A sustainable, low-carbon approach for improving the mechanical behavior ofclayey sand by incorporating seashell ash (SSA) and recycled polyethylene terephthalate (PET) fibers has been investigated in this study. The primaryobjective is to elucidate the mechanisticinteractions between CaO-rich SSA and PET fibers and determine how their combined action enhances strength and shear performance. To achieve this, unconfined compressive strength (UCS), indirect tensile strength (ITS), and direct shear tests were conducted on samples preparedcontaining different SSA and PET contents and subjected tovarious curing periods. According to the results obtained, the optimalcomposition was a mixture containing 30% clay, 7% SSA, and 1% PET. In addition, ultrasonic pulse velocity (UPV) was employed as a non-destructive method to evaluate cementitious bonding and structuraldevelopment. Moreover, UPV-based predictive models developed to estimate UCS and ITS indicated strong correlations. SEM analyses further revealed that the formation of pozzolanic gels and the interlocking of PET fibers played considerable roles in enhancing stiffness, density, and internal cohesion. Overall, this study provides new insight into the mechanicalmechanisms underlying the SSA-PET synergy and introduces UPV-based predictive models as effective tools for evaluating and designing sustainablestabilization strategies for clayey sand.
Zamanpour et al. (Tue,) studied this question.