ASTM D4318-17e1 PDF Download

The ASTM D4318-17e1 standard provides guidelines for determining the liquid limit, plastic limit, and plasticity index of soils. These test methods are commonly used in engineering classification systems to characterize fine-grained soils and specify the fine-grained fraction of construction materials. They are also used to correlate soil properties with engineering behavior such as compressibility, permeability, compactibility, shrink-swell, and shear strength.

The liquid limit and plastic limit of a soil can be used to express its relative consistency or liquidity index, while the plasticity index, along with the percentage finer than a 2-µm particle size, can be used to determine its activity number. These methods can also be used to evaluate the weathering characteristics of clay-shale materials, as the liquid limits of these materials tend to increase when subjected to repeated wetting and drying cycles.

Furthermore, the standard provides two specimen preparation procedures, two methods for determining the liquid limit, and two procedures for rolling portions of the test specimen when performing the plastic limit test. The liquid limit and plastic limit, along with the shrinkage limit, are collectively known as the Atterberg limits, which distinguish the different consistency states of plastic soils.

It is important to note that the results obtained from these test methods are influenced by the competence of the personnel conducting the tests and the suitability of the equipment and facilities used. Compliance with the criteria outlined in Practice D3740 is recommended to ensure reliable results. However, it is cautioned that compliance with Practice D3740 does not guarantee reliable results, as they depend on various factors. The standard also provides guidelines for significant digits and rounding of observed and calculated values in accordance with Practice D6026.