A new study introduces a cement-based material that is lightweight, low-carbon, and exceptionally tough—drawing inspiration from nature’s porous structures.
Study: Nature-inspired hierarchical building materials with low CO2 emission and superior performance. Image Credit: Nature Peaceful/Shutterstock.com
Published in Nature Communications, the study presents LLST (low-carbon, lightweight, strong, and tough), a novel cement-based material that combines reduced environmental impact with impressive mechanical performance. The researchers developed LLST by rapidly forming a hydrogel skeleton, followed by the deposition of cement hydrates that act as a structural "skin," mimicking natural porous systems.
Background
Lightweight, high-performance cement materials are gaining attention as a promising strategy for cutting CO2 emissions across the construction sector. By reducing cement usage, lowering energy demands in production and transport, and extending the service life of structures, such materials could significantly curb the environmental footprint of cement.
The challenge, however, lies in maintaining strength and toughness—qualities often compromised in lightweight formulations. Nature, on the other hand, offers elegant solutions. Structures like bone, coral, and honeycomb achieve a balance of low weight and high resilience through finely tuned hierarchical porosity. These systems efficiently manage mechanical stress and absorb energy, making them ideal templates for material design.
Yet, despite this biological inspiration, previous research has rarely explored precise control over nano- and micro-scale pore structures in cement-based materials. This study addresses that gap by introducing LLST, which integrates micropores (1–50 μm) and nanopores (5–100 nm) into a carefully engineered framework.
To investigate the impact of pore architecture and cement dosage, researchers tested four LLST formulations with cement contents ranging from 20% to 80%. Each mix included a hydrogel structure and crosslinking agent, while a pure cement sample served as a baseline reference.
The team cast cubic and cuboidal samples, curing them for 28 days before analyzing their internal structures and mechanical properties. They used scanning electron microscopy (SEM) to observe microstructures and Fourier-transform infrared (FTIR) spectroscopy to assess chemical groups.
To understand pore distribution, they applied X-ray computed tomography (X-CT), mercury intrusion porosimetry, and proton nuclear magnetic resonance (¹H NMR) spectroscopy. Additionally, X-ray diffraction helped evaluate mineral phases at 7 and 28 days of curing.
Beyond physical testing, the researchers conducted molecular dynamics simulations using a machine learning force field. These simulations, powered by ab initio molecular dynamics (AIMD) and well-tempered metadynamics, were carried out in the LAMMPS code to explore interactions at the atomic level.
Results and Discussion
In the LLST with 10 % cement content, a sponge-like hydrogel skeleton with a smooth surface formed within just 10 minutes. Cement particles adhered to this framework, guided by hydrogen bonding, van der Waals forces, and ionic interactions. Over time, this configuration remained stable, with cement hydration proceeding along the hydrogel template—a process still evident after seven days.
By the 28-day mark, cement hydrates had partially filled the hydrogel's micropores, introducing nanopores and creating a hierarchical nano/micro-porous structure. This dual-scale network was consistent across all LLST mixes, resulting from the initial gelation and subsequent hydrate deposition.
Compared to reference samples, which had irregular, sharp-edged pores that concentrated stress, LLST exhibited a uniform, sponge-like network that allowed stress to distribute evenly—enhancing its ability to withstand mechanical loads.
X-CT scans confirmed the dominance of micropores (1–50 μm) in LLST, in contrast to the much larger macropores (0.5–2.0 mm) typical of foam cement. Some larger pores (above 50 μm) were observed in LLST, likely due to air bubbles introduced during the 10-minute mixing process. This suggests room for improvement in refining the mixing technique to better control pore size.
On the mechanical side, LLST showed significant improvements. Flexural strength increased by 30 % to 220 % compared to the reference material. Toughness, measured through midspan deformation rate and fracture energy, rose by 91 %–687 % and 102 %–1365 %, respectively. These enhancements are directly tied to the multi-scale porous structure, which improves stress absorption and crack resistance.
Conclusion
This study showcases how bio-inspired design can lead to more sustainable and robust construction materials. By replicating the hierarchical porosity found in natural systems, LLST achieves a rare combination of low weight, reduced emissions, and mechanical resilience.
Compared to conventional cement paste, LLST demonstrated a 54 % reduction in density and 49 % lower carbon emissions—while improving specific compressive strength by 145 % and fracture energy by 1365 %. These performance gains are attributed to the material’s multi-scale stress distribution and strong chemical bonding, confirmed both experimentally and through simulations.
Molecular dynamics modeling revealed that calcium ions in the cement formed strong bonds with carboxyl groups in the hydrogel—a key interaction underpinning the material’s durability and toughness.
Journal Reference
Jiang, J. et al. (2025). Nature-inspired hierarchical building materials with low CO2 emission and superior performance. Nature Communications, 16(1). DOI: 10.1038/s41467-025-58339-8, https://www.nature.com/articles/s41467-025-58339-8
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