Effect of temperature on the performance of solidified/stabilized petroleum-polluted soil: Pollutants fate and geotechnical properties

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Solidification/stabilization (S/S) technology is a predominant method for treating petroleum-polluted soil. However, existing studies lack investigation of the stability of solidified petroleum-polluted soil (SPS) under different temperatures, as temperature fluctuations could cause the re-release of immobilized pollutants and damage the structure of SPS. In this work, the physicochemical characteristics and mechanical performance of SPS with various initial petroleum contents (30–150 mg/g) at different temperatures (−20–60 °C) were studied. The functional groups and crystal phase structure of SPS with an initial petroleum content of 30 to 150 mg/g remained largely unchanged at −20-60 °C. Although the shape of the solidified products changed, the petroleum pollutants could remain stable, with a maximum migration amount of only 0.15 to 0.22 mg/g. Additionally, the solidification could weaken the effect of temperature on the soil and petroleum pollutants, increase the freezing temperature of the unsolidified petroleum-polluted soil (UPS), and reduce the expansion coefficient. The primary solidification product formed in the SPS exhibited good thermal stability at 60 °C, endowing it with strong thermal resistance. By contrast, the low temperature of −20 °C not only affected the strength of the SPS, but also induced frost heaving and micro-crack expansion. This work provides new insight into the temperature-dependent behavior of SPS and could facilitate the practical engineering reutilization of S/S treatment of petroleum-polluted soil.