In recent decades, crushed soft rocks are increasingly used as an economical substitute of granular soils for embankment construction and fill material. Generally, the durability characteristics of crushed rocks are determined by simple slaking tests more or less with a qualitative approach. However, for long-term performance analysis and risk assessment, there is a strong need to incorporate in conventional stress-strain models the time-dependent loss of strength parameters of such granular soils upon submergence in a more quantitative way.

This paper presents an experimental study conducted through monotonic torsional shear tests on reconstituted crushed rock specimens under saturated and dry conditions. The effects of water-induced deterioration of grains on stress-strain response and shear strength parameters are quantified by defining a degradation index based on pre and post-gradation analyses of each test specimen. The possible inter-relationships between this index and mechanical properties of granular soils are explored.