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What is Hydraulic Cement?

Adam Hill
Adam Hill

The oldest cements are as old as construction itself, and as civilization has advanced and its needs have changed, so has cement. One type of modern cement is hydraulic cement. Around the start of the Industrial Revolution, hydraulic cement was developed as a way to meet the changing needs of the construction industry and the people it served. Hydraulic cement refers to any cement that will set and harden after being combined with water. Most construction cements today are hydraulic.

When a dry hydraulic cement is mixed with water, certain chemical reactions take place in the mixture. These reactions form chemical compounds which contain water, and the formation of these compounds causes the mixture to harden. Because of the nature of the compounds formed in these reactions, they are insoluble in water. This means that the hardened cement will retain its strength and hardness even if immersed in water. This makes it ideal for brick buildings in wet climates, harbor structures that are in contact with sea water, and many other applications.

A man smoothing out hydraulic cement on a basement floor.
A man smoothing out hydraulic cement on a basement floor.

It is important to distinguish cement from concrete. Although these terms are often used interchangeably outside the construction industry, they refer to different products. For example, the most common type of hydraulic cement is called Portland cement. Portland cement is most commonly used in the production of concrete, which contains cement, sand, gravel, and water.

Portland cement is most commonly used in the production of concrete, which contains cement, sand, gravel, and water.
Portland cement is most commonly used in the production of concrete, which contains cement, sand, gravel, and water.

Cement itself is produced by heating limestone with small amounts of other ingredients such as clay. The mixture is brought to a high temperature in a kiln, and the hard substance which results is referred to as “clinker.” Clinker is then ground up into a powder along with a small amount of gypsum. The finished product is ordinary Portland cement. This basic mixture is varied to make a wide variety of Portland cements, suited to many specific applications.

Most construction cements used today are hydraulic, meaning they will set after being mixed with water.
Most construction cements used today are hydraulic, meaning they will set after being mixed with water.

One common application for special hydraulic cement blends is repairing cracks and leaks. Certain types of cement contain an ingredient which causes the cement to expand as it sets, filling in leaks and holes in concrete or other structural materials. There is often a need for this type of repair work because of the fact that ordinary Portland cement shrinks slightly as it dries. Places like basements in areas with wet climates are especially prone to leaks because of this. These special blends can be hard for novices to work with, though, because once mixed, the material only remains workable for 10 to 15 minutes.

Discussion Comments

gator77

similar to "anon101537", can a hydraulic cement hole patch be drilled?

anon956003

Where did hydraulic cement come from?

anon285604

Can hydraulic cement be used to cover old countertops such as cultured marble or laminate? We need an inexpensive way to freshen up our countertops and have a rustic, textured look.

anon101537

someone drilled too large a hole for my hurricane shutters and they is no other area to drill, if we use hydraulic cement to patch the holes. Will the hydraulic cement after curing be able to hold the anchors and screws for the hurricane shutters?

win199

@BelugaWhale - Using hydraulic cement is actually easier than other cements. Most companies that have a cement truck or cement mixer have a hydraulic mix in them. Personally, I think they work better simply because of the fact that you mentioned: they have a rock mix in them that allows the cement to come out even.

Working with a cement mix that's not hydraulic can be tricky because it's already been moistened. You have less time to get it set in the spot you want where working with a hydraulic mix allows you to work at your own pace and add more or less depending on the job's needs.

BelugaWhale

@Kamchatka - Many hydraulic cement mixes can be found at do it yourself or home improvement stores and often come with a pebble mixture included within the actual mix. The pebbles or rocks within the mix weigh down to the bottom once it's been set and helps to create a smooth surface, which is exactly what you should be looking for when leveling.

Kamchatka

Hydraulic cement is used for pretty much everything from highways to storage shed foundations. This is useful knowledge because if you're looking to create your own foundation, you know you can rely on a hydraulic cement.

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    • A man smoothing out hydraulic cement on a basement floor.
      By: Lilyana Vynogradova
      A man smoothing out hydraulic cement on a basement floor.
    • Portland cement is most commonly used in the production of concrete, which contains cement, sand, gravel, and water.
      By: Christian Delbert
      Portland cement is most commonly used in the production of concrete, which contains cement, sand, gravel, and water.
    • Most construction cements used today are hydraulic, meaning they will set after being mixed with water.
      By: Kadmy
      Most construction cements used today are hydraulic, meaning they will set after being mixed with water.
    • Cement powder is commonly made of lime and clay and is a key ingredient of concrete.
      By: Yali Shi
      Cement powder is commonly made of lime and clay and is a key ingredient of concrete.
    • Hydraulic cement is commonly used for sidewalks, driveways and other paving and construction needs.
      By: podsolnykh
      Hydraulic cement is commonly used for sidewalks, driveways and other paving and construction needs.