Reeve also chairs ACMA’s Transportation Structure Committee.)
In Puerto Rico, the Virgin Islands and Florida, utility companies have been installing GFRP telephone poles, which remain standing in the hurricane winds that bring down wooden poles. West Coast utilities companies have expressed interest in fiberglass-reinforced poles designed to withstand wildfires.
Many utilities are now replacing wooden cross arms on utility poles with composite cross arms. They like the light weight, resilience and non-conductive properties of the composite materials, and the fact that one FRP cross arm can replace two wooden ones.
“We’ve had several projects related to the critical infrastructure for our energy grid. Protective FRP-reinforced composite walls can help prevent transformer damage from high winds, fire, ballistic or blast threats, but are electrically inert so there’s no need to ground them,” says Ohnstad.
Composites are also proving useful in keeping U.S. waterways open and navigable. Reeve says that protective fences (fenders) made from composite materials installed in the water around structures like bridge piers can withstand damage from boats and barges. Because they are non-corrosive, composites are being used more frequently in seawalls as well.
“Another big area is the changeover of rail station platforms from concrete to fiberglass,” Reeve adds. At transit agency stations in the Northeast corridor, the chemicals used for de-icing the train platforms have quickly degraded the concrete. With GFRP platforms, the de-icing chemicals work effectively but cause no damage.
Construction speed is especially important for this application. The platforms are so light that Creative Composites Group can prefabricate large sections and install them at night when the trains aren’t running as frequently as during the daytime. This minimizes train delays and reduces inconvenience to rail passengers.
Some jurisdictions are using composite materials for pedestrian walkways on bridges. “Agencies are putting in bigger, lighter sidewalks on the sides of bridges. Instead of a little two-to-three-foot concrete curb, you may be adding 10-foot-wide sidewalks,” Reeve says.
Obstacles to Adoption
One problem that could slow the adoption of composites for infrastructure work is the method that government owners use to evaluate project bids. “In general, the procurement process is focused on the low bidder on the acquisition side. In the past, the longer life benefits have not been considered, and that’s an area where composite materials excel in terms of corrosion resistance, low maintenance and long life,” says Reeve.
Although some states have begun changing this approach, the Biden administration’s stated commitment to climate change, sustainability and resiliency could speed up the process. “As the administration goes to work, implementing the programs that are going to be used to administer these [infrastructure] dollars, they will be putting that overlay on those programs to achieve maximum benefit in those policy areas,” says Nadeau. He believes that pressure will also come from the public, especially young people who want to see governments and industry adopt more sustainable practices.
If infrastructure owners get serious about reducing carbon emissions “they’re going to see how much more carbon they’re putting into the atmosphere, whenever they specify a steel bridge, or especially a concrete bridge as compared to an FRP bridge,” says Troutman. “We’ve done enough homework to know that our carbon footprint and embodied energy is going to be significantly less than that of aluminum, steel and concrete.”
To get the maximum benefit from infrastructure spending, the composites industry must make a concerted effort to reach out to infrastructure owners, engineers, designers and other decision makers to educate them about the sustainability benefits of composite materials.
“I believe that the major players in the composite industry have not taken this seriously; they have not devoted the level of attention to innovation in this arena like they’ve done for other markets,” says Nanni. “Look at what’s happened with composites in the aviation industry over the course of 30 years, and then look what’s been done in the composite industry for construction. The difference is day and night.”
Part of the problem is that there is no easy way to identify and reach out to the decision makers among building owners and infrastructure agencies. Unlike aerospace, where there are just a few large companies, the key people in building and infrastructure design and construction are spread out among all the states and among various owners/agencies within those states.
Once they connect with the right people, composite manufacturers also need to understand that it will take time for government bureaucracies to make changes, but that their efforts today will pay dividends over time. “In a lot of cases we’re doing presentations to Department of Transportation engineers or to rail agency engineers. And that’s not a sales call. It’s not going to amount to a PO tomorrow. It is part of the educational process on what FRP composites can do,” says Reeve. “They look at this stuff, and they want to vet it and make sure it’s good. And then finally – and it may take years – they say, ‘Hey, this is the right place for me to use FRP composites.’”
The composites industry must continue to impart its important message to infrastructure stakeholders.
“Composites in general have a lot to do toward the sustainability or resilience of our infrastructure,” says Emparanza. “Sadly, we know that climate change is happening, with more severe weather events and the sea level rising. So, we need to act not only for the present but also for the future.”
Mary Lou Jay is a freelance writer based in Timonium, Md. Email comments to email@example.com.