Soil texture The number on the hydrometer that is visible (above the soil solution) is recorded. A blank (containing only water and the dispersing agent) is used to calibrate the hydrometer. The values recorded from the readings are used to calculate the percent clay, silt and sand. The blank is subtracted from each of the three readings. The calculations are as follows: Percent silt = ( dried mass of soil - (sand hydrometer reading - blank reading) / (dried mass of soil) *100 Percent clay = (clay hydrometer reading - blank reading) / (dried mass of soil) *100 Percent sand = 100
Sand equivalent test Sand equivalent test The sand equivalent test quantifies the relative abundance of sand versus clay in soil. It is measured by standardized test methods such as ASTM D2419, AASHTO T176, and EN 933-8. The test is used to qualify aggregates for applications where sand is desirable but fines and dust are not. A higher sand equivalent value indicates that there is less clay‐like material in a sample. During the test, material from the test specimen that can pass through a No. 4 sieve is mixed with solutions of calcium chloride, formaldehyde and glycerin in a cylinder. The content is then