Cements Flashcards
is a type of cement that is used as the binding agent in concrete. It is made by heating limestone and clay to high temperatures in a kiln.
portland cement
when was Portland cement invented and by who
invented in 1824 by Englishman Joseph Aspdin and patented in 1825.
where did the name portland cement come from
The name comes from its similarity to the stone quarried on the Isle of Portland, Dorset, England.
Portland cement is one of the most widely used high-carbon cement in use today because it has a large amount of silica that makes up __% of its weight
13%
major reason why portland cement is so widely used.
its low heat of hydration
The limestone version of portland is called
“caliche”
the clay version of portland cement is called
“portland”
The raw material that is commonly used in the manufacturing of portland cement mainly consists of
lime, silica, alumina and iron oxide
Two types of materials are necessary for the production of portland cement
one rich in calcium calcareous, such as limestone, chalk, etc., and one rich in silica (argillaceous) such as clay.
known as cement rock, found in New
Jersey and the Lehigh district of
Pennsylvania.
argillaceous limestone
Usual products for general construction. There are other types of
this cement, such as white, which contains less ferric oxide, oil-well cement, quick-setting cement, and others for special uses.
TYPE I - REGULAR PORTLAND CEMENTS
Use where moderate heat of hydration is required or for general
concrete construction exposed o moderate sulfate action. The
heat evolved from these cements should not exceed 295 and 335
1/g after 7 and 28 days respectively
TYPE II - MODERATE HEAT OF HARDENING AND SULFATE RESISTING PORTLAND CEMENTS
Made from raw materials with a lime- to-silica ratio higher than
that of Type I cement and are ground finer than Type I cements.
They contain a higher proportion of tricalcium silicate (CS) than
regular portland cements.
TYPE III - HIGH EARLY STRENGTH (HES)
contain a lower percentage of tricalcium silicate (C3S) and
tricalcium aluminate (C3A), thus lowering the heat evolution.
TYPE IV - LOW HEAT PORTLAND CEMENT
composition or processing resist sulfates better than other four
types. It is used when high sulfate resistance is required.
TYPE V - SULFATE RESISTING
PORTLAND CEMENTS
a special cement which has air bubbles introduced in the
cement or concrete that provides the space for expansion of
minute droplets of waters in the concrete due to freezing and
thawing and protects from cracks and damage of concrete
AIR ENTRAINMENT
a material which is not cementitious in itself but becomes admixture with lime. It is with the
same strength with the Portland cement. Its
advantage is that it resists the corrosive action
of saline solutions and seawater much better.
pozzolans
manufactured by fusing a mixture of limestone and bauxite. It is characterized by a very rapid rate of development of strength and superior resistance to seawater and sulfate-bearing water.
high alumina cements
silica-filled, chemically setting silicate cements withstand all concen- trations of inorganic acids except hydrofluoric. They are not suitable at pH values above or in the presence of crystal-forming systems.
silicate cements
- homogeneous plasticized filled sulfur ingots possessing low coefficients of expansion.
- are resistant to nonoxidizing acids and salts but should not be used in the presence of alkalies, oils, greases, or solvents.
sulfur cements
polymer-bonded concretes and usually contain no portland cement. These products consist of aggregate plus resins such as epoxy, methyl methacrylate, or polyester.
polymer concrete
discovered by the French chemist Sorel and
sometimes called Sorel’s cement, is produced by the exothermic action of a 20% solution and magnesium chloride on a blend of magnesia obtained by calcining magnesite and magnesia obtained from brines.
magnesium
oxychloride cement
is the cheapest, most widely used alkali in
the world.
lime
- usually gray, but it may also be white, yellow or
brown. - a soft rock and is easily scratched.
- sedimentary rock composed principally of calcium carbonate (calcite) or the double carbonate of calcium and magnesium
(dolomite). - It is commonly composed of tiny fossils, shell
fragments and other fossilized debris.
lime
the first definite
written information concerning lime was handed down from the
Romans
is the 5th most abundant element in the
Earth’s crust and limestone/chalk forms 20% of the world’s sedimentary rock. Some of the earliest evidence
for the use of lime dates back roughly 10,000 years ago.
calcium
It serves as a basic raw material in the production of calcium salts and for improving the quality of certain soils.
lime
Lime has always been a cheap commodity because
limestone deposits are readily available
in so many sections of the United States.
obtained from deposits of limestone, marble, chalk, dolomite, or oyster shells.
carbonates of calcium and magnesium
is preferred as a starting material because of the high-calcium lime that results.
pure limestone
two types of kiln used
to produce lime
rotary and vertical kiln
a widely used industrial chemical. As a
marble chips, it is sold in many sizes as a
filler for artificial ston, for the neutralization
of acids, and for chicken grit
calcium carbonate
is employed in abrasives and in soaps.
marble dust
Use as a
depilatory in
the tanning
industry and
cosmetics.
calcium sulfide
to lay dust on
highways and
to melt ice and
snow in winter
halide salts
use as
insectiside and
fungicide
calcium arsenate
The acetate was formerly pyrolyzed in large amounts to produce acetone, but now it is employed largely in the dyeing of textiles.
calcium acetate
The lactate is sold for use in medicines and in foods as a source of calcium; it is an intermediate in the purification of fermentation lactic acid.
calcium lactate
is one of the most widely distributed elements, occupying 1.9 percent of the earth’s crust. It occurs usually in
the chloride, silicate, hydrated oxide, sulfate, or carbonate, in
either a complex or in simple salts.
magnesium
first became available commercially shortly before 1914, when the Germans initiated production, using magnesium chloride from the Stassfurt deposits as the raw material
magnesium metal
important domestic sources of magnesium
salts are
seawater. certain salt wells,
bitterns from sea brine, salines, dolomite,
and magnesite (MgCO3)
used extensively for
refractories and insulating compounds, as well as
in the manufacture of rubber, printing inks,
pharmaceuticals, and toilet goods.
magnesium compounds
magnesium
compound employed as fillers
in inks, paints, and
varnishes.
magnesium carbonates
Oxide is formed on
heating
magnesium carbonate
Hydroxide
is made from
seawater
prepared by the action of sulfuric acid on magnesium carbonate or hydroxide.
magnesium sulfate
made from
hydrochloric acid and
magnesium
hydroxide.
magnesium chloride
includes asbestos and
talc.
magnesium silicates
is a
fibrous,
noncombustible
mineral.
asbestos
is found
naturally in soapstone.
talc
