Dynamic Properties of Lightweight Cellular Concrete for Geotechnical Applications

Lightweight cellular concrete (LCC) materials have been used in various civil engineering applications for several decades. In this study, the dynamic behavior of LCC materials was evaluated for possible geotechnical applications, such as mechanically stabilized earth (MSE) retaining walls. Lightweight cellular concrete materials having four different unit weights were subjected to various amplitudes of sinusoidal waves at effective normal stresses ranging from 25 to 350 kPa. Results from this study show that the effective normal stress influenced the shear strength and stiffness more than the unit weight of the LCC materials. The backbone curves could be represented with a hyperbolic function, which can be developed for a known effective normal stress using the equations proposed in this paper. The maximum shear moduli of the LCC materials increased with a decrease in the unit weight and an increase in the effective normal stress. Likewise, the rate of reduction in normalized shear modulus ($G/G_{\text{max}}$) with strain also decreased with an increase in effective normal stress applied during seismic loading. Moreover, the damping ratio decreased with an increase in shear strain up to certain shear strain, which ranged from 0.25 to 0.35% for effective normal stresses of 25 and 350 kPa, respectively, and increased with shear strain after that transitional shear strain. The damping ratio of each type of LCC material tested was similar at the highest shear strain, i.e., 0.5% at a given effective normal stress. The results from this study can be used to evaluate the shear strength and deformation of the LCC materials in various geotechnical projects, such as in the backfill of MSE walls.