A new method for weakening slaking of collecting eroded aggregates by water erosion

Purpose In most of previous studies about aggregate breakdown caused by water erosion, a critical process that water inevitably fragments the eroded aggregates by water erosion again is generally ignored. This will reduce the accuracy of research results. Hence, alcohol has been added to the collecting device of eroded aggregates to weaken the slaking of eroded aggregates by the researchers, but the optimal alcohol-to-water ratio for protecting the size fraction distribution of eroded aggregates remains unclear. Materials and methods Aggregate with a size fraction of 2–5 mm obtained by dry sieving of black soil in Northeast China was selected as the research object to analyse the effects of five alcohol-to-water ratios on aggregate characteristics and their variation with soaking time. Results and discussion The results showed that the size distribution in terms of mass percentage under different soaking times was similar. For the same soaking time, the mass percentage of 2–5-mm aggregates gradually decreased with decreasing alcohol ratio, but the aggregates with the second-highest mass percentage were gradually distributed among smaller size fractions. Compared with the alcohol soaking aggregates, the mean weight diameter ( MWD ) of the aggregates soaked in the other ratio of alcohol-to-water decreased gradually with the increase of soaking time, and the disintegration of the aggregates was the most evident at the initial stage of soaking. A percentage of aggregate destruction ( PAD ) of 20% served as the dividing line to evaluate the stability of soil aggregates. In this case, eroded aggregate collection should be completed within 12 min at an alcohol-to-water ratio of 1:1. Alternatively, eroded aggregate collection should be completed within 6 min at an alcohol-to-water ratio of 2:3. Conclusions The above results can provide a reference for improving the accuracy of data collection regarding eroded aggregates. Especially in the study of water erosion which needs to collect eroded aggregates, alcohol can be added to the collecting device before the experiment. The amount of alcohol should be added according to the amount of water that may be generated, so as to protect eroded aggregates and weaken the slaking of eroded aggregates.