1 Oct 2020

Laboratory Evaluation of Aquablok™ Erosion Resistance: Implications for Geotechnical Applications

Abstract: AquaBlok™ (AB) is a commercial product traditionally used as an alternative material for contaminated sediment capping applications. Previous studies of AB capping performance have reported enhanced stabilization through increased erosion resistance. Subsequently, AB has been considered for use as an alternative levee repair material due to its cohesive properties. Through a series of laboratory experiments, this study investigated the erosion behavior of new AquaBlok formulations (10%, 20%, and 30% clay by weight) under increased shear stresses previously unachievable in the previous tests. The new AquaBlok formulations were tested in non-compacted and compacted states to simulate the physical properties in capping and levee repair applications. In the non-compacted state, excess hydration of the clay matrix extended approximately 5 cm below the bed surface, which greatly reduced erosion resistance and was independent of clay percentage. Below this horizon, critical shear stress increased, and erosion rates decreased, with clay percentage, respectively. However, this does not consider a continuous change in hydration state when exposed to free water. In the compacted state, erosion rates were greatly arrested, with measureable erosion only possible under the maximum applied shear stress (24 Pa). The results are discussed in the context of capping and levee applications.