Synthesized Approach for Evaluating the Integral Suspension Pressure (ISP) Method and the Hydrometer in the Determination of Particle Size Distribution

Different techniques have been developed in the 20th and 21st centuries to address the study of particle size distribution in fine materials. Most of these techniques are based on gravitational sedimentation processes. The modern method used in this research bases the measurement on the change in pressure of the aqueous medium caused by the progressive settling of fine particles. Different materials were evaluated within the study to compare the results of the integral suspension pressure (ISP) method with a traditional approach used worldwide, such as hydrometers. Although the ISP method is considered promising and reliable in measuring the particle size distribution of the fine fraction, current literature lacks comparisons with traditional methods. This aspect would help in the definitive validation of the technique and its use in practical engineering. The hydrometer recorded silt content was greater than ISP over the whole range of measurements, especially in yellow kaolin, in which the silt content is more than 40%. Compared to the hydrometer method, the ISP presented a tendency to misclassify the soil texture of bentonite due to the high clay content. The considerable differences, especially in clays with finer particles such as bentonite, demonstrate that the modern ISP technique can detect very fine projected materials within the particle size distribution compared to conventional methodologies. The study's objective is mainly to compare both methods, given the important technological evolution that the ISP method presents in relation to the hydrometer.