What Is Hydraulic Cement and What Is It Used For?

Patching small cracks with standard cement is difficult and time-consuming; however, hydraulic cement is an effective solution that can be applied relatively quickly to repair cracks and stop leaks in high-moisture conditions.

Hydraulic cement can fix damage in an area regularly exposed to water, like a concrete dock or the foundation of a home on the shore of a river, lake, or ocean. Due to its unique qualities in watery areas, hydraulic cement can greatly benefit home repair, renovation, and remodeling jobs. Learn more about what hydraulic cement is and its many uses.

What Is Hydraulic Cement?

Hydraulic cement is a liquid that rapidly dries and hardens when exposed to water. It can be used to fix cracks, patch chips, or even build tough, water-resistant structures like docks or dams.

Hydraulic cement has four primary ingredients: alite, belite, celite, and brownmillerite. Celite and brownmillerite keep the hydraulic cement in liquid form until it is ready. Alite and belite are binders that add strength and durability after it has hardened.

Why Is Hydraulic Cement Needed?

Standard cement is tough, durable, and long-lasting, so many people may question the need for hydraulic cement. However, this product more than meets expectations with a rapid setting time of just minutes for the hydraulic cement to solidify.

It dries and hardens quickly, making it ideal for projects around the home. Its water resistance and rapid chemical reaction speed increase its use in marine applications.

Hydraulic cement can be used above or below ground and is resistant to chemicals and heat. Apply this versatile product in wet or dry conditions. It fully cures when exposed to high moisture levels.

Hydraulic Cement Uses

Fixing Basement Wall Cracks

One of the more common uses of hydraulic cement is to fix minor cosmetic cracks in the basement wall. Small cracks can appear due to poor foundation drainage, water intrusion, or even the natural expansion and contraction of the concrete. Before patching the concrete, identify and fix the source of the problem.

Hydraulic cement dries and solidifies in minutes, so there isn’t much time to work the mixture into the cracks. To maximize the available working time, don’t add water to the mix until you are ready to begin.

Swimming Pool Repairs

The high level of water resistance makes hydraulic cement an excellent choice for wet and dry repairs, like fixing cracks or chips in the walls, floors, or deck of a concrete pool. Various issues, such as temperature fluctuations, seasonal frost heaves, earthquakes, or gradual setting, can cause cracks in swimming pools.

To repair the pool’s damage, drain and clean the affected surface to ensure the best adhesion possible. Unaddressed cracks and chips can lead to bigger problems. Water may leak out of the pool and into the surrounding soil, or chipped concrete could put swimmers at risk of being cut, so make swimming pool repairs as soon as possible.

Filling Fountain and Cistern Cracks

Fountains with below-ground tanks and cisterns can be affected by hydraulic pressure when the water inside presses against the walls. Over time, this force can cause cracks to form, leading to leaks and water contamination. Even fountains that have aboveground tanks can develop cracks during seasonal temperature changes.

Hydraulic cement can be used to fill and repair small cracks in the fountain or cistern to stop leaks, though this may not prevent further damage. It’s important to determine the cause of the issue and take action to resolve the problem beyond minor patches. If the issue persists, the fountain or cistern may need to be repaired or replaced by a professional.

Patching Chimneys

When the heat from the fire rises up the chimney, the clay flue liners will expand. When the fire dies out, and the air inside the chimney cools, the clay flue liners will contract with the changing temperature. This expansion and contraction can cause minor cracks to appear in the chimney.

Vertical cracks can be patched using hydraulic cement. These cracks are not a significant risk, but they should be repaired as soon as possible to prevent water from seeping through the chimney walls. However, it’s best to have a professional assess and fix horizontal chimney cracks, as these types of cracks can weaken the structure of the chimney, causing it to collapse.

Maintenance Hole Crack Repairs

Temperature changes are a common cause of maintenance hole cracks, though poor drainage can also contribute to this problem. When the water seeps into the gap between the maintenance hole and the soil, it gradually erodes the surrounding soil, causing it to shift, settle, and inevitably crack. Similarly, if the soil is not compacted properly at installation, the maintenance hole may shift or sink, causing the structure to crack.

Hydraulic cement shouldn’t be used for severe cracks, but it can effectively fix small cracks or chips in the structure. Its water resistance and fast drying time help ensure that the repair can be completed quickly without worrying too much about the existing moisture in the immediate environment.

Building Docks and Dams

Not all hydraulic cement can be used to build sturdy structures, like piers or retaining walls, but options are available with the appropriate level of strength and durability.

Low-heat hydration hydraulic cement is a great option for large structures like gravity dams. While this type of hydraulic cement has a long curing time, it gives off very little heat after being mixed with water, reducing the risk of cracks caused by thermal stress.

Similarly, high sulfate-resistant hydraulic cement has a long curing time, but this drawback is minor compared to the benefits. This type of hydraulic cement is used in piers, docks, and other structures exposed to seawater. The sulfate resistance reduces the risk of the seawater damaging the structure.

Mending Drainage Systems

A drainage system collects and disperses water in a way that reduces harm to the structure. Homes typically have a roof and gutter system that redirects the flow of water away from the foundation, but concrete drainage systems can also be buried underground to better control the flow of excess rain or meltwater.

When minor cracks occur, hydraulic cement can be used to fix the issue before it worsens. The hydraulic cement can seal the drainage line, preventing water from leaking into the soil. However, extensive damage may require more serious repairs or even lead to the replacement of the drainage line.

Sealing Masonry Structures

The rapid drying time and high level of water resistance make hydraulic cement an ideal option for sealing minor leaks in rock or other masonry material. In minutes, you can create a patch that will seal the structure and prevent moisture from seeping in, though this fix may not address the actual cause of the problem.

While hydraulic cement can be used for a temporary patch, this fix won’t last long if the pre-existing cause of the cracks in the masonry structure is not repaired. Hire a professional to assess the structure and make the necessary changes to resolve the problem. After fixing this issue, you can fill any cracks left behind with hydraulic cement.

Elevator Pit Patches

At the base of an elevator shaft is the elevator pit between the shaft’s lowest landing door and the ground at the bottom. Cracks can form in the elevator pit structure due to the floor, ground settling, or nearby equipment or vehicles.

If cracks are not patched, water can enter the pit, damaging the electrical equipment. Elevator repair professionals can use hydraulic cement to make quick fixes to the elevator pit. This will seal the shaft and prevent immediate damage, though it’s necessary to address the primary cause of the problem; otherwise, the situation could worsen.

Foundation Repair

Like basement repairs, hydraulic cement can be used to make minor foundation repairs by filling cracks or patching small holes or chips. However, due to the rapid drying time, it can be difficult to apply the hydraulic cement deep into a crack, so the DIYer must have everything ready to go before adding water and before it solidifies.

Hydraulic Cement Health and Safety Precautions

Hydraulic cement must be handled very carefully, and before applying it, you must wear necessary personal protective equipment (PPE), such as safety gloves, safety glasses, a mask or ventilator, closed-toe shoes, long pants, and a long-sleeve shirt. It’s important to avoid breathing in dust and prevent the cement dust from entering your eyes.