The ratio of change in void ratio to the change in the logarithmic effective stress when a clay is subject to consolidation.
Cf., compressibility

The stage of consolidation compression occurring under constant effective stress after primary compression, where a change in effective stress occurs.
Syn., drained creep;
Cf., compression, primary; creep.

The stage of consolidation compression occurring under an effective stress imposed after primary compression. Whereas primary compression or consolidation is mainly caused by the escape of excess pore water pressure accompanied by the change in effective stress, secondary compression occurs only under a constant effective stress.
Syn., drained creep;
Cf., compression, primary; creep.

A material property commonly determined for cements (e.g., Portland cements, also geopolymers) to evaluate their resistance to compression by a load. The compressive strength is given as the applied force at the point of failure (in Newton, N), usually at the peak force, divided by the initial area over which the force was applied (in m²). Compressive strength is measured from the amount of stress (force) that is gradually increased until the structure of the material is unable to absorb any more energy, leading to fractures, brittle failure, or excessive plastic deformation.
Cf., Portland cement, geopolymer

A building material comprised of a binder (e.g., cement, Portland cement) and aggregates (e.g., sand, gravel, crushed stone). With the addition of water to the dry binder, a hydraulic reaction causes calcium silicate hydrate (CSH) phases to form. This process is called setting or hardening and leads to the strength of the cement/concrete.
Cf., calcium silicate hydrate (CSH) phases, Portland cement, cement

Although not a true equilibrium constant, a conditional stability constant describes the equilibria of complex formation at ambient solution conditions. For example, a conditional stability constant may be used when pH is fixed at a specific value; the conditional stability constant would then vary with pH. Thus, the complex will be either strong or weak depending on solution conditions, in this case with pH and possible protonation of the ligand. In other cases, temperature or ionic strength may alter metal to ligand strength, which changes the conditional stability constant. Conditional stability constants are commonly used to describe surface complexation reactions.
Syn., apparent stability constant; See also ligand

An obsolete, local term for montmorillonite from Confolens, Charente, France.

Congruent dissolution is where the same ratio of atoms present in the parent phase is released to the solution. This type of dissolution may be referred to as “stoichiometric” dissolution.
Cf., congruent melting, incongruent dissolution, incongruent melting

Upon heating to form a liquid, the liquid (melt) has the same composition as the solid.
Cf., congruent dissolution, incongruent dissolution, incongruent melting

An obsolete varietal term for willemseite.