Additive to concrete for waterproofing the foundation: main types and their analogues, purpose and principle of operation

Welcome to "All about Concrete," where we will delve into the realm of building supplies and methods. Today, we’ll discuss concrete waterproofing additives, a crucial component of building foundations. Any structure’s longevity and integrity depend on an understanding of these additives.

A staple of construction, concrete is renowned for its sturdiness and strength. It may, however, be vulnerable to water intrusion, particularly in foundations. During construction, additives made expressly for waterproofing are added to the concrete mixture to address this problem.

Additives fall into several categories when it comes to waterproofing foundations. Integral waterproofing additives are a typical kind. Prior to pouring, these additives are directly added to the concrete mixture. They function by making the concrete’s capillary pores smaller and less connected, which strengthens the material’s resistance to water infiltration.

The additive known as crystalline waterproofing is another kind. When this technology is exposed to water, crystals begin to form within the concrete matrix. These crystals effectively stop water from penetrating the concrete by obstructing its pores and microcracks.

In addition, surface treatments are employed as waterproofing additives. These coatings create a water-repellent barrier when applied to the exterior of concrete that has hardened. They offer an extra layer of defense against water intrusion and can take the shape of sealants, coatings, or membranes.

It is simple to understand why these additives are being used: to prevent water damage to the foundation. Over time, water intrusion can erode concrete, create cracks, and result in structural problems. Builds can greatly increase the foundation’s lifespan by incorporating waterproofing additives.

Depending on the kind of additive being used, there are different operating principles. Integral additives change the physical structure of the concrete from the inside out to increase its water resistance. While surface treatments physically prevent water from penetrating the concrete, crystalline additives react chemically with water to form a protective barrier.

In conclusion, anyone working in the construction industry needs to understand the different kinds of waterproofing additives and their underlying principles. The longevity and upkeep of your building’s foundation can be greatly impacted by the additive you choose, whether you’re a professional in the construction industry or a homeowner organizing a foundation project. Keep checking back to "All about Concrete" for more insights into concrete and its uses.

Additive types	Main analogues
Waterproofing agents	Water-repellent admixtures
Purpose	Prevent water penetration into foundation
Principle	Create a barrier against moisture

Purpose and principle of operation

Special additives can reduce water absorption rates and significantly improve the waterproofing properties of concrete mortar. The monolith’s porosity can be significantly reduced with the aid of additives. Filling cavities, fissures, and capillaries can be done with special crystals that are insoluble in water; the more moisture the stone absorbs, the more actively these crystals will expand.

As a result, moisture is forced out of the monolith and keeps out. This keeps the hardened concrete from becoming more brittle by preventing free lime from being washed out. Owing to the chemical processes occurring within the stone, the material’s structure becomes denser and stronger, and the pores shrink in size and become locked, resulting in a perfectly symmetrical monolith. Macropores shrink in quantity and become spheres up to 0.1 millimeters in size. However, concrete’s vapor permeability doesn’t change.

Concrete waterproofing additives can also function on a different principle: they coat the pore walls with byproducts of the cement-specific substances reaction, which form tiny spheres and form a coating or layer that, when surface tension acts, just drives moisture out of the concrete.

Additionally, reagents that interact with the cement in the mixture but maintain the characteristics of a mechanical impurity can be used as a waterproofing additive for concrete. Additives minimize shrinkage by creating ideal conditions for uniform moisture evaporation as the monolith becomes stronger.

There may be a decrease in the number of pores and an increase in airborne particles due to the solution’s increased mobility. In this instance, the mixture releases heat at a slower rate, the solution sets and hardens more slowly, hydration also slows down correspondingly, and the monolith’s strength clearly declines (this may be significant in some circumstances).

Concrete porosity

Any concrete solution implies the appearance of some air voids, or pores, during pouring, regardless of how it is mixed or composed. The strength of the monolith decreases with the number of voids. The solution is immediately tamped and vibrated after pouring to reduce the number of pores; this does not completely eliminate the voids but greatly enhances the properties.

When concrete is exposed to moisture, its pores become the primary source of damage. Water seeps into the pores, where it freezes and expands during the winter, simultaneously destroying the material. There are visible flaws like chips, cracks, and deformations that could eventually cause the structure to collapse.

Advantages and disadvantages

These days, concrete waterproofing additives are used everywhere. They must be used precisely as directed, taking into account the technology and proportions. It is best to research the benefits and drawbacks of adding additives to the concrete solution before settling on a particular brand of mixture.

• Simplification of construction work, improving the quality of the final structures, elements with the ability not to use waterproofing materials
• Increasing the service life of the monolith
• Increasing the level of water resistance to W20
• The frost resistance index also increases
• Increasing the compressive strength of the cement monolith by 30% or more
• Full guarantee of insulation of the reinforcement frame from vapors and moisture
• Increasing the mobility of the solution, which makes it possible not to introduce plasticizers into the composition
• Acceptability of reducing the volume fraction of cement in the mixture due to a significant increase in strength by grade

A notable drawback of these compositions is the notable increase in thermal conductivity resulting from the reduced number of air cavities, along with a corresponding decrease in adhesion with finishing materials.

In order to prevent unpleasant surprises, consideration must be given to the mixtures and solutions that finishing materials added to concrete for waterproofing will use in relation to the stone.

Waterproofing foundations is essential for longevity and durability in the construction industry. This article examines several concrete additives that are used to provide efficient waterproofing. Every kind has its own advantages and uses, ranging from more modern inventions like crystalline admixtures to more conventional choices like acrylics and silicates. These additives’ primary goal is to form a barrier that stops water from penetrating the concrete, shielding the foundation from moisture damage. Builders and homeowners can select the ideal additive depending on the requirements of a given project and the surrounding environment by being aware of how these additives work.

Properties of modern additives

With today’s concrete waterproofing additives, you can accomplish remarkable outcomes and greatly enhance the stone’s performance attributes. The level of water resistance of the finished concrete structure or product really increases to the maximum values because additives don’t fill the pores and cracks of the stone from the inside; instead, they form a high-quality waterproofing layer that prevents moisture from getting into the stone.

Contemporary mixtures are capable of more than just waterproofing. By increasing the density, those that fill the pores and seep into the stone, swelling when exposed to moisture and pushing out air, greatly boost the stone’s strength. A single addition strengthens and increases the monolith’s water resistance at the same time.

Most additives have some plasticizing properties. They remove air from the solution and increase its mobility.

Liquid additives

Concrete waterproofing additives first became available in liquid form not too long ago. They function similarly to dry compositions, but they are simpler to work with and enhance the concrete mixture’s waterproofing qualities.

The liquid comes in 500–1000 liter containers and doesn’t require preparation of the mixture or measurement of weights and proportions. It is sufficient to gather the necessary amount of liquid and add it to the concrete mixture while mixing. This kind of additive (waterproofing) for concrete removes the chance of uneven mixing, a heterogeneous mass, etc.

For individuals who handle all the work themselves, this is the easiest and least time-consuming choice. It is possible to pour concrete with this type of additive even at -30°C. Wearing personal protective equipment while working is sufficient.

Types

Concrete waterproofing additives can be purchased in powder form, which can then be diluted with liquid or water. Additives are categorized into three primary groups based on the characteristics of the effect (described below).

Polymer

These kinds of additives are added to the mixture to increase its mobility and form a polymer layer on the filler (gravel, crushed stone, and sand). The formed film ensures that even a cracked monolith will not absorb moisture when a liquid mixture is treated with additives later on.

Plasticizing

The solution is mobile thanks to additives. A collection of particles with a surface charge (for mutual sliding), the formation of an internal film, and a combined approach utilizing both of the aforementioned principles are the various principles of hydrophobization. In this situation, polycarboxylate is typically utilized, which strengthens the stone among other things.

Colmating

This type of concrete’s waterproofing additives compact the mixture that has already hardened, extending its service life and strength index by grade even in the presence of gases and aggressive inorganic and organic environments.

Colmating additives can introduce insoluble materials, such as finely ground mineral powders with pozzolanic and hydraulic activity, or water-soluble materials, such as different salts and resins, into the stone’s pores.

Domestic analogue – additive "Crystal"

One can frequently find a common additive of domestic production in Moscow and other CIS cities. When adding it to the solution during the mixing stage, it is provided as a dry mix. The powder has no smell, is non-toxic, and is safe for the environment.

Increases the solution’s water resistance to W17, enabling concrete to withstand a discernible water column. The quantity of freeze/thaw cycles reaches 60 when the strength is increased by exactly twice. Water does not cause efflorescence on the monolith when using "Crystal"; it can be used with any other plasticizer.

The characteristics of mixing must be considered when choosing concrete additives for a mixture. Thus, it is nearly impossible to combine "Crystal" with the ingredients of concrete mortar the old-fashioned way with a shovel; a concrete mixer is the only option.

They accomplish this by gradually adding the diluted additive to the already-mixed solution (1:1.5 for water to additive ratio), mixing for 15 minutes. This should be done prior to adding water to the concrete mixer. In this instance, reducing the cement content by the volume of the additive added to the mixture is acceptable. Generally speaking, one cubic meter of solution requires the addition of approximately 4 kilograms of waterproofing additive.

Foreign analogues

The most widely used addition to concrete for waterproofing foundations is Penetron Admix (USA) various elements. The material is distinct because an addition makes it more water resistant when exposed to moisture. As a result, the concrete monolith gets stronger and more water-resistant the more moisture it absorbs.

Raises the mixture’s water resistance to W20, strengthens it on average by 20%, and increases its resistance to frost to 100 cycles. About one kilogram of cement—not concrete—is used for every 100 kilograms of cement.

The liquid additive "Bisil" is quite well-liked; it reduces porosity, seals microtunnels inside the stone structure, and stops efflorescence from growing. It also makes concrete waterproof and resistant to frost. When making the mixture, the product is combined with water to create a solution.

Use of additives

Additives may be added to the solution while it is being mixed or right before it is poured into the mixture that has already been made. The volume is typically one percent of the total weight of cement added to the mixture. Examine every piece of information on the packaging. Dry mixes are typically mixed with additional modifiers.

Selecting the appropriate waterproofing additive for your concrete foundation is essential to guaranteeing its durability and ability to withstand moisture. We looked at a number of additive kinds created especially for this purpose in this article. Every variety provides distinct advantages and uses, accommodating varying environmental circumstances and project specifications.

First, when integral crystalline additives are exposed to water, they form crystals inside the concrete matrix. Over time, these crystals obstruct water pathways, strengthening the concrete’s resistance to hydrostatic pressure. This technique works well for newly constructed areas where it’s critical to have a waterproof barrier from the beginning.

Second, the additions with acrylic bases give the concrete’s surface a flexible barrier. They are simple to use and can be beneficial for both new construction and fixing problems with already-existing structures. In areas with fluctuating humidity levels, acrylic additives help the concrete resist water penetration while still allowing it to breathe.

Finally, water’s surface tension is changed by hydrophobic additives, which makes water roll off the concrete and bead up instead of seeping in. These additives work especially well on exposed concrete surfaces and in places where there is a lot of rain or standing water. They offer a barrier that lessens the absorption of water into the concrete while barely affecting its texture or look.

When selecting an additive, take your project’s particular requirements into account. Which type of additive is best will depend on a number of factors, including the intended use of the structure, soil conditions, and climate. Seeking advice from a structural engineer or concrete specialist can give you important information about which product is best for your situation.

In conclusion, choosing a waterproofing additive for concrete foundations is essential to guaranteeing long-term durability and reducing maintenance expenses. Integrated crystalline, acrylic-based, and hydrophobic additives all have unique benefits when it comes to shielding your foundation from moisture damage. You can choose an addition that will improve the longevity and performance of your concrete structures by being aware of the goals and basic workings of these substances.

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