Characterizing the Degradation Threshold of Biocemented Sands for Transportation Infrastructure: Insights from Resonant Column Test

Biocemented soils present a promising sustainable alternative to traditional Portland cement and asphalt in road embankment construction and remediation. However, the cyclic loading experienced by transportation infrastructures like roads over extended periods explicitly leads to performance degradation. Biocementation, achieved through Microbially Induced Calcite Precipitation (MICP) using ureolytic bacteria or Enzyme-Induced Calcite Precipitation (EICP) with urease enzymes, precipitates calcium carbonate (calcite) as a bonding agent within the soil matrix. Despite the environmental appeal of biocemented soils, their durability under cyclic and repeatable loads remains relatively unexplored. This paper investigates the modulus degradation of biocemented sand subjected to cyclic loading, considering various strain amplitudes and confinement levels. The experimental program involves subjecting two distinct specimens—one uncemented and the other cemented—to three confinement levels (50, 100, and 200 kPa). Each specimen undergoes incremental torque amplitudes to elucidate stiffness behavior across a spectrum of strain levels. Additionally, resilient modulus estimates are obtained for different strain levels, and a critical strain threshold is identified. The primary objective of this research is to unveil fatigue susceptibility criteria, offering crucial insights into the performance of biocemented soils. By doing so, this study contributes to the advancement of sustainable and durable infrastructural solutions, particularly in the context of road construction and maintenance.