Estimating Atterberg limits of soils from hygroscopic water content

A number of environmental, agronomic and engineering applications require knowledge the Atterberg limits (liquid limit, LL; plastic PL) plasticity index, PI soils. The tedious costly nature standard experimental methods, as well challenges with measurement repeatability motivated development regressions more sophisticated techniques to estimate from other properties such clay content, cation exchange capacity (CEC), soil specific surface area. amount water adsorbed particle surfaces at relative humidity (RH) < 95% is intimately linked these properties, which suggests that hygroscopic content (wh) may be a better predictor limits. present study (i) proposes regression models LL, PL, wh different values ranging 10 90% considering sorption hysteresis, (ii) compares performance comprise clay, silt organic carbon contents CEC. For model development, was measured by adsorption desorption for 168 samples varied widely in terms geographic origin, mineralogy, content. LL PL were determined drop cone penetrometer rolling device, respectively. Regression developed both directions nine RH between 90%. 44 independent samples, estimated accurately (e.g., RH, RMSE r2 6.43% & 0.89; 3.95% 0.83 6.69% 0.79, respectively). There no clear effect direction on estimation accuracy. higher tended compared lower RH. superior estimating based or PI, CEC performed slightly than models. Thus, single measure can provide reliable estimates PI.