Civil Engineering Reference
In-Depth Information
Na
2
O are not permitted as they promote expansion with certain types of
aggregates.
ASTM C-150 describes five major types of portland cement. They are:
• Normal—Type I—is used for most purposes and when
special properties specified for any other type are not
required
• Moderate Sulfate Resistant or Moderate Heat of Hydra-
tion—Type II
• High Early Strength—Type III
• Low Heat—Type IV
• Sulfate Resisting—Type V
The general composition, fineness, and compressive strength characteris-
tics of these cements are shown in Table 1.
[1][31]
Portland cement may be blended with other ingredients to form
blended hydraulic cements. ASTM C-595 covers five kinds of blended
hydraulic cements. The portland blast furnace slag cement consists of an
intimately ground mixture of portland cement clinker and granulated blast
furnace slag or an intimate and uniform blend of portland cement and fine
granulated blast furnace slag in which the slag constituent is within
specified limits. The portland-pozzolan cement consists of an intimate and
uniform blend of portland cement or portland blast furnace slag cement and
fine pozzolan. The slag cement consists mostly of granulated blast furnace
slag and hydrated lime. The others include pozzolan-modified portland
cement (pozzolan < 15%) and slag-modified portland cement (slag < 25%).
3.0
INDIVIDUAL CEMENT COMPOUNDS
3.1
Tricalcium Silicate
Knowledge of the hydration behavior of individual cement com-
pounds and their mixtures forms a basis for interpreting the complex
reactions that occur when portland cement is hydrated under various
conditions. For a given particle size distribution and water:solid ratio,
tricalcium silicate and alite harden in a manner similar to that of a typical
portland cement.
