In a quiet laboratory in Belgrade, Milica Vlahović and her team at the University of of Belgrade’s Institute of Chemistry, Technology and Metallurgy have uncovered a quiet revolution in building materials—one that could reshape how we think about both construction and waste. Their study, published in *The Holistic Approach to Environment* (in Serbian: *Holistički pristup životnoj sredini*), explores how beechwood biochar, a carbon-rich byproduct of biomass pyrolysis, might replace a portion of sand in mortar mixes. The implications stretch beyond the lab bench, offering a tangible pathway for the energy sector to participate in sustainable construction while addressing the mounting pressures of resource depletion and carbon emissions.
Biochar, traditionally hailed for its soil-enhancing properties in agriculture, is now being eyed for its structural potential. The team tested mortars with biochar contents ranging from 0 to 20 percent by weight, carefully adjusting water content to maintain workability. What they found wasn’t a miracle material—it wasn’t meant to be—but a promising compromise. As biochar content increased, so did porosity, leading to lighter mortars with reduced compressive and flexural strength. Yet, crucially, mortars with up to 10 percent biochar still met the mechanical requirements for non-structural applications, such as interior partitions or insulation coatings.
“It’s not about replacing sand entirely,” says Vlahović. “It’s about finding a balance—where we can use less natural aggregate, reduce the environmental footprint of construction, and give new life to biomass waste that would otherwise go unused.”
The energy sector stands to benefit in multiple ways. Biomass pyrolysis facilities, already producing biochar for soil amendment, could pivot toward supplying a construction-grade material. This diversification could stabilize revenue streams for bioenergy producers facing fluctuating energy markets. Moreover, integrating biochar into mortars aligns with circular economy strategies, turning a low-value byproduct into a co-product with commercial value. For industries under regulatory pressure to cut emissions, this could be a rare win-win: reducing reliance on sand mining (a major ecological disruptor) while sequestering carbon in building materials.
The commercial impact could ripple outward. Construction firms could market lighter, lower-carbon mortars as premium green products. Architects exploring bio-based materials might finally have a viable option for interior applications that doesn’t compromise performance. And for municipalities struggling with biomass waste—think forestry residues or urban green waste—this could offer a scalable solution.
Of course, challenges remain. Scaling production, ensuring consistent biochar quality, and navigating building code approvals will take time. But the study’s lead author is optimistic about the trajectory. “We’re only beginning to explore the potential of biochar in construction,” Vlahović notes. “This isn’t just an academic exercise—it’s a step toward redefining how we build, one brick at a time.”