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As per the American Road and Transportation Builders Association, one-third of all bridges require refurbishment or replacement, totaling over 200,000 structures nationwide. A significant factor contributing to the deteriorating state of America’s infrastructure is rebar that has gathered rust, causing cracks which ultimately fragment the surrounding concrete, increasing the likelihood of bridge failures.
Currently, Allium Engineering, established by two MIT PhDs, is extending the lifespan of bridges and other constructions through a novel technology that employs a stainless steel cladding to enhance rebar’s resistance to corrosion. By eradicating corrosion, infrastructure endures significantly longer, necessitating fewer repairs, and leading to a reduction in carbon emissions. The company’s innovation can be seamlessly adapted into existing steel production methods, aiming to make America’s infrastructure more robust, economical, and eco-friendly over the next century.
“Throughout the U.S., the average lifespan of a bridge deck is around 30 years — we’re facilitating lifespans of 100 years,” states Allium co-founder and CEO Steven Jepeal PhD ’21. “There exists an enormous backlog of infrastructure due for replacement, and it has, regrettably, aged more rapidly than anticipated, primarily because the materials we employed were insufficient for the task. We’re striving to harness the momentum of rebuilding America’s infrastructure, but to develop it in a manner that ensures durability.”
To achieve this, Allium applies a thin layer of stainless steel over standard steel rebar, enhancing its resistance to corrosion. Approximately 100,000 pounds of Allium’s stainless steel-clad rebar have already been utilized in construction endeavors across the U.S., and the firm is confident that its method can be swiftly scaled to align with steel mills.
“We incorporate our system into mills so that they don’t need to modify their procedures,” explains Jepeal, who co-founded Allium with Sam McAlpine PhD ’22. “We supply everything necessary to convert a standard product into a stainless-clad option so that any mill can produce a material that resists corrosion. That’s essential for extending the lifespan of global infrastructure.”
Toward superior bridges
Jepeal completed his PhD in the MIT Department of Nuclear Science and Engineering (NSE) under Professor Zach Hartwig. During his tenure, he observed Hartwig and fellow NSE researchers establish Commonwealth Fusion Systems to create the inaugural commercial fusion reactors, which he credits with igniting his passion for startups.
“It certainly fueled my interest in the startup scene,” Jepeal remarks. “MIT is also where I honed my materials science expertise.”
McAlpine obtained his PhD under Associate Professor Michael Short. In 2019, both McAlpine and Short collaborated on an ARPA-E-funded initiative aimed at combining metals to enhance corrosion resistance in extreme environments.
Jepeal and McAlpine resolved to launch a company that would apply a similar method to boost the durability of metals in everyday contexts, engaging with MIT’s Venture Mentoring Service and consulting with Tata Steel, one of the world’s largest steel manufacturers that has worked with the MIT Industrial Liaison Program (ILP). Representatives from Tata informed the founders that one of their most pressing challenges was corrosion of steel.
A fundamental early challenge the founders aimed to tackle was the application of corrosion-resistant materials without significantly increasing costs or disrupting established methods. Traditionally, steelmaking starts with large pieces of precursor steel passing through rollers at extremely high temperatures to extend the material. Jepeal likens this procedure to producing pasta on an industrial scale.
The founders opted to introduce their cladding prior to the rolling phase. Although Allium’s system is tailored, the company currently utilizes existing equipment employed in other metal processing tasks, such as welding, to apply its cladding.
“We enter the mills and handle substantial chunks of steel that are undergoing steelmaking processes but aren’t the final product, and we deposit stainless steel onto the outer layer of their economical carbon steel, which is frequently sourced from recycled materials like vehicles and refrigerators,” Jepeal explains. “The treated steel then follows the mill’s standard production process for creating end products such as rebar.”
Each 40-foot length of thick precursor steel transforms into about a mile of rebar after the rolling process. Rebar enhanced by Allium remains over 95 percent standard rebar and does not require any specific post-processing or handling.
“What emerges from the mill resembles regular rebar,” Jepeal states. “It retains the same strength and can be bent, cut, and installed in all the usual ways. However, instead of having a lifespan of around 30 years in a bridge, it will endure 100 years or more.”
Infrastructure built to endure
Last year, Allium’s facility located in Billerica, Massachusetts, commenced production of its initial commercial cladding material, assisting in the manufacture of approximately 100 tons of the company’s stainless steel-clad rebar in partnership with a collaborating steel mill. That rebar has since been utilized in construction projects in California and Florida.
The company’s first facility has the capability to produce about 1,000 tons of its durable rebar annually, but Allium aspires to establish additional facilities in proximity to its partner steel mills, eventually integrating them into mill operations.
“Our objective of lowering emissions and enhancing this infrastructure motivates us to expand rapidly to fulfill the industry’s demands,” Jepeal states. “Everyone we engage with envisions this being larger than it currently is.”
Allium is also investigating alternative cladding materials and composites. Looking ahead, Jepeal envisions Allium’s technology being applied to other areas beyond rebar, such as train tracks, steel beams, and pipes. However, he emphasizes that the company’s focus on rebar will keep it occupied for the foreseeable future.
“Virtually all of our infrastructure faces this corrosion issue, making it the most significant problem we can address with our skill set,” Jepeal asserts. “Tunnels, bridges, roads, industrial edifices, power stations, chemical facilities — they all contend with this challenge.”
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