Five types of Portland cement are manufactured. Each cement has its own specific purpose. Type I and II are generally used in mortar while the other types are usually used for mixing concrete.
Type I cement is general-purpose cement that is used most often by masons. It may be used in pavements, sidewalks, reinforced concrete bridges and masonry mortar.
Type II cement, referred to as modified Portland cement, generates less heat and at a slower rate than Type I, though it does have better resistance to sulfate than Type I. It is usually specified for use with large piers, heavy abutments and heavy retaining walls.
Type Ill cement, also called high early strength, Portland cement, requires as much time to set as Type I though it achieves its full strength much faster. It is recommended when high strength is needed in one to three day sand in cold weather when protection from freezing is critical.
Type IV or low-heat Portland cement is special cement for use with the amount and rate of heat generated must be kept at a minimum. It is critical to hold the temperature down to ensure
that the concrete cures properly. Since the concrete does cure slowly, strength also develops at a slower rate. Too much heat in the hardening process causes a defective or weak concrete. Low-heat concrete is used in mass concrete such as dams and large bridges.
Type V or sulfate-resistant Portland cement is special cement used only in concrete exposed to severe sulfate action. It is used principally in some western states, which have soils or ground water of high sulfate content. It gains strength at a slower rate than normal Type I cement.
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