If crushed glass is tough enough for one of the nation’s busiest highways, then it’s good enough for an array of projects, and that ability to turn trash into viable construction materials is one way contractors can lower their costs and increase their competitiveness.
Last summer, roadbuilders in Philadelphia trucked in 2,000 tons of lightweight glass nuggets to accelerate repairs to a collapsed section of Interstate 95. A fuel truck had flipped on its side on an off ramp, sparking a blaze that collapsed the northbound lanes and badly damaged the southbound lanes of that key commercial artery.
Using recycled glass to fill in the collapsed area helped the state to avoid costly supply-chain delays for other materials, Gov. Josh Shapiro said at a news conference as work continued 24/7 behind him. Crews used foam glass aggregate to elevate the underpass area to surface level so it could be paved over, allowing the highway to reopen.
Elizabeth Thompson, vice president for growth marketing at the U.S. Green Building Council, said salvaged materials sometimes can be obtained for free or at a reduced cost, driving down the cost of materials and helping contractors win competitive bids.
Examples include coal-combustion fly ash in concrete; recycled asphalt in pavement; recycled plastic in guardrail offset blocks and flexible delineator posts; and pulverized rubber tires in asphalt pavement and noise walls. Other recycled materials include blast-furnace slag and steel slag, industrial byproducts of iron and steel production.
In addition, researchers are studying whether recycled carpet fibers, ash from municipal solid-waste combustion and roofing shingles can be used effectively in asphalt mixes and other construction materials, according to the Federal Highway Administration.
“The low-hanging fruit is often just salvaging and reusing whatever you can because that can be less expensive,” Thompson said. “It depends on the compressive strength of the concrete that you need and how quickly you need it to cure, but there are waste products that can be incorporated into mixes, and someone might appreciate you taking those materials off their hands.”
On that high-profile I-95 project, the glass material helped to reduce costs associated with transporting construction materials. The nuggets, made from glass bottles and jars diverted from landfills, weigh much less than sand or dirt, so contractors needed many fewer trucks to transport the material to the jobsite, according to the Associated Press. By cutting truck emissions, contractors made the project considerably greener.
Here are four other ways contractors can save money through sustainable construction:
LED LIGHTING SYSTEMS
There are LED systems made for outdoor use, and they typically use about 75% less energy than incandescent lighting systems, according to the Department of Energy. Additionally, LED systems don’t degrade as quickly as incandescent systems and don’t burn out like filament-based systems, according to Monroe Engineering.
Similarly, contractors can reduce costs by switching to hybrid or electric construction equipment from traditional diesel-powered equipment.
RECYCLING MATERIALS
Up to 30% of all building materials transported to a typical construction site end up as waste, which is one reason why debris from construction and demolition accounts for about one-quarter of the country’s waste stream, according the Department of Transportation.
By making a greater effort to recycle materials, contractors can reduce their waste-disposal costs and make projects greener, Thompson said. “Those fees really add up, especially on a large project, so recycling materials is a great way to reduce costs,” she said.
INCREASING WORKFORCE
Sustainable construction practices can help contractors to appeal to younger, environmentally conscious workers who want to feel good about what they’re doing, Thompson said. By expanding the pool of potential hires, contractors can make a dent in the labor shortage, slowing the momentum of wage gains.
Laborers who are more engaged and are working in healthier conditions also will have fewer sick days and are less likely to retire early due to illnesses and injuries, Thompson said. Even simple policies such as not allowing diesel trucks to idle on a jobsite can make a difference in workers’ health and reduce a project’s carbon footprint, she added.
GRANTS AND REBATES
Projects meeting certain sustainability standards may be eligible for tax incentives, grants or rebates from local, state and federal governments. In addition, there are federal programs aimed at upskilling workers in sustainable construction practices, making contractors eligible for a broader range of projects, Thompson said.
“There’s a ton of money going to worker training right now because we recognize that if we don’t have the workforce to make the science actionable, then we won’t actually have a decarbonized world,” she said.
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