What Are The Basic Types Of Concrete Cement?

The goal of the investigation of cementitious materials should be to determine the suitability and availability of the various types of cement, pozzolan, and ground granulated blast-furnace (GGBF) slag for the structures involved and to select necessary options that may be needed with the available aggregates.

In cases where types or quantities of available cementitious materials are unusually limited, it may be necessary to consider altered structural shapes, changing the types of structure, altered construction sequence, imported aggregates, or other means of achieving an economical, serviceable structure.

The following types of cementitious material should be considered when selecting the materials:

(1) Portland cement. Portland cement and airentraining portland cement are described in American
Society for Testing and Materials (ASTM) C 150 (CRD-C 201).

(2) Blended hydraulic cement. The types of blended hydraulic cements are described in ASTM C 595
(CRD-C 203). ASTM Type I (PM) shall not be used; reference paragraph 4-3b(7) of this manual.

(3) Pozzolan. Coal fly ash and natural pozzolan are classified and defined in ASTM C 618 (CRD-C 255).

(4) GGBF slag. GGBF slag is described in ASTM C 989 (CRD-C 205).

(5) Other hydraulic cements.

(a) Expansive hydraulic cement. Expansive hydraulic cements are described in ASTM C 845 (CRD-C 204).

(b) Calcium-aluminate cement. Calcium-aluminate cements (also called high-alumina cement) are characterized by a rapid strength gain, high resistance to sulfate attack, resistance to acid attack, and resistance to high temperatures.

However, strength is lost at mildly elevated temperatures (e.g. >85 °F) in the presence of moisture. This negative feature makes calcium-aluminate cement impractical for most construction. It is used predominantly in the manufacture of refractory materials.

(c) Proprietary high early-strength cements. Cements are available that gain strength very rapidly, sometimes reaching compressive strengths of several thousand pounds per square in. (psi) in a few hours. These cements are marketed under various brand names. They are often not widely available, and the cost is much higher than portland cement. The extremely rapid strength gain makes them particularly suitable for pavement patching.

(6) Silica fume. Silica fume is a pozzolan. It is a byproduct of silicon and ferro-silicon alloy production.
Silica fume usually contains about 90 percent SiO2 in microscopic particles in the range of 0.1 to 0.2 μm. These properties make it an efficient filler as well as a very reactive pozzolan.

Silica fume combined with a high-range * water reducer is used in very high-strength concrete. Silica fume is described in ASTM C1240 (CRD-C270). Detailed information can be found in paragraphs 2-2d(5) and 10-10.*

(7) Air-entraining portland cement. Air-entraining portland cement is only allowed for use on structures covered by the specifications for "Concrete for Minor Structures," CW-03307. Air-entraining admixtures are used on all other Corps civil works structures since this allows the air content to be closely controlled and varied if need be.

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