Road salt interactions with mudstones and implications for hillslope stability

 Presented by Abiodun Ayo-Bali | Geology & Environmental Science PhD Candidate, University of Pittsburgh

Abstract: 

Landslides represent a significant global hazard, resulting in thousands of fatalities and approximately $20 billion in annual property damage worldwide. Landslide susceptibility is fundamentally controlled by geologic factors, particularly the strength and cohesion of soils and rocks, which are governed by mineralogical composition. Weathering processes that degrade these materials can substantially increase slope instability and failure risk. Human activities now rival or exceed natural triggers as causes of landslides, with anthropogenic influences potentially accelerating weathering mechanisms. Of particular concern is the widespread application of sodium chloride as a road deicing agent in the United States, which introduces salts into geologic environments and may alter the mechanical properties of clay-rich slope materials through physio-chemical interactions. Despite extensive research on the mechanical aspects of slope failure, such as swelling and strain softening, the role of salt-induced physio-chemical weathering in landslide initiation remains poorly understood. This presentation includes: 1) spatial variability in expansive clay content in landslide prone clay materials across southwestern Pennsylvania. 2) implications of cyclic wetting (with saline brines, e.g., NaCl) and drying (including freshwater flushing) on geotechnical properties of clay-rich materials.