In the world of road construction, expansive clay subgrades have long been a thorn in the side of engineers and builders. These problematic soils, which swell and shrink with changes in moisture, can lead to costly maintenance and repairs. But a recent study published in the *Journal of Innovative Transportation* (translated from Turkish as *Journal of Innovative Transportation*) offers a promising solution: sodium hydroxide (NaOH).
Muhammed Tanyıldızı, a researcher at Bitlis Eren University in Turkey, led the investigation into using NaOH to stabilize expansive subgrades. The study, which evaluated the effect of NaOH with different molarities on the properties of expansive subgrade, could have significant implications for the construction industry, particularly in regions where expansive soils are prevalent.
The research team conducted a series of tests, including consistency, free swell, compaction, unconfined compressive strength (UCS), and California bearing ratio (CBR) tests, at three different curing durations: 1, 7, and 28 days. The results were encouraging. “We found that the liquid limit, plasticity index, and swelling potential of the soil decreased steadily with increasing molar concentrations of NaOH solution,” Tanyıldızı explained. “This means that the soil becomes more stable and less prone to swelling and shrinking.”
The study also revealed that the soil’s maximum dry density (MDD) and the optimum moisture content (OMC) increased consistently with the NaOH solution. Perhaps most impressively, the researchers achieved an approximately 150% and 285% increase in the UCS and CBR values of the pure soil after 28 days of curing with a 15 M NaOH solution.
So, what does this mean for the future of road construction? According to Tanyıldızı, the findings suggest that NaOH could be a sustainable and effective solution for stabilizing expansive clayey subgrades. “This could lead to significant cost savings in the long run, as well as improved road performance and durability,” he said.
The study’s results are particularly relevant for the energy sector, where road construction is often required to access remote or challenging terrains. By using NaOH to stabilize expansive subgrades, energy companies could reduce maintenance costs and improve the longevity of their road networks.
While the research is still in its early stages, the findings offer a glimpse into a future where expansive soils are no longer a roadblock to progress. As Tanyıldızı and his team continue to explore the potential of NaOH, the construction industry watches with interest, eager to see how this innovative solution could shape the roads of tomorrow.