Watertight concrete with waterproofing admixtures

What are crystalline waterproofing admixtures?

Concrete is one of the most widely used building materials in the world, but it has a major drawback: it is porous and permeable to water and other liquids. This can lead to deterioration, corrosion, cracking, staining and leakage of concrete structures, especially in harsh environments or when exposed to high hydrostatic pressure. To prevent these problems, concrete must be protected from water ingress. One of the most cost effective and durable ways of waterproofing concrete is through the use of crystalline waterproofing admixtures.

These crystalline waterproofing admixtures are special active chemicals added to the concrete mix during the mixing process that react with water and certain cement hydration products to form insoluble crystals that fill the pores, capillaries and micro-cracks in the concrete matrix. These crystals block the passage of water and other harmful substances and also help to accelerate the self-sealing of any new micro-cracks that may form due to shrinkage or stress. In the following illustration you see how crystals grow in the pores of the cement stone and reducing the water permeability. 

The effects of waterproofing admixtures

Crystalline waterproofing admixtures have two types of waterproofing effect: immediate and delayed. A portion of the admixture reacts with water and cement hydration products during the setting and hardening stages and forms crystals as the concrete sets, sealing early porosity and micro-cracks. The remaining unreacted portion of the admixture remains dormant until it comes into contact with ambient water (e.g. leaks through a newly formed micro-crack) and begins to form crystals to accelerate self-sealing. In this way, waterproofing admixtures provide both immediate and continuous waterproofing protection. It is therefore important to note that in dry or low humidity conditions they may take longer to activate and provide waterproofing protection, or may not be effective at all.

An important criterion for crystalline waterproofing admixtures is that they do not adversely affect the other properties and performance of the fresh and hardened concrete, such as workability, setting and hardening rates and mechanical properties.

Applications and benefits of waterproofing admixtures

Crystalline waterproofing admixtures are suitable for various applications such as:

• Foundations, basements and underground structures subject to high water pressure or groundwater infiltration.
• Water tanks, reservoirs, dams and pipelines that need to store or transport water or other fluids without leakage or contamination.
• Bridges, tunnels and marine structures exposed to harsh weather conditions or saltwater corrosion.
• Roofs, balconies and terraces that need to prevent rainwater infiltration and seepage.

Crystalline waterproofing admixtures offer many benefits to concrete structures. These include:

• Providing permanent and integral waterproofing protection, independent of external coatings or membranes that may degrade or delaminate over time.
• Improving concrete durability by reducing porosity and permeability, and increasing resistance to chemical attack, freeze-thaw cycles and other water-related damage.
• By extending the service life of concrete structures, they reduce the cost of maintenance and repairs.
• They are environmentally friendly and safe to use as they contain no volatile organic compounds (VOCs) or harmful substances that can leach into the soil or water.

Crystalline waterproofing admixtures save time and money and provide long-lasting protection

Crystalline waterproofing admixtures are a recognised technology for improving the quality and performance of concrete structures that provide long-lasting waterproofing protection that can withstand various environmental and operational challenges. They can also save time and money by simplifying the construction process and reducing the need for additional waterproofing systems or treatments. Crystalline waterproofing admixtures are a smart and sustainable choice for any concrete project that requires a good, easy-to-use, value-adding waterproofing system.

With the Centrament Proof crystalline waterproofing system from MC-Bauchemie, you will find the right type of product for your unique circumstances.