Concrete possibilities create 4-VA match

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In the construction trades, engineers and builders are constantly pursuing concrete mixes that provide greater durability and strength. Moreover, concrete adaptations that are biodegradable and nontoxic with reduced greenhouse gas emissions attract even more attention. The potential cherry on top of both would be if the adaptation could result in lower production costs.

Xijin "Emma" Zhang. Photo provided

It was this proposition that brought Xijin "Emma" Zhang, an assistant professor in George Mason University's Department of Civil, Environmental and Infrastructure Engineering, together with Bryan Berger, a professor in University of Virginia's Chemical Engineering Department.

When Zhang, who specializes in fungi-mediated self-healing concrete, found Berger via the National Science Foundation's search tool, she immediately recognized that Berger's extensive experience in producing various biosurfactants from fungi would make him the perfect partner for her 4-VA research team.

Zhang's goal was to test the effect that Superabsorbent Polymers (SAP) would have on concrete. SAPs are hydrophilic polymers used to reduce shrinkage and improve durability. Berger was up for the challenge.

To turn the idea into reality, Zhang developed a proposal for 4-VA funding titled "Multifunctional Fungi-Based Biosurfactants for Durable Concrete Structures." The plan was to do a barrage of experiments injecting a type of biosurfactants known as HFBI, derived from engineered yeast strain, to demonstrate the feasibility of it as a sustainable alternative to conventional air-entraining agents. This research would demand careful study and analysis with particular attention to air content and workability.

Once the proposal was approved, Zhang and Berger assembled a team of students to help deliver the project:

Testing samples. Photo provided

Graduate research assistant Junyi Wang from George Mason was responsible for experiment design, mortar testing (workability, air content, compressive strength), data analysis, and draft manuscript preparation.

PhD in chemical engineering Mack A. Kinkeadefrom Berger's lab at UVA supported biosurfactant extraction and purification.

PhD student Lixin Wang, also from George Mason, assisted with sample testing.

Two civil engineering undergraduates, Phillip Christovaladi Vasilakopoulosand Rafferty Houghton, volunteered their time on the project, gaining critical research experience. Both graduated in May.

"This 4-VA project provided valuable research opportunities for students at multiple levels. Their involvement not only enriched their academic experiences but also helped build a strong pipeline of future researchers," said Zhang.

Following a year of lab work, the team did provetheir hypothesis-HFBI is a sustainable alternative to established air-entraining agents in concrete.

Zhang was then able to share their results with a variety of interested organizations including the American Concrete Institute, Brookhaven National Lab, and the Federal Turner-Fairbank Highway Research Center.

Surface morphology and height cloud map of the three groups of samples under a microscope. The blue-purple coloring on the surface indicates pores. Photo provided

"These presentations at conferences and national labs helped us connect with industry partners and broadened the impact of our work," she said.

Zhang sees the 4-VA experience as a success on many levels, including relationship building.

"The 4-VA@Mason funding was instrumental in launching a meaningful and sustained collaboration with Dr. Berger at UVA," Zhang said. "Since the start of this project, we have co-developed and submitted 3-4 research proposals to National Science Foundation, Department of Energy, and USDA over the past year, some of which were directly inspired by the findings of this 4-VA initiative."