Hydraulic cement is one of the materials a basement and foundation repair contractor may utilize to fill cracks in those areas of your home. Professionals also employ it in many other structural contexts as well. Learn all about hydraulic cement and its uses and applications with us below.
What is Hydraulic Cement?
Hydraulic cement is a material that starts as a liquid, but when applied to a structure and exposed to water, it rapidly dries and hardens. In fact, it can completely solidify within a matter of minutes, as opposed to the many days that average cement may take to dry. Hydraulic cement is used in construction and structural repair work due to this advantageous trait. On top of that, it’s also cost-effective and easy to work with.
Hydraulic cement itself is composed of a combination of substances, with four primary components of note. They are alite, belite, celite, and brownmillerite. Alite and belite give it its strength once it is hardened, while celite and brownmillerite help to keep it in its initial liquid state before it is used. There are other substances added to the mix in more minute amounts that improve the characteristics of hydraulic cement, such as its resistance to shrinking as it dries and its ability to be applied underwater.
How Hydraulic Cement Works
The aforementioned alite and belite are forms of the purer compounds known as tricalcium silicate and dicalcium silicate, respectively. They are named according to their chemical makeup. Tricalcium silicate is otherwise written as (CaO)3SiO2 and dicalcium silicate as (CaO)2SiO2. When water is added to these compounds, one of the main products of the reaction is calcium silicate hydrate. Calcium silicate hydrate creates multitudes of tiny fibers when it is formed within the hydraulic cement. These fibers are what toughen the cement overall and make it impervious to water.
The Uses and Types of Hydraulic Cement
People use hydraulic cement for several purposes, and there are different types of hydraulic cement to match them. We’ll list them in this section.
(Normal) Hydraulic Cement
This is the common form of hydraulic cement that lacks any situation-specific tweaks to its formula. It is used on a smaller scale for home, building, and structural repairs. It can fill and smooth over cracking on basements, floors, outdoor walkways, and around pipes. Professionals employ it to stop water from leaking in certain situations, since water cannot get past it once it has hardened.
White Hydraulic Cement
This type of hydraulic cement is identical to normal hydraulic cement utility-wise. However, it contains less magnesium and iron than regular hydraulic cement, which changes its color from gray to white. When the appearance of a building is meant to be white or lighter in hue, white hydraulic cement comes in handy since it won’t leave a dark smudge where it has been applied against a lighter wall or floor.
High Early Strength Hydraulic Cement
Although hydraulic cement becomes solid quickly, it can still take around a month for it to complete the curing process. During curing, the concrete needs to maintain a certain level of moisture and sit in a warm temperature range in order for it to harden to its full strength after setting. High early strength hydraulic cement reduces the curing time to about a week. It comes in handy when an edifice that it has been added to must be actively used soon after.
Moderate Heat of Hydration Hydraulic Cement
The reaction between hydraulic cement and water produces a significant amount of heat as a byproduct. Moderate heat of hydration hydraulic cement gives off less heat when it reacts. In some larger constructions, including sizeable foundations and high retaining walls, too much heat could end up leading to more cracks and weakening. This is of course counterproductive when you are trying to create a strong structure. Moderate heat of hydration hydraulic cement is thus used to make those large structures stable.
Low Heat of Hydration Hydraulic Cement
This form of hydraulic cement takes the concept of minimizing water reaction heat even further. There is a tradeoff, however. Low heat of hydration hydraulic cement requires a much longer curing time than other types of hydraulic cement. It is needed for building giant structures, such as gravity dams, which would not be able to remain secure if a lot of heat was generated as the cement solidified.
Moderate Sulfate-Resistant Hydraulic Cement
Sulfates are salts that may exist in the water or soil found outside. When they are near concrete, they can react with it in a way that causes the concrete to expand unevenly, which in turn leads to warping and cracking. Moderate sulfate resistant hydraulic cement remains sturdy around sulfates because it has chlorides added into it. This hydraulic cement is useful for structures that are built along coastlines, since they may come into contact with more water than the average structure.
High Sulfate-Resistant Hydraulic Cement
High sulfate resistant hydraulic cement is affected by sulfates even less than its moderate variant. Similar to low heat of hydration hydraulic cement, it gains this advantage in exchange for gaining a longer curing time. A structure that will be exposed to sulfates frequently and in high quantities, such as a dock, can benefit from being constructed with this type of hydraulic cement.
Hydraulic Cement in Basement/Foundation Repair
Now, let’s zero in on how hydraulic cement is used for basement and foundation repair.
Proper Use in Exterior Crack Repair
Hydraulic cement comes in handy when basement and foundation cracks are repaired from the outside of the house, as may be the preference of a homeowner. In such a scenario, professionals must dig up the earth around the cracked area and then clean off the excess dirt from the foundation wall. After this, they can plug up the cavities with hydraulic cement. Over this, black tar is applied and a vapor barrier is installed to waterproof that portion of the foundation. To finish, the soil is put back.
You may choose exterior crack repair when the crack in question is inaccessible from the inside of the basement, either because it does not appear visible there, or because there is an obstacle like a furnace in the way.
Limitations for Basement/Foundation Repair
Though it works in some situations, hydraulic cement is not a panacea for fixing your foundation and basement. Cracks often manifest in your foundation or basement because of the pressure water and/or soil exerted on your house. In this case, simply patching up those voids with hydraulic cement will not solve the problem permanently, and new cracks can still form while old ones can reappear and get bigger.
Furthermore, some contractors install bleeder tubes and use hydraulic cement to fill in the channels in the foundation that they have cut to make space for the tubes. Bleeder tubes are meant to help the foundation drain out water by letting it flow out underneath them. However, they end up weakening the foundation’s structural integrity since chunks of it are excised from its bottom—the very part that the rest of the home rests on. Large cracks then arise from the bleeder tube setup. Therefore, you should avoid this foundation repair method and application of hydraulic cement.
Your greater grasp of hydraulic cement and its uses and applications can help you understand what you want more clearly when speaking with contractors. Call The Real Seal today if you want to hire a reliable company for basement waterproofing in the Chicago area so you can have your foundation and basement cracks mended.
Know more about – The Importance of Basement Inspections
38 Responses
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I’m questioning whether to use hydraulic cement as a topping mix around my pool coping . It’s only to feather 3/8 “ or less down to zero about 6” wide, but it’s superior hardness makes me think it might not be adhering well so thin. What’s your take?
Hi Nick! A pool coping is the finishing touch on your pool, and we would suggest using something more aesthetically pleasing. It can be difficult to get a smooth surface with hydraulic cement. Best to consult with a pool construction expert to find the best solution for that.
we have a good size crack in our inground pool, it seems ground water and perhaps a shift due to earth tremors have created these cracks. is it appropriate to use hydraulic cement to repair? The pool holds approx 8,000 gallons water and at the deep end it is 4.5 ft. this is the end where the cracks are.
Hi Lilly,
Before repairing the cracks, you should get in a reputable contractor in order to stop the settlement of the pool. This can be done numerous ways depending on the issue, but should come first before the cracks. Once done, we would suggest an epoxy injection for those cracks to ensure a strong repair.
I’ve got a new shotcrete pond and it has many crevices from 1/2 in. to 1 in. deep, will hydraulic cement fill these crevices to make it smooth enough to apply an epoxy coating?
Hi Michael,
You will need to check the type of epoxy you are using. For an epoxy coating, typically there are different kind of fills that contractors will use that bonds better with epoxy.
Dose that include any type of sealant?
There is a special sealant to apply if you are going to use an epoxy sealant over it. I would consult with the epoxy sealant company/product to get the specifics for that product.
I have a buried 1200 gl water tank that has appropriately a 1/16th of an inch hole near the bottom where a root had penetrated and may have a slight crack as well. Which of these products would you recommend to repair it?
Hi Susan!
Unfortunately we do not repair water tanks so wouldn’t be the best people to help you with that repair. Especially with all the pressure of the tank, it’s important to consult a professional who is familiar with these situations to get you pointed in the right direction. Hydraulic Cement would certainly not be a good solution for this application.
I own a 120 year old Victorian with brick columns in my basement holding up the house. The bricks are losing mortar and need repointing. Can I use hydraulic cement to repair?
Hi Richard,
For this application, we would recommend removing the brick columns and replacing with steel columns. This will provide better, longer-lasting support.
If you were to just repair, you would want mortar to repair it with, not Hydraulic Cement. Mortar will provide better support and strength.
I want to seal crack in basement wall and floor cracks, will hydraulic cement will it work and will color be grey?
Hi Lil!
For basement wall and floor cracks, we do not recommend hydraulic cement ONLY. It can be used as a filler, but an epoxy needs to fill the wall cracks in order to stop them for leaking.
For the floor cracks, you can simply use a silicone caulking to seal them from radon gasses and humidity. If the floor cracks are actively seeping water, you’ll need to install a Drain Tile System in order to keep the basement dry.
Does all that makes sense?
how to smoother out hydraulic cement, Sand the Surface? or then using joint compound on the hydraulic cement? because I will paint smoother over there.
thanks.
Hi jane!
Smoothing out hydraulic cement is mostly going to come down to how you mix it. The more water you put in the mix (not too much!) the more workable the hydraulic cement will be. You can typically paint hydraulic cement without much issue, but if you want it the consistency of drywall you’ll end up disappointed. You can try the joint compound to make it smoother.
Thanks Austin Werner, I’ve noticed that it seems like most of water stop products, will put joint compound on them are not recommended?
Hi Jane!
Yes, joint compound should stick to hydraulic cement.
Hi, Austin Werner，I have another question,
Cause Hydraulic Cement has a working time of just 3-10 minutes.
I am thinking that it is impossible to make the wall surface smooth at once. so can I apply Hydraulic Cement second layer as a filling/smoothing wall after the first layer ?
If yes, how long should take to apply the second layer after the first Hydraulic Cement layer?
If no, can I use general cement as second layer filling/smoothing on Hydraulic Cement?
thanks
Hi Jane! You can actually get a smooth surface with the first coat. You can adjust the working time of the hydraulic cement by adding more water to make it set up slower. This will allow you more time to get a smooth surface.
Because the place I need to fill is in the corner of the basement stairs
Of course. If you adjust the mixture by adding water, you can get the consistency you want with the hydraulic cement.
Dear Mr. Werner,
I must have a polybutylene water line replaced. The contractor does not want to use the existing basement wall penetration, which is 7′ below grade. He wants to cap that one off from the inside.
He wants to run the new copper water line through a new hole drilled through the concrete basement wall about 3′ below grade. The house is 27 years old. The only water proofing around the pipe will be a sleeve and hydraulic patch. Is this adequate to prevent water seepage through the basement wall during a heavy rain?
Thank you.
Hi, SL!
So the main reason the plumber doesn’t want to use the 7′ hole below grade is the extra labor for removing dirt. That would increase your cost as well. It is ok to do a new hole, as long as it is below the frost line in your area, in order to accomplish this.
It is NOT ok to just do a hydraulic patch. That will certainly leak, and we fix them all the time. The repair that needs to be done after the plumber is a Polyurethane Injection around that water line. The plumber will not be able to handle this. You will need to hire a waterproofing company to come perform the Polyurethane Injection. That repair should come with a Lifetime Warranty and will be adequate to stop the seepage through those holes.
Hi-
I would like to create a small burm maybe 2″ x 2″ x 4′ to divert water away from a hole. Will Hydraulic cement be a good material to use on the concrete?
Hello!
It could work, but for this application it may not hold up as long as 4000 psi concrete. With it being up against water all the time, the 4000 psi concrete would be a better option.
I have a crack line on my basement floor that water seep through. The crack line isn’t wide but water is still seeping through. If I use some hydraulic cement to cover the crack line. What do I use to go over the hydraulic cement once it dries?
Hi Lorin,
We would not recommend using hydraulic cement for that use. You have a underlying Hydrostatic Pressure issue. This is causing the water to come up through the floor. The best solution here is to install a Drain Tile System. That will ensure no water comes in through those cracks.
Great insights into hydraulic cement! It’s fascinating to learn about its various applications in construction and its benefits over traditional cement. I never knew it could set underwater—definitely a game changer for projects near water. Thanks for sharing!
Always happy to help!
Great insights on hydraulic cement! I had no idea about its versatility in various construction applications. It’s fascinating how it can set underwater and is used in so many projects. Thanks for sharing this valuable information!
You bet, happy to help!
Great post! I found the information on the various applications of hydraulic cement really helpful. It’s fascinating to see how versatile it is in construction and repair projects. I especially appreciated the tips on proper mixing and curing techniques. Looking forward to trying it out on my next DIY project!
Happy to help!
This post on hydraulic cement is incredibly informative! I had no idea about its versatility and various applications in construction. The examples you provided really helped to clarify its benefits, especially in wet environments. Thanks for sharing such valuable insights!
You’re very welcome!