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.

The process by which a clay unit deforms as a result of drainage of pore water with non-equilibrium pressure produced by loading. During consolidation loading, the positive non-equilibrium pore water pressure causes water to flow out of the soil, resulting in a decrease in soil volume, also called consolidation settlement. The process of consolidation is usually accompanied by an increase in effective stress. This is different from drained shearing. In general, the loading rate for consolidation must be much smaller than drained shearing.
Cf., drained shearing, effective stress

For polymer nanocomposites, the volume around nanoparticles where the degree of freedom of movement of the polymer has been lowered. This region involves the interaction between the polymer and nanoparticle and is distinguished by having properties that are different from the bulk polymer properties. The volume of this region is dependent upon the strength of the interaction of the polymer and nanoparticle and the flexibility of the polymer. The concept, for example, explains why a gas diffusion coefficient of a polymer nanocomposite may differ from the bulk polymer. Gas diffusion may also be affected by the arrangement of clay particles that leads to a “tortuous path” and a reduction of diffusion through the nanocomposite.

A reaction vessel with inlet and outlet flow and whose contents are stirred. CSTRs are commonly operated at steady state, but they may alos function transiently.
Cf., batch reactor, chemostat, plug flow reactor