Pozzolana is a naturally occurring siliceous or siliceous and aluminous pozzolanic material or pozzolan with a volcanic origin.
Cf., pozzolan, pozzolanic activity
Pozzolana is a naturally occurring siliceous or siliceous and aluminous pozzolanic material or pozzolan with a volcanic origin.
Cf., pozzolan, pozzolanic activity
Pozzolanic activity is the degree or extent of the chemical reactions in Portland cement and other amorphous aluminosilicates (e.g., metakaolin, some volcanic ashes, fly ash) between a pozzolan and dissolved Ca(OH)2, usually measured in terms of reaction time or reaction rate.
Cf., pozzolan, pozzolana
The maximum consolidation pressure or stress that a clay mass has ever been subject to, including the current stress acting on the clay.
Syn., preconsolidation stress, maximum consolidation stress/pressure
The maximum effective stress to which a clay deposit has been subjected during its entire formation and consolidation process, including any natural processes (e.g., sedimentation, compaction, uplift, ground water fluctuation) or man-made loading or unloading events (e.g., groundwater pumping, construction). Thus, the preconsolidation stress is the maximum value of all past and current effective stresses that have caused the clay to consolidate. The maximum past effective stress is generally determined experimentally by measurement of one-dimensional elastic and plastic deformation that occurs during consolidation, or one-dimensional stress-strain compression curves, or from known events, such as specific sea-level changes, groundwater table fluctuations, etc.
Syn., preconsolidation pressure
Cf., overconsolidation ratio
An obsolete term for paragonite.
A trioctahedral member of the true mica group. The end-member formula is NaMg2Al(Al2Si2)O10(OH)2. The first occurrence of preiswerkite is from a metamorphosed basic dike in the Geisspfad ultramafic complex in the Penninic Alps. The 1M, 2M1 and 1Md polytypes have been identified.
Cf., aspidolite, eastonite
See hollandite.
Primary mineral is a mineral of igneous, metamorphic or sedimentary origin now residing in weathering, sedimentary, diagenetic or hydrothermal environments where many alteration processes operate. A primary mineral is present in the parent rock; thus, in soils and other weathering or alteration environments, a primary mineral is one that remains from the parent rock whereas a secondary mineral is one that forms as the rock weathers.
Cf., secondary mineral
A crystal shape where one dimension is considerably greater than the other two.
A discredited name for an often iron-rich, but Si-poor chlorite.