Blended cements may be used in concrete construction when specific properties or costs are required. Recent concern with energy conservation has prompted the use of by-product materials in portland cement concrete. Blended hydraulic cements are produced by intimately and uniformly blending two or more types of fine materials.
Portland Cement Type I Type I portland cement is a general-purpose cement suitable for all uses where the special properties of other types are not required. It is used in concrete that is not subject to aggressive exposures, such as sulfate attack from soil or water, or to an objectionable temperature rise due to heat generated by hydration. Its uses in concrete include pavements, floors, reinforced concrete buildings, bridges, railway structures, tanks and reservoirs, pipes, masonry units, and other pre-cast concrete products
Portland Cement Type II Type II portland cement is used where precaution against moderate sulfate attack is important, as in drainage structures where sulfate concentrations in ground waters are higher than normal but not unusually severe. Type II cement will usually generate less heat at a slower rate than Type I. This cement can be used in structures of considerable mass, such as large piers, and heavy abutments and retaining walls. Its use will reduce temperature rise, which is especially important when concrete is placed in warm weather.
Portland Cement Type III Type III portland cement provides high strengths at an early period, usually a week or less. It is chemically and physically similar to Type I cement, except that its particles have been ground finer. It is used when forms need to be removed as soon as possible or when the structure must be put into service quickly. In cold weather its use permits a reduction in the controlled curing period. Although richer mixes of Type I cement can be used to gain high early strength, Type III may provide it more satisfactorily and more economically.
Portland Cement Type IV Type IV portland cement is used where the rate and amount of heat generated from hydration must be minimized. It develops strength at a slower rate than other cement types. Type IV cement is intended for use in massive concrete structures, such as large gravity dams, where the temperature rise resulting from heat generated during hardening must be minimized.
Portland Cement Type V Type V portland cement is used only in concrete exposed to severe sulfate action - principally where soils or ground waters have a high sulfate content. It gains strength more slowly than Type I cement. The high sulfate resistance of Type V cement is attributed to a low tricalcium aluminate content. Sulfate resistance also increases with air entrainment and increasing cement contents (low water-cement ratios). Type V cement, like other portland cements, is not resistant to acids and other highly corrosive substances.
Portland Cement Type IP & P Portland-pozzolan cements are designated as Type IP or Type P. Type IP may be used for general construction and Type P is used in construction where high early strengths are not required. Type P is commonly used in massive structures such as piers, dams, and footings. These cements are manufactured by blending portland cement and a pozzolan. The pozzolan content of these cements is between 15% and 40% by weight. Laboratory tests indicate that performance of concrete made with Type IP cement as a group is similar to that of Type I cement concrete, however strengths through 28 days can be slightly lower for the Type IP than the Type I cement. Type IP may be designated as air-entraining, moderate sulfate resistant, or with moderate heat of hydration by adding the suffixes A, MS, or MH. Type P may be designated as low heat of hydration (LH), moderate sulfate resistant (MS), or air entraining (A).
Type I(PM) Pozzolan-modified portland cement. Type I(PM), is used in general concrete construction. The cement is manufactured by combining portland cement or portland blast-furnace slag cement and a fine pozzolan. This may be accomplished by either (1) blending portland cement with a pozzolan, (2) blending portland blast-furnace slag cement with a pozzolan. The pozzolan content is less than 15% by weight of the finished cement. Air-entrainment, moderate sulfate resistance, or moderate heat of hydration may be designated in any combination by adding the suffixes A, MS, or MH. An example of an air-entraining, moderate-heat-of-hydration Type I(PM) cement would be Type I(PM)-A(MH).
Type IS Portland blast-furnace slag cement, Type IS, may be used in general concrete construction. In producing these cements, granulated blast-furnace slag of selected quality is either interground with portland cement clinker, separately ground and blended with portland cement or produced with a combination of intergrinding and blending. The blast-furnace slag content of this cement is between 25% and 70% by weight. Air entrainment, moderate sulfate resistance, or moderate heat of hydration may be specified by adding the suffixes A, MS, or MH. For example, an air entraining portland blast-furnace slag cement that has moderate sulfate resistance would be designated as Type IS-A(MS).
Type S Slag cement, Type S, is used with portland cement in making concrete or with lime in making mortar, but is not used alone in structural concrete. Slag cement is manufactured by either (1) blending ground granulated blast-furnace slag and portland cement, (2) blending ground granulated blast-furnace slag and hydrated lime, or (3) a combination of blending ground granulated blast-furnace slag, portland cement, and hydrated lime. The minimum slag content is 70% of the weight of the slag cement. Air entrainment may be designated in a slag cement by adding the suffix A, for example, Type S-A.
Type I(SM) Slag-modified portland cement, Type I(SM), is used for general concrete construction. This cement is manufactured by blending portland cement and finely ground granulated blast-furnace slag. Slag is less than 25% of the weight of the finished cement. Type I(SM) may be designated with air entrainment, moderate sulfate resistance, or moderate heat of hydration by adding the suffixes A, MS, MH. An example would be Type I(SM)-A(MH) for an air entrained slag-modified portland cement with moderate heat of hydration.
Expansive Cements Expansive cement is a hydraulic cement that expands slightly during the early hardening period after setting. It must meet the requirements of ASTM C845 in which it is designated as Type E-1. Currently, three varieties of expansive cement are recognized and have been designated as K, M, and S, which are added as a suffix to the type. Type E-1(K) contains portland cement, anhydrous tetracalcium trialuminosulfate, calcium sulfate, and uncombined calcium oxide (lime). Type E-1(M) contains portland cement, calcium aluminate cement, and calcium sulfate. Type E-1(S) contains portland cement with a high tricalcium aluminate content and calcium sulfate.
When expansion is restrained, for example by reinforcement, expansive cement concrete (shrinkage-compensating concrete) can be used to (1) compensate for the volume decrease due to drying shrinkage, (2) induce tensile stress in reinforcement (post-tensioning), and (3) stabilize the long-term dimensions of post-tensioned concrete structures with respect to original design. One of the major advantages of using expansive cement in concrete is in the control and reduction of drying shrinkage cracks.
White Portland Cement 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, but 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 manganese oxides - the substance that gives cement its gray color. White portland cement is used primarily for architectural purposes such as precast curtain walls and facing panels, terrazzo surfaces, stucco, cement paint, tile grout, and decorative concrete. Its use is recommended wherever white or colored concrete or mortar is desired.
Oil-Well Cements Oil-well cements, used for sealing oil wells, are usually made from portland cement clinker or from blended hydraulic cements. Generally they must be slow-setting and resistant to high temperatures and pressures. The American Petroleum Institute Specifications for Materials and Testing for Well Cements (API Specification 10) includes requirements for nine classes of well cements (classes A through H and J). Each class is applicable for use at a certain range of well depths, temperatures, pressures, and sulfate environments. The petroleum industry also uses conventional type of portland cement with suitable cement-modifying admixtures. Expansive cements have also performed adequately as well cements.
Waterproofed Cements Waterproofed portland cement is usually made by adding a small amount of water-repellent additive such as stearate (sodium, aluminum, or other) to portland cement. Manufactured in wither white or gray color, it reduces capillary water transmission under little or no pressure but does not stop water-vapor transmission.
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