A New Tool to Effectively Control Groove Dimensions in Low-Plasticity Soils during the Casagrande Cup Liquid Limit Test

One of the most commonly used methods to determine the liquid limit (LL) of soil is based on the Casagrande apparatus, in which grooving with specially designed tools is required for its determination. Given the impossibility of obtaining a groove of controlled dimensions in soils of low cohesion with the standardized flat, curved, or hollow grooving tools (thus assuming a certain degree of uncertainty in the final results obtained), this paper introduces a new groov-ing tool, which, in combination with the curved one, does allow obtaining grooves of equal dimensions in low-plasticity soils to those obtained with the flat tool in cohesive soils. In this sense, the application of the new tool would reduce the uncertainty in the results obtained when using the curved one in low-cohesion soils, because while it does not control the depth of the groove, the proposed device does. In addition to showing how to use this new tool correctly, a series of drawings with its dimensions are also presented to facilitate its incorpo-ration into the LL standards as well as its acquisition by those who are interested in its use.

Automated summary

This paper introduces a new grooving tool that allows obtaining grooves of equal dimensions in low-plasticity soils as those obtained with the flat tool in cohesive soils, reducing uncertainty in the results.