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What is Hydraulic Cement? 9 Distinct Uses for This Versatile Material

Hydraulic cement is a type of powdery dry cement that sets and hardens after interacting with water. Its initial invention dates back to the Roman Empire, and it continues to be extensively used in construction and repair projects today. Hydraulic cement is a combination of additives, which work together to decrease its setting time — meaning it can set even in wet conditions. 

An additional benefit of hydraulic cement is that, unlike regular concrete mixtures, hydraulic cement does not shrink upon drying, but may instead expand slightly. This article will look at what hydraulic cement is, how it’s used and why it’s so important to the construction industry.

What is Hydraulic Cement?

Hydraulic cement is a type of cement that sets and hardens when mixed with water. It is used in many construction and repair projects, from fixing cracks in sidewalks to lining the bottom of ponds. It usually consists of a fine powder made from limestone, clay or gypsum. 

When mixed with water, the powder forms a paste that can be spread or sprayed onto surfaces. The water activates a chemical reaction that causes the paste to harden and bind to the surface. 

Why is it Necessary?

Hydraulic cement is more durable than regular cement and can be used in wet or dry conditions, as well as above or below ground. It is also resistant to chemicals and heat. It can be applied underwater and will cure even when exposed to high levels of moisture. Whether you’re patching up a crack in your sidewalk or repairing a leaky basement wall, hydraulic cement is an essential tool for any home improvement project.

Understanding Cement vs. Concrete

Although cement and concrete are terms often used interchangeably, they differ greatly. Cement is a fine powder made from limestone, clay and gypsum that hardens when mixed with water and other ingredients. Concrete is created by mixing hydraulic cement, water and aggregate, such as sand or gravel.

The proportions of these ingredients are important because they determine the strength and durability of the finished product. Hydraulic cement sets and hardens by reaction with water. This type of cement is often used in underwater projects because it will not wash away.

9 Uses for Hydraulic Cement

Most cracks are caused by settling, which occurs naturally over time. However, some can be due to poor construction techniques. Either way, they need to be repaired as quickly as possible to avoid further damage from water intrusion, pest infiltration or further deterioration and widening of the initial crack. Hydraulic cement is the go-to product to affect these repairs.

1. Foundations

What is Hydraulic Cement? 9 Distinct Uses of This Material


Cracks can form in your foundation for various reasons. The ground settles naturally over time, and this process causes the surrounding foundations to shift. Additionally, water leakage is a common occurrence when the temperature changes. Once cracks start appearing, they must be treated immediately. Otherwise, the problem will only continue to grow worse.

2. Basement Walls

Basement Walls


Similar to cracks caused by settling in your foundation, as dirt under the footings shift, the concrete or poured basement walls can move slightly, causing hairline cracks that need to be repaired. If water seeps into foundation walls made of concrete, it will weaken the material over time and make it more susceptible to cracking. In the case of concrete blocks, the mortar joints can separate and eventually result in structural issues.

3. Swimming Pools

Swimming Pools


Cracks in swimming pools are caused by many factors. The most common cause is hydraulic pressure. This happens when the water in the pool is pushed against the walls of the pool by the weight of the water. The pressure can cause the walls to crack or break. 

Another common cause of cracks is when the ground underneath the pool shifts or settles. This can happen due to a variety of reasons, including earthquakes, heavy rains or even just slow, gradual settling. Whatever the cause, it’s important to repair cracks as soon as possible, as they can lead to further damage and leaks if left unaddressed.

4. Chimneys



Clay flue liners expand and contract as they heat up and cool down, which can cause cracks. Unfortunately, there is little you can do to prevent it from happening. However, there are methods for repairing the cracks so that they do not get worse. The first step is to determine the sort of crack. The most frequent variety is vertical fractures that run downward from the top of the chimney.

These usually don’t pose a structural danger, but should be repaired in order to prevent water from seeping in. Horizontal cracks are less common and can run along the length of the flue liner or near the base of the chimney. These types of cracks are more serious because they weaken the structure of the chimney and can cause it to collapse.

The best way to repair both vertical and horizontal cracks is by using hydraulic cement. This type of cement expands as it dries, filling in the crack and creating a tight seal.

5. Cisterns and Fountains

Cisterns and Fountains


Like basement walls and pools, cisterns are subject to hydraulic pressure, as the water inside presses against the walls, causing cracks over time. These cracks can lead to leaks and also allow contamination into the cistern, which may affect the quality of the water contained in it. 

If fountains have a base tank below ground, they are also susceptible to the same dangers as the cistern. The concrete fountain above ground could crack from temperature swings throughout the seasons, eventually leading to malfunction or complete stoppage of the water flow.

6. Drainage Systems

Drainage Systems


Drainage systems certainly have a lifespan, the length of which depends on the material used for the piping. All pipes in contact with exterior forces will eventually leak, but black polyethylene, for example, will deteriorate faster, especially with the help of infringing tree roots. According to The Spruce, tree roots cannot penetrate metal pipes, but weaknesses that develop in metal pipes over time can be infiltrated by tree roots, causing blockage and/​or leaks.

It’s important then to make sure the concrete used in drainage systems is hydraulic concrete to protect from the eventuality of leaks, which ensures that only pipes need be replaced, not the entire system. If inferior concrete is used, water leakage from faulty pipes can cause cracking, leading to unsightly crack development that will lead to an entire system replacement.

7. Elevator Pits

Elevator Pits


Causes of cracks in an elevator pit can be due to the settling of the floor or ground around the pit and damage from equipment or vehicles operating nearby. Once a crack appears, it is important to repair it as soon as possible. Otherwise, water can enter the pit and cause further damage to the electrical or hydraulic equipment located in the space. 

8. Manholes



There are many causes of cracks in manholes. One common cause is the expansion and contraction of the ground due to temperature changes. As the ground expands in the heat, it puts pressure on the manhole walls and can cause them to crack. In cold weather, the ground contracts and can also cause cracking. Another common cause of cracks is poor drainage. When water drains around the manhole, it can erode the soil, causing the manhole to settle and crack.

Poorly compacted soil can also cause cracks, as well as subsidence (sinking) of the manhole. In some cases, tree roots can grow into cracks in the manhole and cause them to widen. Finally, traffic passing over a manhole can also cause it to crack. The weight of vehicles causes vibrations that can damage the manhole walls.

9. Sealing in Masonry Structures

Sealing in Masonry Structures


Basically, anything constructed of rock or masonry has the potential to develop leaks. Both materials are strong, but cannot avoid the damage caused by time and the elements. The best prevention is to regularly inspect these structures to detect cracks before they become leaks.

The Best Hydraulic Cement Product for a Fast, Watertight Seal

The Best Hydraulic Cement Product for a Fast, Watertight Seal


When it comes to sealing a leak in concrete or masonry, time is of the essence. You need it to operate quickly in the most demanding situations and stop the leak. 

DRYLOK’s Fast Plug Hydraulic Cement creates a watertight seal in three to five minutes and works efficiently even on active leaks, making it ideal for stopping leaks and sealing cracks or damages like the ones listed above.

In addition:

  • It comes in an easy mix, powder formula.

  • It sets quickly — the temperature of the water or admix controls the set time.

  • It is perfect for use in most waterproofing projects to seal cracks, floor-wall joints and utility entrance holes.

Find the Best Concrete and Masonry Products with DRYLOK

If you’re looking for the best hydraulic cement to seal cracks in concrete or masonry structures or any other waterproofing products, look no further than DRYLOK. We have a wide variety of products to suit your needs, and our experienced staff is always happy to help you find the right product for your project. 

Contact us today to learn more about our hydraulic cement and other waterproofing products!