Adding carbon nanotubes and graphene nanoplatelets to cement doesn’t just improve its strength, it also gives it the ability to conduct heat and electricity, unlocking new possibilities for smart, energy-aware infrastructure.
Study: Thermal and Electrical Properties of Cement-Based Materials Reinforced with Nano-Inclusions. Image Credit: Mopic/Shutterstock.com
By reinforcing traditional cement composites with these advanced nanomaterials, researchers are pushing the limits of what cement can do. A recent study in Nanomanufacturing investigated how multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) affect the thermal and electrical behavior of cement-based materials, revealing critical differences in how these nano-additives perform across different cement matrices.
Background
Cement-based materials like concrete, mortar, and paste are construction mainstays widely used for their compressive strength, low cost, and availability. But when it comes to tensile strength and functional versatility, they fall short. Cracking under tensile stress and offering little in terms of energy-related properties, conventional cement leaves room for improvement.
To overcome these limitations, researchers have turned to nano-reinforcements. Among them, carbon nanotubes and graphene nanoplatelets stand out. These materials not only strengthen cement but also introduce conductive and thermal properties—key for applications ranging from self-sensing structures to energy-efficient buildings.
Experimental Approach
The study involved fabricating a range of cementitious composites using ordinary Portland cement, tap water, natural sand, and graded aggregates, combined with nano-reinforcements of either MWCNTs or GNPs. The CNTs had a high aspect ratio and purity exceeding 97 %, while the GNPs featured a lateral size of 7.2 μm, thickness of 3 nm, and 5–10 layers per platelet.
A fixed 1:1 weight ratio of nano-reinforcement to dispersant was used in all mixes. Morphological analysis via scanning electron microscopy (SEM) was performed before mixing. Seven compositions were developed—one plain mix and six modified with varying dosages of MWCNTs or GNPs (ranging from 0.2 % to 1.2 % by cement weight), for a total of 28 unique batches.
Preliminary mixes helped calibrate fresh-state consistency. Final specimens were cast into prismatic molds (10 × 10 × 40 mm3 and 100 × 100 × 400 mm3). Thermal behavior was assessed using infrared thermography, while electrical resistivity was measured with a custom probe featuring 22 circular pin electrodes. Each sample was isolated on an insulating platform, and results were averaged across five measurements.
What the Data Showed
The results revealed that both MWCNTs and GNPs improved conductivity, but their effectiveness depended on both the concentration and the type of cement matrix.
In cement paste, MWCNTs achieved a significant drop in electrical resistivity at just 0.6 % concentration—nearly three orders of magnitude—due to effective network formation. GNPs required double that concentration (1.2 %) to reach similar levels of conductivity, reflecting a higher percolation threshold. Both materials also enhanced thermal conductivity with increasing dosage, though CNTs outperformed GNPs at lower concentrations.
In concrete, a more complex and heterogeneous matrix, both nanomaterials showed a common percolation threshold of 1.0 %, where resistivity dropped by five to six orders. Thermal conductivity gains were also observed, though less dramatically—limited by aggregate content and porosity. CNTs again showed more impact at moderate dosages, but GNPs caught up at higher loadings.
One key insight was that the type of matrix did, in fact, matter. In simpler cement pastes, CNTs benefited from their high aspect ratio and dispersed more effectively, creating efficient conductive networks. In contrast, the bulk structure of concrete (rich in aggregates and voids) disrupted dispersion and connectivity, neutralizing the performance gap between CNTs and GNPs.
What This Means for the Future of Cement
This research highlights how nanomaterials can move cement beyond its traditional role as a structural material and toward multifunctional applications. With the right formulation, cement can become a medium for thermal management, electrical sensing, and even energy harvesting.
However, challenges remain. The study used just one type of CNT and GNP under lab-controlled conditions with optimized dispersion—conditions not easily replicated in the field. Real-world applications will require scalable dispersion methods, hybrid reinforcement strategies, and long-term testing under dynamic loads.
Journal Reference
Farmaki, S. G., Dalla, P. T., Exarchos, D. A., Dassios, K. G., & Matikas, T. E. (2025). Thermal and Electrical Properties of Cement-Based Materials Reinforced with Nano-Inclusions. Nanomanufacturing, 5(3), 13. DOI: 10.3390/nanomanufacturing5030013. https://www.mdpi.com/2673-687X/5/3/13
Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.