Civil Engineering Reference
In-Depth Information
Fig. 2-17. High early strength cements are used where early concrete strength is needed, such as in (left to right) cold weather
concreting, fast track paving to minimize traffic congestion, and rapid form removal for precast concrete. (65728, 59950, 68668)
top). Type V cement, like other portland cements, is not
resistant to acids and other highly corrosive substances.
ASTM C 150 (AASHTO M 85) allows both a chemical
approach and a physical approach (ASTM C 452 expansion
test) to assure the sulfate resistance of Type V cement.
Either the chemical or the physical approach can be speci-
fied, but not both.
White Portland Cements
White portland cement is a true portland cement that
differs from gray cement chiefly in color. It is made to
conform to the specifications of ASTM C 150, usually Type
I or Type III; the manufacturing process is controlled so that
the finished product will be white. White portland cement
is made of selected raw materials containing negligible
amounts of iron and magnesium oxides—the substances
that give cement its gray color. White portland cement is
used primarily for architectural purposes in structural
walls, precast and glass fiber reinforced concrete (GFRC)
facing panels, terrazzo surfaces, stucco, cement paint, tile
grout, and decorative concrete (Fig. 2-18). Its use is recom-
mended wherever white or colored concrete, grout, or
mortar is desired. White portland cement should be speci-
fied as: white portland cement meeting the specifications of
ASTM C 150, Type [I, II, III, or V]. White cement is also used
to manufacture white masonry cement meeting ASTM C 91
and white plastic cement meeting ASTM C 1328 (
PCA
1999
). White cement was first manufactured in the United
States in York, Pennsylvania in 1907. See
Farny (2001)
for
more information.
Air-Entraining Portland Cements
Specifications for three types of air-entraining portland
cement (Types IA, IIA, and IIIA) are given in ASTM C 150
and AASHTO M 85. They correspond in composition to
ASTM Types I, II, and III, respectively, except that small
quantities of air-entraining material are interground with
the clinker during manufacture. These cements produce
concrete with improved resistance to freezing and thawing.
Such concrete contains minute, well-distributed, and com-
pletely separated air bubbles. Air entrainment for most
concretes is achieved through the use of an air-entraining
admixture, rather than through the use of air-entraining
cements. Air-entraining cements are available only in
certain areas.
Fig. 2-18. White portland cement is used in white or light-colored architectural concrete, ranging from (left to right) terrazzo for
floors shown here with white cement and green granite aggregate (68923), to decorative and structural precast and cast-in-
place elements (68981), to building exteriors. The far right photograph shows a white precast concrete building housing the
ASTM Headquarters in West Conshohocken, Pennsylvania. Photo courtesy of ASTM.
