Materials Science & Engineering

Tiny algae could help fix concrete industry’s dirty little climate secret

Anonymous — Wed, 07 Sep 2022 20:21:15 +0000

Tiny algae could help fix concrete industry’s dirty little climate secret Anonymous (not verified) Wed, 09/07/2022 - 14:21

Concrete is strong, durable, affordable and accessible. But the global concrete industry is responsible for more than 8% of greenhouse gas emissions—more than three times the emissions associated with aviation—and demand is rising. CU engineering expert Wil Srubar shares on The Conversation: four innovative ways to clean up this notoriously hard to decarbonize industry.

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This Carbon-Neutral Cement Is the Future of Infrastructure

Anonymous — Tue, 16 Aug 2022 20:09:36 +0000

This Carbon-Neutral Cement Is the Future of Infrastructure Anonymous (not verified) Tue, 08/16/2022 - 14:09

Popular Mechanics is profiling work by Professor Wil Srubar on a new kind of carbon-neutral cement derived from algae.

Srubar, an associate professor in the Department of Civil, Environmental and Architectural Engineering, is working at the forefront of biomimetic and living materials science and engineering.

Concrete accounts for over seven percent of the world's annual greenhouse gas emissions, and Srubar's algae-based concrete has significant potential to drastically reduce environmental pollution caused by construction activities around the globe.

Read the full article at Popular Mechanics...

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Researchers harness algae to ‘grow’ construction cement

Anonymous — Mon, 18 Jul 2022 14:40:13 +0000

Researchers harness algae to ‘grow’ construction cement Anonymous (not verified) Mon, 07/18/2022 - 08:40

The Associated Press is spotlighting work by Wil Srubar on algae-based concrete.

Srubar, an associate professor in the Department of Civil, Environmental and Architectural Engineering, is working at the forefront of biomimetic and living materials science and engineering.

He views the algae-based concrete as having significant potential to drastically reduce environmental pollution caused by construction activities around the globe.

Read the full article at the Associated Press...

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Denver Post highlights Srubar's green concrete research

Anonymous — Tue, 12 Jul 2022 19:56:09 +0000

Denver Post highlights Srubar's green concrete research Anonymous (not verified) Tue, 07/12/2022 - 13:56

The Denver Post has published an article showcasing work by Wil Srubar on algae-based concrete.

Srubar, an associate professor in the Department of Civil, Environmental and Architectural Engineering, is working at the forefront of biomimetic and living materials science and engineering.

He views the algae-based concrete as having significant potential to drastically reduce environmental pollution caused by construction activities around the globe.

Read the full article at the Denver Post...

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Interesting Engineering highlights Srubar's algae-based concrete

Anonymous — Wed, 29 Jun 2022 15:33:28 +0000

Interesting Engineering highlights Srubar's algae-based concrete Anonymous (not verified) Wed, 06/29/2022 - 09:33

Interesting Engineering has published an article highlighting research led by Wil Srubar into the development of a groundbreaking biologically-grown concrete that could significantly reduce carbon emissions.

Srubar, an associate professor in the Department of Civil, Environmental and Architectural Engineering, is working at the forefront of biomimetic and living materials science and engineering.

He views the algae-based concrete as having significant potential to drastically reduce environmental pollution caused by construction activities around the globe.

The Interesting Engineering piece discusses the creation of the biologically engineered material and how it could change the future of construction.

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Cities of the future may be built with algae-grown limestone

Anonymous — Mon, 27 Jun 2022 14:59:30 +0000

Cities of the future may be built with algae-grown limestone Anonymous (not verified) Mon, 06/27/2022 - 08:59

Global cement production accounts for 7% of annual greenhouse gas emissions in large part through the burning of quarried limestone. Now, a CU �鶹ӰԺ-led research team has figured out a way to make cement production carbon neutral—and even carbon negative—by pulling carbon dioxide out of the air with the help of microalgae.

The CU �鶹ӰԺ engineers and their colleagues at the Algal Resources Collection at the University of North Carolina Wilmington (UNCW) and the National Renewable Energy Laboratory (NREL) have been rewarded for their innovative work with a $3.2 million grant from the U.S. Department of Energy’s (DOE) Advanced Research Projects Agency–Energy (ARPA-E). The research team was recently selected by the HESTIA program (Harnessing Emissions into Structures Taking Inputs from the Atmosphere) to develop and scale up the manufacture of biogenic limestone-based portland cement and help build a zero-carbon future.

“This is a really exciting moment for our team,” said Wil Srubar, lead principal investigator on the project and associate professor in Civil, Environmental and Architectural Engineering and CU �鶹ӰԺ’s Materials Science and Engineering Program. “For the industry, now is the time to solve this very wicked problem. We believe that we have one of the best solutions, if not the best solution, for the cement and concrete industry to address its carbon problem.”

Concrete is one of the most ubiquitous materials on the planet, a staple of construction around the world. It starts as a mixture of water and portland cement, which forms a paste to which materials such as sand, gravel or crushed stone are added. The paste binds the aggregates together, and the mixture hardens into concrete.

To make portland cement, the most common type of cement, limestone is extracted from large quarries and burned at high temperatures, releasing large amounts of carbon dioxide. The research team found that replacing quarried limestone with biologically grown limestone, a natural process that some species of calcareous microalgae complete through photosynthesis (just like growing coral reefs), creates a net carbon neutral way to make portland cement. In short, the carbon dioxide released into the atmosphere equals what the microalgae already captured.

Ground limestone is also often used as a filler material in portland cement, typically replacing 15% of the mixture. By using biogenic limestone instead of quarried limestone as the filler, portland cement could become not only net neutral but also carbon negative by pulling carbon dioxide out of the atmosphere and storing it permanently in concrete.

If all cement-based construction around the world was replaced with biogenic limestone cement, each year, a whopping 2 gigatons of carbon dioxide would no longer be pumped into the atmosphere and more than 250 million additional tons of carbon dioxide would be pulled out of the atmosphere and stored in these materials.

This could theoretically happen overnight, as biogenic limestone can “plug and play” with modern cement production processes, said Srubar.

“We see a world in which using concrete as we know it is a mechanism to heal the planet,” said Srubar. “We have the tools and the technology to do this today.”

A scanning electron micrograph of a single coccolithophore cell, Emiliania huxleyi. (Credit: Wikimedia Commons / Alison R. Taylor, University of North Carolina Wilmington Microscopy Facility)

The coccolithophore has been part of the Black Sea ecology for millennia, and in the summer these calcite-shedding phytoplankton can color much of the Black Sea cyan. (Credit: NASA Goddard Space Flight Center, Flickr)

Limestone in real time

Srubar, who leads the Living Materials Laboratory at CU �鶹ӰԺ, received a National Science Foundation CAREER award in 2020 to explore how to grow limestone particles using microalgae to produce concrete with positive environmental benefits. The idea came to him while snorkeling on his honeymoon in Thailand in 2017.

He saw firsthand in coral reefs how nature grows its own durable, long-lasting structures from calcium carbonate, a main component of limestone. “If nature can grow limestone, why can’t we?” he thought.

“There was a lot of clarity in what I had to pursue at that moment. And everything I've done since then has really been building up to this,” said Srubar. He and his team began to cultivate coccolithophores, cloudy white microalgae that sequester and store carbon dioxide in mineral form through photosynthesis. The only difference between limestone and what these organisms create in real time is a few million years.

With only sunlight, seawater and dissolved carbon dioxide, these tiny organisms produce the largest amounts of new calcium carbonate on the planet and at a faster pace than coral reefs. Coccolithophore blooms in the world’s oceans are so big, they can be seen from space.

“On the surface, they create these very intricate, beautiful calcium carbonate shells. It's basically an armor of limestone that surrounds the cells,” said Srubar.

Students working in the Living Materials Laboratory, which utilizes calcifying microalgae to produce limestone and create a carbon neutral cement, as well as cement products which can slowly pull carbon dioxide out of the atmosphere and store it. (Credit: Glenn Asakawa/CU �鶹ӰԺ)

Commercializing coccolithophores

These microalgae are hardy little creatures, living in both warm and cold, salt and fresh waters around the world, making them great candidates for cultivation almost anywhere—in cities, on land, or at sea. According to the team’s estimates, only 1 to 2 million acres of open ponds would be required to produce all of the cement that the U.S. needs—0.5% of all land area in the U.S. and only 1% of the land used to grow corn.

And limestone isn’t the only product microalgae can create: microalgae’s lipids, proteins, sugars and carbohydrates can be used to produce biofuels, food and cosmetics, meaning these microalgae could also be a source of other, more expensive co-products—helping to offset the costs of limestone production.

To create these co-products from algal biomass and to scale up limestone production as quickly as possible, the Algal Resources Collection at UNCW is assisting with strain selection and growth optimization of the microalgae. NREL is providing state-of-the art molecular and analytical tools for conducting biochemical conversion of algal biomass to biofuels and bio-based products.

There are companies interested in buying these materials, and the limestone is already available in limited quantities.

Minus Materials, Inc., a CU startup founded in 2021 and the team’s commercialization partner, is propelling the team’s research into the commercial space with financial support from investors and corporate partnerships, according to Srubar, a co-founder and acting CEO. Minus Materials previously won the university-wide Lab Venture Challenge pitch competition and secured $125,000 in seed funding for the enterprise.

The current pace of global construction is staggering, on track to build a new New York City every month for the next 40 years. To Srubar, this global growth is not just an opportunity to convert buildings into carbon sinks but to clean up the construction industry. He hopes that replacing quarried limestone with a homegrown version can also improve air quality, reduce environmental damage and increase equitable access to building materials around the world.

“We make more concrete than any other material on the planet, and that means it touches everybody's life,” said Srubar. “It's really important for us to remember that this material must be affordable and easy to produce, and the benefits must be shared on a global scale.”

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Hubler earns NSF CAREER award to advance living building materials

Anonymous — Tue, 22 Mar 2022 15:38:17 +0000

Hubler earns NSF CAREER award to advance living building materials Anonymous (not verified) Tue, 03/22/2022 - 09:38

Assistant Professor Mija Hubler is a recipient of a three year, $548,000 National Science Foundation (NSF) Faculty Early Career Development (CAREER) award for her proposal “Mechanical Modeling of Living Building Materials for Structural Applications.”

Major advances are being made in the study of living building materials that can be grown in the laboratory and could replace concrete, a significant driver of CO2 emissions in the construction industry

“This research is about creating a mechanical model for living building material,” Hubler said. “The model will enable the design of structures and the engineering of living building material to achieve the desired performance needed for structural applications.”

NSF CAREER awards support early career faculty who are dedicated to research and education. Hubler is using this project to integrate her education and research goals through the study of mechanics in civil infrastructure materials, as well as to improve the recruitment and retention of female and non-traditional students in research and innovation career tracks.

“These activities can help meet a growing workforce demand and support cross-disciplinary innovation for infrastructure materials,” Hubler said. “I hope to grow interest in research careers from a broad audience in this area in part by working with Colorado Mesa University to engage students there in working with living building materials.”

Hubler said that using living building materials for structural applications will help replace concrete as the main building material used in construction today.

“Living building material does not require cement, which is the binding ingredient of concrete that drives its large carbon footprint,” Hubler said. “It is much more crack resistant than concrete and enables material recycling.”

Alternatives to concrete are of interest to civil engineers and the construction industry to address both building durability concerns and CO2 impact. Although past new construction materials have been rejected due to lacking the mechanical properties and behavior of traditional materials, Hubler said living building materials show major promise.

“I have been inspired to better understand what features of the material control the mechanics to engineer new materials to better meet expectations, and also to develop mechanical models of new construction materials to enable them to be adopted into design practices,” Hubler said.

Hubler believes that the model her group will develop will also be applicable to other novel materials, including reinforced metal foams and stabilized soils. She anticipates developing a practical model for living building materials within the next two years, with a five-year goal of using the model to design a full-scale beam composed of living material.

Hubler is a faculty member at the Department of Civil, Environmental and Architectural Engineering and the Materials Science and Engineering Program and serves as the Co-Director of the Center for Infrastructure, Energy and Space Testing.

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Dr. Wil Srubar: Concrete has a colossal carbon footprint and we can help fix that in Colorado

Anonymous — Thu, 17 Feb 2022 23:10:19 +0000

Dr. Wil Srubar: Concrete has a colossal carbon footprint and we can help fix that in Colorado Anonymous (not verified) Thu, 02/17/2022 - 16:10

Wil Srubar has written a column for the �鶹ӰԺ Daily Camera discussing the importance of an often overlooked item in fighting climate change: concrete.

An associate professor in the Department of Civil, Environmental and Architectural Engineering, Srubar is conducting groundbreaking research on alternatives to the most widely used building material on Earth.

"If Colorado truly envisions itself to be a bold leader on tackling climate change, our state must have a strategy for decarbonizing concrete. Although concrete is not always top of mind, this critical building block presents a wealth of opportunities for sustainability and business innovation — as well as reducing harmful emissions.

"This critical material is the literal foundation of our society; after water, it’s the most widely used substance on Earth. But the production of concrete’s key ingredient, Portland cement (a generic term, not a brand name), generates a staggering 7% of the world’s heat-trapping carbon dioxide — triple the emissions of civil aviation..."

Read the full column in The Daily Camera...

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Discover Magazine highlights CU �鶹ӰԺ research on bacteria as a key to concrete alternatives

Anonymous — Mon, 29 Nov 2021 18:21:03 +0000

Discover Magazine highlights CU �鶹ӰԺ research on bacteria as a key to concrete alternatives Anonymous (not verified) Mon, 11/29/2021 - 11:21

Scientists are turning to the living world to find alternatives for concrete. Many different animals, such as tortoises, turtles and oysters, produce hardened structural materials of their own — but one of the most interesting sources of hard materials comes from certain bacteria that produce calcite, a form of calcium carbonate that makes up limestone.

Concrete is the most widely consumed material on Earth, with about 25 billion tons produced every year. It lasts decades longer than other building materials and it doesn’t burn, rust or rot. But the manufacturing of cement, the primary component of concrete, is the most energy intensive of all manufacturing industries; it’s a major source of carbon dioxide emissions, amounting to 2.8 billion tons per year or roughly 8 percent of global carbon dioxide emissions.

As we stare down the catastrophic changes occurring to the Earth’s climate, we must now reckon with the associated environmental costs of producing concrete. Living construction materials such as calcite-producing bacteria, which require little energy and have substantially lower carbon footprints, could prove useful for a variety of functions.

On the Mend

The bacteria can be used to repair cracks in concrete, for example. Concrete has low tensile strength and is inherently brittle, which makes it susceptible to cracking. Traditional repair methods use chemicals such as epoxy systems that are expensive and require hands-on work. But dispersions of a bacteria called Bacillus halodurans, genetically modified by scientists to enhance its calcite-producing qualities, can be sprayed into the cracks instead.

Scanning technology showed in 2019 that the calcite produced by the bacteria penetrates the entire crack depth to form a permanent seal. A liquid repair system based on this technology has recently appeared on the market.

A more ambitious use of calcite-producing bacteria is in the manufacture of concrete that heals itself. Dutch scientists encapsulated Bacillus bacteria, which can survive for decades without food or water, in biodegradable plastic with calcium lactate as a food source. These capsules were then added to a concrete mix. When a crack appeared in the concrete, rainwater entered and dissolved the plastic, allowing the bacteria to metabolize and produce healing calcite.

“It is combining nature with construction materials,” says inventor Henk Jonkers, a researcher at the Delft University of Technology in the Netherlands. “Nature is supplying us a lot of functionality for free — in this case limestone-producing bacteria. If we can implement it in materials, we can really benefit from it, so I think it’s a really nice example of tying nature and the built environment into one new concept.”

Growing Up

Perhaps the most interesting application of calcite-producing bacteria comes from the work of scientists at the �鶹ӰԺ, who last year used bacteria to manufacture a building block that contains no cement at all. They made the low-carbon construction material by pouring a mixture of sand, gelatin, calcium nutrients and a photosynthetic cyanobacterium into a mold. When the gelatin set, it formed a scaffold that supported bacterial growth. The bacteria then deposit calcium carbonate, turning the mixture into a solid block that’s roughly as strong as a cement-based block.

There’s one key difference, however. Traditional cement-like materials gain their strength very slowly; strength is typically measured only after 28 days. By comparison, blocks made by the bacterial method obtain their full strength after just seven days.

It might be possible to use this method to “grow” structural materials in remote places and hostile environments. Relatively little material is needed and sacks of the constituents could be distributed in a dehydrated form. Such a system might be useful for temporary civil and military structures, paving, facades or other light-duty, load-bearing structures.

The material must be dried out to reach its maximum strength, but there could also be advantages to keeping the blocks wet enough that the bacteria perform other useful functions. This multifunctional building material could be capable, for example, of reversing structural damage in the event of an earthquake. Other functions may be possible too: sensing and responding to toxins in the air or even glowing in the dark.

“We already use biological materials in our buildings, like wood, but those materials are no longer alive,” says Wil Srubar, an assistant professor of engineering at the �鶹ӰԺ who was involved in the research. “We’re asking, ‘Why can’t we keep them alive and have that biology do something beneficial too?’”

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The value of core facilities from a researcher’s perspective

Anonymous — Fri, 19 Nov 2021 18:44:50 +0000

The value of core facilities from a researcher’s perspective Anonymous (not verified) Fri, 11/19/2021 - 11:44

ov. 18, 2021 • By Rachel Leuthauser

Ahead of the joint Materials Instrumentation and Multimodal Imaging Core (MIMIC) Facility and Colorado Shared Instrumentation in Nanofabrication and Characterization (COSINC) facility virtual webinar on Nov. 18, Associate Professor Wil Srubar shares the importance of having core facilities at public institutions.

The value of having access to state-of-the-art equipment and expert staff cannot be overstated when working towards groundbreaking research. The centralization at core facilities can be key to improving research efficiency.

The amount of research happening at the technology-based labs housed in the Research & Innovation Office is proof of that. There are 23 core facilities in all, including the Materials Instrumentation and Multimodel Imaging Core (MIMIC) facility.

Above: Wil Srubar
Header image: Renishaw InVia - Raman Microscope used in Combined Raman and Nanoindentation system.

The MIMIC facility contains equipment that allows researchers to view materials down to the submicron scale. Wil Srubar, one of the faculty members behind MIMIC – along with Principal Investigator Virginia Ferguson – emphasized the unique suite of characterization instruments at the facility.

“The high-resolution, 4D X-ray microscope and the coupled Raman-nanoindentation system are especially unique,” said Srubar, an associate professor of civil and architectural engineering and materials science. “Very few exist along the Front Range, so we are very lucky to have these exceptional resources right here at the �鶹ӰԺ.”

Srubar is just one of the faculty members using the equipment in the MIMIC facility. MIMIC is open to researchers in academic, industrial and individual fields.

“Core facilities like MIMIC enable instrument access to multiple researchers on campus,” Srubar said. “This is important because the instruments get much more usage if multiple faculty members, postdocs and student researchers have access to them. Shared facilities enable CU �鶹ӰԺ to maximize the resources on campus.”

Srubar and his colleagues have explored a number of projects using the instruments in the MIMIC facility. He said in one study published in Scientific Reports, a Nature publication, his team used the Raman-nanoindentation system to show that engineered microorganisms can tailor the nanomechanical properties of precipitated calcium carbonate.

In other words, Srubar was able to turn microbes into architects of tiny crystals by manipulating their genes. His team genetically programmed E. coli to create limestone particles. The Raman-nanoindentation system helped the team not only view the materials, but also deliver the mechanical and chemical characteristics of the material.

Inside the Hysitron TI 950 TriboIndenter used in the Combined Raman and Nanoindentation system.

Srubar’s research in the MIMIC facility has also focused on finding sustainable and durable construction methods to reduce ts carbon footprint.

“We have extensively used the 4D X-ray microscope to characterize the porosity of new conventional and alternative cement pasts,” Srubar said. “Porosity is an important parameter that affects the long-term durability of new concrete materials.”

Srubar’s hope is to decarbonize the construction industry by developing biomimetic and bioengineered materials that store carbon for millennia. He explained that currently, more than 11% of global carbon dioxide emissions are due to manufacturing building materials.

“We believe new material technologies, such as the ones we are studying in my lab and characterizing using instruments from the MIMIC facility, will accelerate the transformation of our building environment into massive carbon sinks,” Srubar said. “The MIMIC facility is enabling us to make groundbreaking advances toward that goal.”

The Materials Instrumentation and Multimodal Imaging Core (MIMIC) facility and the Colorado Shared Instrumentation in Nanofabrication and Characterization (COSINC) facility will host a joint virtual webinar from noon to 2 p.m. on Nov. 18 via Zoom. Registration before the event is required through this link.

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