The American Society for Testing and Materials (ASTM) recognizes five main categories of cement, but there is a plethora of variations across those categories to enable the manufacture of concrete that can withstand extra stress, water, chemical corrosion, and more. In this guide, we’ll be going into what cement is, as well as the ingredients and applications of the different types used in construction and civil engineering, from hydrophobic to more ordinary like OPC. At a glance:
Ordinary cement is a mixture of limestone, chalk, or marl and clay. It is manufactured by mixing the two ingredients, heating the mixture in a kiln, then grinding the resulting clinker to a fine powder. Though commonly confused with concrete, cement is actually an ingredient of concrete. Concrete is made up of a blend of cement, water, and stone and sand aggregates. You can find out more about the differences between these two materials in our article on concrete vs. cement(coming soon).
The different types of cement come from adding various ingredients and changing the proportions of ingredients. These additions and changes allow cement to be used in everything from general construction work to sulfate-resistant applications like sewage systems. Portland cement is only one of five basic types recognized by ASTM, the full list includes:
- Type 1 is ordinary Portland cement (OPC), which is a general-use material.
- Type 2 has moderate sulfate resistance, and its MH variant is moderately resistant to heat of hydration. It’s used in structures that will come into contact with sulfate in water or soil.
- Type 3 is an extra rapid hardening cement. Most concrete takes about a month to get to its full strength after it is poured; this becomes harder more quickly.
- Type 4 is a low heat cement that radiates less warmth as it sets and dries. It’s used for applications where too much heat is undesirable.
- Type 5 is highly sulfate resistant, used for contact with high alkaline soil and water.
Other varieties you may run into include:
- Types 1A, 2A, and 3A, which are variants of type 1, 2, and 3 cements. These types have air-entraining materials mixed in to make them resistant to moisture damage.
- Types IL (Portland-limestone), IS (Portland-slag cement), IT (ternary blended), and IP (Portland pozzolana) cement, which are hydraulic and have special properties. IS cement, commonly known as slag cement, includes granulated blast furnace slag and is often used to replace a portion of the portland cement going into the concrete.
- Type GU, HE, MS, HS, MH, and LH cements, whose names refer to their properties. GU stands for general use, HE for high early strength, and MS and HS for moderate and high sulfate resistance. Similarly, MH and LH refer to cement types with moderate and high heat of hydration.
Across all of these types, the most commonly varieties used include:
1. Ordinary Portland Cement (OPC)
Ordinary Portland Cement, also known simply as Portland cement or Type 1 cement, is widely used in construction work. It is made of Argillaceous or silicates of alumina (clay and shale) and calcareous or calcium carbonate (limestone, chalk, and marl). It is used for general construction purposes and most masonry work.
Though all portland cement is similar, eight types of cement are manufactured to meet different physical and chemical requirements for specific applications:
- Type I is a general purpose suitable for most uses.
- Type II is used for structures in water or soil containing moderate amounts of sulfate.
- Type II(MH) is a moderately sulfate resistant that also generates moderate heat during curing.
- Type III provides high strength at an early state, usually in a week or less.
- Type IV moderates heat generated by hydration that is used for massive concrete structures such as dams.
- Type V resists chemical attack by soil and water high in sulfates.
- Types IA, IIA, I(MH)A and IIIA are used to make air-entrained concrete. They have the same properties as Types I, II, II(MH), and III, except that they have small quantities of air-entraining materials combined with them.
White portland cement is made from the same raw materials as regular portland cement, but containing little or no iron or manganese, the substances that give conventional cement its gray color.
Some portland cements meet requirements for multiple cement types. For example, some are sold as Type I/II, which means that they meet all of the specification requirement in ASTM C150 (or AASHTO M 85) for both Type I and Type II.
2. White Cement
White cement is prepared from raw materials free from Iron oxide and is similar to Portland cement except for its white color. It is more expensive and is used for architectural purposes such as precast curtain walls, and interior and exterior decorative work such as facing slabs, floorings, ornamental concrete products and garden paths.
3. Water Repellent Cement
Water repellent or waterproof cement consists of ordinary or rapid hardening cement combined with a small percentage of metal stearates (such as Calcium or Aluminum) while it’s ground. It is used for the construction of structures that either retain water or will be in constant contact with water in some other way, such as tanks, reservoirs, retaining walls, swimming pools, dams, bridges, and piers.
4. Sulfate Resistant Cement (SRC)
This type has a very low heat of hydration, which means it does not generate much heat when reacting to water, and gains strength at a slower rate. It is used in applications where the soil has high levels of Sulphate/alkali containing compounds in the groundwater, sewage systems, piers and platforms on the coast. It reduces the risk of sulfate attack on concrete and is used in the construction of foundations where the soil has high sulfate or alkali content, as it also is often alkali-resistant. This includes places where the cement may come into contact with groundwater, sewage systems, or ocean water. It is also used for canals linings, culverts, retaining walls, and siphons.
5. Low Heat Cement
Low heat cement features a lower heat of hydration, and it needs less water to mix and set. This type is made from the same ingredients as portland cement, with some changes in the proportions of ingredients: it has lower amounts of tricalcium illuminate (around 5%), and higher amounts of dicalcium silicate (around 46%). Because it has high chemical corrosion resistance, it’s often used for floors and surfaces in chemical plants; due to its high strength and wear and rupture resistance, this is also used in dams, wind turbine feet, and large footings and raft slabs of concrete.
6. High Alumina Cement
High alumina cement is commonly used in marine and sewer construction, as well as in refractory applications. Created differently from other cements, this material is formed from baking ground up bauxite and lime in a kiln, then grinding the clinker again. High alumina cement has a low pH, making it highly chemical resistant, including to sulfuric acid.
7. Hydraulic Cement
Hydraulic cements, such as the IL, IS, IP, and IT types mentioned above, archetypes of hydrophobic cement. They are impervious to water and set quickly, leading to their use in underwater and waterproofing structural applications. It’s also quite strong and is corrosion and rust-resistant. Hydraulic cement does not, however, do well in colder temperatures.
8. Rapid Hardening Cement
Rapid hardening cement is comparable to Portland cement. It contains more tri-calcium silicate than Portland cement and is finer ground. This gives it greater strength development at an early stage than Portland cement. The strength after three days is almost the same as Portland cement’s after a week, with the same w/c ratio. The main benefit of using rapid hardening cement is that the formwork can be removed earlier and reused in other areas, lowering formwork’s overall cost. It is often used in prefabricated concrete construction and road work.
9. Expansive Cement
Expansive cement does not shrink during and after the time of hardening but expands slightly with time. It generally consists of Portland cement clinker with added calcium sulfate, and sometimes tricalcium aluminate. This type is used to help overcome shrinkage loss, and is often an essential part of sealing joints when used as expansion joint cement. Other applications for this type include grouting anchor bolts and prestressed concrete ducts.
10. Air Entraining Cement
Air-entraining cement creates concrete with billions of tiny air bubbles per cubic foot. When the water in concrete freezes due to low temperature, it expands. With this type, the air voids in concrete provide space for water to expand without cracking the concrete. The air bubbles take up between four and seven percent of the volume of the cement, but this varies as required by special conditions. This type is not a high strength cement. It is used in areas where the temperature is very low and where de-icing chemicals are applied.