plastic limit

geology

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July 1, 2026

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In geology, the plastic limit is a measure of a soil's water content at which it transitions from a semi-solid state to a plastic state. It is one of the Atterberg limits, which are thresholds used to determine a soil's structural characteristics based on its water content. The plastic limit specifically indicates the point where a soil can be molded without crumbling. The difference between the liquid limit (where soil becomes liquid) and the plastic limit is known as the plasticity index. This concept is crucial in civil engineering for understanding soil behavior.12

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clay mineral
Clay-water relations
…water content increases, clays become plastic and then change to a near-liquid state. The amounts of water required for the two states are defined by the plastic and liquid limits, which vary with the kind of exchangeable cations and the salt concentration in the adsorbed water. The plasticity index (PI),…
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…water content increases, clays become plastic and then change to a near-liquid state. The amounts of water required for the two states are defined by the plastic and liquid limits, which vary with the kind of exchangeable cations and the salt concentration in the adsorbed water. The plasticity index (PI),…
Read More