Water Stability of Light Weight Soil Amended with Expanded Polystyrene Beads

Abstract

To reveal the durability of light weight soil ground under water environment conditions, the influence laws of soaking time and dry–wet cycle times on mechanical properties of light weight soil are researched by density tests, unconfined compressive strength tests, water absorption tests and mass loss rate tests. Due to chemical compositions in the light weight soil interacting with each other, a kind of network cemented structure containing soft inclusions (expanded polystyrene beads) is formed in the specimens. Enough water has been provided for the mixed soil in the physical–chemical reaction process in the experiments, hydrolysis and hydration of cement, ion exchange, hardening reaction and carbonation action occur continuously. Under long term soaking conditions, the physical properties of light weight soil are extremely stable, the network cemented structure is the physical basis for the hydrophobicity. When soaking time is more than 90 days, the unconfined compressive strength of the specimens will reach a stable value gradually. Similarly, light weight soil does not appear cracking phenomenon, and keep the mechanical properties and material density stable under long term dry–wet cycle. Thus light weight soil has good water stability and durability, it is recommended that light weight soil can be widely used in civil engineering, such as ground improvement, soft subgrade engineering, embankment heightening, slope repair, excavation backfill, pipeline backfilling and so on.