Concrete

Types of Cement Explained

Four portland types, one retired type, and the blended cements that replaced it.

Reviewed July 2026

The types of cement you will meet on a jobsite are mostly variations on one product: portland cement, made to the ASTM C150 standard. Four basic types are in current use, Type I, Type II, Type III, and Type V, and each one exists to solve a specific problem, whether that is sulfate attack from the soil or the need for strength in days rather than weeks. A separate family of blended cements, made to ASTM C595, mixes portland cement with other materials. Here is how the whole set fits together.

All of them are hydraulic cements

The American Cement Association describes portland and blended cements as hydraulic cements based on hydraulic calcium silicate. Hydraulic cement is the broader term: it means a material that forms solid hydrates when it reacts with water, and that can do so even under water. That is the property separating cement from something that merely dries. It is also why the water-to-cement ratio governs strength, as covered in the concrete mix ratio guide.

The four current ASTM C150 portland cements

Type I is the default and suits any job where the special properties of another type are not needed. Type III delivers design strength in a matter of days rather than the usual 28, which buys you early form removal, faster paving, and a shorter curing period in cold weather. Type II and Type V both address sulfate attack, at moderate and high levels respectively; Type V gains strength more slowly than Type I as part of that bargain.

You will notice Type IV is missing. It was the low heat of hydration cement, the kind used in Hoover Dam in 1935 to keep a massive pour from cooking itself. Broader use of moderate and low heat cements has since been replaced by other strategies, chiefly partial replacement of cement with supplementary cementitious materials such as fly ash. Treat Type IV as history rather than a current product.

What sulfate resistance actually resists

Sulfates in soil or groundwater enter the concrete and react with hydrated C3A phases, and the result is expansion, scaling, and cracking. Some sulfate compounds, magnesium sulfate among them, attack the calcium silicate hydrate directly. Moderate sulfate resistant cement handles soils, seawater, and groundwater where sulfate levels are higher than normal but not severe; high sulfate resistant cement is for severe exposure.

Two honest caveats sit alongside that. Even high sulfate resistant concrete cannot survive a severe sulfate exposure if it was mixed at a high water-cementitious materials ratio, so the cement type never rescues a bad mix. And no portland or blended cement resists acids or other highly corrosive substances at all. Sulfate resistance is not chemical resistance in general.

Seawater is the interesting case. It carries plenty of sulfates but also chlorides, and the chlorides inhibit the expansive reaction that characterizes sulfate attack. A marine environment counts as a moderate sulfate exposure class. The chlorides create a different problem instead, corroding embedded steel, which is the whole argument for fiberglass rebar in coastal work.

Air-entraining and blended cements

ASTM C150 also specifies three air-entraining portland cements, Types IA, IIA, and IIIA. They match Types I, II, and III in composition, except that small quantities of air-entraining additions are interground with the clinker during manufacture. Entrained air, meaning fine, well-distributed, separated bubbles, improves durability against freeze-thaw cycles. Most concrete gets its air from an admixture added at the batch plant rather than from these cements, so check local availability before specifying them.

Blended hydraulic cements are made to ASTM C595 by intergrinding or blending two or more fine materials: portland cement, limestone, slag cement, coal ash, silica fume, calcined clay, and other pozzolans. They carry designations such as IL, IP, and IS. A third standard, ASTM C1157, sidesteps composition entirely and classifies hydraulic cements by performance, using labels like GU for general use, HE for high early strength, and HS for high sulfate resistance.

What to actually order

For most general construction, a general-purpose cement is the right answer, and in recent years the most widely available cement in the United States has been Type I/II, which meets the requirements of both types at once. Reach for Type III when the schedule demands early strength, and for Type II or Type V when a soil report tells you sulfates are present. Match the cement to the exposure the concrete will actually see, then get the water-cement ratio right, because the mix will undo a good cement long before the cement fails you.

Source: American Cement Association, Types of Cement.

Materials Review is an independent educational resource. It is not affiliated with Pittsburg State University or the former Kansas Polymer Research Center, and it is not a substitute for a licensed engineer. Confirm structural, safety, and code questions with a qualified professional before acting.