Final answer:
Type IA (option A) Portland cement contains a small quantity of an air-entraining agent. It combines Type I cement's general-purpose features with enhanced workability and durability necessary in freeze-thaw conditions.
Step-by-step explanation:
The type of Portland cement that has a small quantity of air-entraining agent interground during manufacture is Type IA. These specialized cements are formulated to include air-entraining properties, which contribute to better workability and durability, especially important in environments where freeze-thaw cycles are common.
Each type of Portland cement has a specific purpose:
- Type I is general-purpose cement.
- Type II provides moderate sulfate resistance.
- Type III delivers high early strength.
- Type IV offers low heat of hydration.
Therefore, for a cement that includes both the general-purpose characteristics of Type I Portland cement and the addition of an air-entraining agent, one would look for Type IA cement.