ASTM C128:15 pdf free download – Standard Test Method for Relative Density (Specific Gravity) and Absorption of Fine Aggregate.
8.2 Decant excess water with care to avoid loss of fines (see also Appendix X I), spread the sample on a flat nonabsorbent surface exposed to a gently moving current of warm air, and stir frequently to secure homogeneous drying. Employ mechanical aids such as tumbling or stirring to assist in achieving the saturated surface-dry condition, if desired. Continue this operation until the test specimen approaches a free-flowing condition. Follow the rocedure in 8.3 to determine if surface moisture is still present on the constituent tine aggregate particles. Make the first trial tor surface moisture when there is still some surface water in the test specimen. Continue drying with constant stirring and test at frequent intervals until the test indicates that the specimen has reached a surface-dry condition. If the first trial of the surface moisture test indicates that moisture is not present on the surface, it has been dried past the saturated surface-dry condition. In this case, thoroughly mix a tIw millilitres of water with the line aggregate and permit the specimen to stand in a covered container for 30 mm. Then resume the process of drying and testing at frequent intervals for the onset of the surface-dry condition.
8.3 Test Surface Moisture— Hold the mold firmly on a smooth nonabsorbent surface with the large diameter down. Place a portion of the partially dried tine aggregate loosely in the mold by filling it to overflowing and heaping additional material above the top of the mold by holding it with the cupped fingers of the hand holding the mold. Lightly tamp the tine aggregate into the mold with 25 light drops of the tamper. Start each drop approximately 5 mm above the top surface of the tine aggregate. Permit the tamper to fall freely under gravitational attraction on each drop. Adjust the starting height to the new surface elevation after each drop and distribute the drops over the surface. Remove loose sand from the base and liii the mold vertically. If surface moisture is still present, the fine aggregate will retain the molded shape. Slight slumping of the molded fine aggregate indicates that it has reached a surface-dry condition.
8.3.1 Some tine aggregate with predominately angularshaped particles or with a high proportion of tines does not slump in the cone test upon reaching the surface-dry condition. Test by dropping a handful of the tine aggregate from the cone test onto a surface from a height ot 1(X) to 150 mm, and observe for fines becoming airborne: presence of airborne tines indicates this problem. For these materials, consider the saturated surface-dry condition as the point that one side of the fine aggregate slumps slightly upon removing the mold.
Nom 2—The following criteria have also been used on materials that do not readily slump:
(1) Provisional Cone Test— Fill the cone mold as described in 8.3 except only use 10 drops of’ the tamper. Add more fine aggregate and use 10 drops of the tamper again. Then add material two more times using 3 and 2 drops of the tamper, respectively.