High Salinity Increases the Fluidity and Decreases the Yield Stress and Erosion Threshold of Sand-Clay Mixtures – New Data in 2025

Abstract

This dataset presents raw videos and frames captured from flume erosion test and rheological measurements on bentonite clay - silica sand mixture at seven different salinity concentrations (0ppt, 3ppt, 5ppt, 10ppt, 15ppt, 20ppt, 35ppt). There are three replicates per each experiment that make it: - 21 flume tests (about 30 minutes after sample preparation) (3 rep for each salinity concentration) - 21 flow sweep tests (6hrs after preparation) (3 rep for each salinity concentration) - 21 amplitude oscillation tests (6hrs after preparation) (3 rep for each salinity concentration) - 21 flow sweep tests (30hrs after preparation) (3 rep for each salinity concentration) - 21 amplitude oscillation tests (30hrs after preparation) (3 rep for each salinity concentration)

Video data for each flume experiment include side-view and top-view for all runs and there is angled-view for some tests. Cameras were synchronized by briefly turning the flume room lights off and on at the start of each test. Erosion observed from top and angled views, while simultaneously, the water depth is measured using the corresponding frames from the side camera. Having water depth in erosion time, critical shear stress calculated by slope method.

Rheological data consist of flow sweep tests and oscillatory amplitude tests at 6hrs post-preparation, give us insights about viscosity, shear thinning behavior of the mixture, yield stress and flow-point stress and effect of ageing.

Together, these data quantify how increasing salt concentration collapses the electrostatic double layer, lowers yield and flow-point stresses, and reduces—but does not eliminate—the shear stress required to erode sand-clay beds.