Optical and physical properties of laponite for use as clay surrogate in geotechnical models

Abstract

Laponite has emerged as a particularly promising material for use as a soft clay surrogate in geotechnical modeling, as it provides a relevant range of transparency, plasticity, and overall geotechnical behavior. This paper presents an investigation of the significant factors affecting the transparency of laponite for its use in physical geotechnical models. Image analysis techniques and complementary optical tests were conducted to gain an understanding of the factors causing changes in optical clarity. Aging time, laponite content, and rheological additive dosage were found to be the most significant factors affecting the transparency of laponite. Specifically, the ratio between the rheological additive dosage and laponite content (additive mass ratio) was found to serve as a relevant index to define the material’s optical behavior, and its use facilitated the determination of the optimum laponite and additive contents. The presence of inclusions within the internal laponite structure, such as trapped air pockets and unhydrated laponite crystals, identified as the key factor compromising optical clarity, could be ultimately associated with the selection of insufficient dosages of rheological additive. Overall, laponite was identified as a viable surrogate of natural clays suitable for models requiring comparatively large in-depth visualization. Copyright © 2021 by ASTM International