In the quest for sustainable construction materials, a team of researchers led by Xia Bian from Hohai University’s State Key Laboratory of Precision Blasting has uncovered a promising avenue for enhancing the mechanical properties of stabilized soil using biochar. Their findings, published in the journal *Developments in the Built Environment* (which translates to *Advances in the Built Environment*), offer a low-carbon strategy for the energy sector, particularly in the reuse of underground excavation slurries.
The study delves into the effects of biochar on magnesium oxide (MgO) activated slag stabilized slurry soil, a material commonly used in various construction applications. By incorporating biochar, the researchers observed significant improvements in the soil’s mechanical properties, including a notable increase in unconfined compressive strength (UCS) and a reduction in compressibility.
“Biochar significantly reduces the density and post-curing water content of stabilized soil,” explains Bian. “This leads to a more efficient material with enhanced mechanical performance.”
The research team conducted a series of physical, mechanical, and microstructural analyses, including unconfined compressive strength tests, one-dimensional compression tests, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Their findings revealed that biochar not only improves the soil’s strength but also refines its microstructure by absorbing free water and acting as nucleation sites for cementitious phases like C-S-H (calcium silicate hydrate) and hydrotalcite.
One of the most striking results was the identification of an optimal biochar content of 20%, which led to a 48.1% increase in 28-day UCS compared to biochar-free samples. Additionally, the compression index (Cc) showed significant improvement, decreasing by 24.1% (14-day) and 23.4% (28-day) with the optimal biochar content.
The implications of this research for the energy sector are substantial. As the demand for sustainable and low-carbon construction materials grows, the integration of biochar into stabilized soil offers a viable solution for the energy sector, particularly in projects involving underground excavation and slurry management.
“This study provides a novel approach to enhancing the mechanical properties of stabilized soil, which can be particularly beneficial for the energy sector,” says Bian. “By optimizing the use of biochar, we can achieve significant improvements in material performance while reducing the carbon footprint of construction projects.”
The findings of this research not only contribute to the advancement of sustainable construction practices but also pave the way for future developments in the field. As the energy sector continues to seek innovative solutions for reducing its environmental impact, the integration of biochar into stabilized soil offers a promising avenue for achieving these goals.
In the broader context, this research highlights the potential of biochar as a valuable additive in construction materials, offering a sustainable and low-carbon alternative to traditional methods. As the industry continues to evolve, the insights gained from this study will undoubtedly shape future developments in the field, driving the energy sector towards a more sustainable and environmentally friendly future.