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The phase composition of a particular cement can be quantified through a complex set of calculation known as the Bogue formula. To avoid the flash setting of concrete, due to the very fast hydration of the tricalcium aluminate ( C 3 A ), 2–5 wt. % calcium sulfate is interground with the cement clinker to prepare the cement powder.
Mohr–Coulomb theory is a mathematical model (see yield surface) describing the response of brittle materials such as concrete, or rubble piles, to shear stress as well as normal stress. Most of the classical engineering materials follow this rule in at least a portion of their shear failure envelope.
Alkali–aggregate reaction – Expansive chemical reaction damaging concrete Energetically modified cement – Class of cements, mechanically processed to transform reactivity Pozzolanic reaction – Capacity of silica-rich materials to react with calcium hydroxyde to form calcium silicate hydrates Pages displaying short descriptions of ...
4 ions to precipitate CaSO 4 ·2H 2 O . A fraction of SO 2− 4 ions can also be trapped, or sorbed, into the layered structure of C-S-H. [3] These successive reactions lead to the precipitation of expansive mineral phases inside the concrete porosity responsible for the concrete degradation, cracks and ultimately the failure of the structure.
An AFm phase is an "alumina, ferric oxide, monosubstituted" phase, or aluminate ferrite monosubstituted, or Al 2 O 3, Fe 2 O 3 mono, in cement chemist notation (CCN). AFm phases are important hydration products in the hydration of Portland cements and hydraulic cements.
Calcium aluminates can form complex salts in combination with different types of anions.Two series of calcium aluminates are known in cement chemistry: AFm and AFt phases, being respectively mono- or tri-substituted with a given divalent anion X (e.g. SO 2− 4, CO 2− 3, or hosting a divalent impurity such as SeO 2− 4 [3]...), or with two units of a monovalent anion, e.g. OH −, Cl − ...
Lead Paint Violations In Homes With Young Children. More than 75 percent of all violations for lead paint conditions in units with children under the age of 6 are found in areas where the poverty rate exceeds the city's average of 21 percent, according to a Huffington Post / WNYC analysis of government data.
In materials science, a general rule of mixtures is a weighted mean used to predict various properties of a composite material. [ 1 ] [ 2 ] [ 3 ] It provides a theoretical upper- and lower-bound on properties such as the elastic modulus , ultimate tensile strength , thermal conductivity , and electrical conductivity . [ 3 ]