THE APPLICATION PROCESS

  • Step 1: Spray apply Waterproofing Agent over the entire surface (and allow it to dry to the touch). Then water the entire area with water (and let it dry to the touch).

  •   Step 2: Spray apply ACR Crack & Void Treatment on any visible cracks, and then spray apply ACR Accelerating Agent over the entire surface (and allow it to dry to the touch) then water the surface again.

  • Step 3: Complete any required Flashing work at all angle changes, drains, penetrations through the deck, etc.

Once the Waterproofing Agent has been applied and watered in (Step 1), a chemical reaction will begin to occur, that creates a protective waterproofing gel.

The chemical reaction that forms this gel occurs ½” – ¾” below the surface of the concrete, and prevents any water, chemicals, chloride ions, etc. from reaching the steel reinforcement bars that were placed in the concrete during the construction of the structure.

This gel does not form on the surface of the concrete and does not change the appearance of the concrete surface. It also does not affect the slipperiness coefficient of the surface, or the ability of other products to adhere to it.

NOTE:      Paint, coatings, paving asphalt, etc. can be applied to the surface of the concrete following the completion of the waterproofing system (if desired).

THE CHEMICAL REACTION

The following components are necessary for this biochemically modified silicate gel to form below the surface of the concrete:

  • TechCrete 2500 Waterproofing Agent

  • Calcium (readily available in the concentrate)

  • Water

  • Carbon Dioxide

TechCrete 2500 penetrates below the surface of the concrete during the initial application and remains reactive inside the matrix of the concrete indefinitely. As future cracks occur, rainwater will reactivate the chemicals, forming new gel and sealing the cracks as they occur. Stable cracks up to 2.0 mm in width will be sealed during the application of the waterproofing, and future cracks up of to 0.4 mm in width will be sealed for the remaining service life of the structure. Any stable cracks that are wider than these dimensions, and any structural or moving cracks must be properly addressed using Alchemco ACR repair products, as outlined in Alchemco's Crack Treatment procedures.

TechCrete 2500 Waterproofing Agent has a unique and proprietary, biochemically modified catalyst that separates it from all other spray applied concrete sealers and waterproofing products.

A catalyst is a material that speeds up or slows down a chemical reaction, without changing the chemical reaction itself. When TechCrete 2500 Waterproofing Agent is used to waterproof a concrete structure, there are two distinct catalytic reactions that occur, creating a Virtuous Cycle or 'Repeating cycle' that continually repeats itself over & over for the remaining service life of that structure.

TechCrete 2500 Waterproofing Agent is primarily made up of silicates, combined with this proprietary biochemical catalyst. During the application, the silicates within TechCrete 2500 Waterproofing Agent react with metallic ions in the concrete (primarily the calcium hydroxide that is a by-product of cement hydration). During this stage, TechCrete 2500 Waterproofing Agent is highly reactive, and creates a complex Calcium Silicate Hydrate (CSH) gel. This gel swells when it comes in contact with water (blocking cracks, pores, capillaries, voids, etc.) waterproofing the concrete, and preventing the penetration of water.

Over time, Carbon Dioxide from the atmosphere extracts some of the Calcium from the CSH gel to form Calcium Carbonate. This creates an inert mass that further reduces the permeability and porosity of the concrete, by permanently blocking the cracks, voids, micro- fractures, etc.

NOTE: the 'carbonation of concrete' problem that is usually associated with Carbon Dioxide, is not a problem for TechCrete 2500 … because this repeating cycle allows it to actually increase the pH of the concrete surrounding the steel reinforcement, instead of lowering it.

HOW TECHCRETE'S WATERPROOFING SYSTEM WORKS

The TechCrete® Waterproofing System is a biochemically modified silicate material that can remain reactive inside the cracks and matrix of concrete for the life of the structure!

Dynamics:

The foundation is catalytic reactions of which there are two:

  1. The calcium carbonate acts as a consolidating “glue” and “space filler” in cracks, pores and capillaries.

  2. Calcium Silicate Hydrate Gel plays a vital role — being flexible allows for small dynamic movement such as shrinkage and thermal movement

When in contact with water, the gel swells, filling remaing spaces and blocking them from allowing water to pass. The TechCrete 2500 Waterproofing Agent, along with its supporting product-line, is able to produce more mass than when originally applied — i.e. it “grows” to seal new cracks that develop after application!

Stage 1:

When TechCrete 2500 Waterproofing Agent is applied to concrete, and watered in, it penetrates the concrete and the silcates react with available metallic ions (mainly calcium in hydroxide form). A reaction between Calcium Hydroxide and other ions forms a high-ratio Calcium Silicate Hydrate Gel.

Stage 2:

As the concrete dries, a reaction between the Calcium Silicate Hydrate Gel & Carbon Dioxide forms low-ratio gel and Calcium Carbonate as a by-product.

Stage 3:

If a crack forms, water will create a reaction between Calcium Hydroxide and the low-ratio Calcium Silicate Hydrate Gel to form a high-ratio Calcium Silicate Hydrate Gel which, with assistance of the Calcium Carbonate by-product, seals the crack helping to prevent further water seepage.

The cycle continues so long as water, calcium or other ions and carbon dioxide are available!

THE VIRTUOUS OR REPEATING CYCLE:

In order for TechCrete 2500 Waterproofing Agent to seal all future cracks that form after the application, it must produce more mass than was originally applied… in other words, it must 'grow'.

When Carbon Dioxide in the atmosphere extracts some of the Calcium from the waterproofing gel, it leaves a 'low ratio' version of the CSH gel. As a result of this interaction, the 'low ratio' waterproofing gel is once again 'ready to react', and actively looks to attract Calcium ions to bring it back into equilibrium. So, when water enters the concrete, the cement continues to hydrate, and through the process of diffusion within the concrete, the Calcium moves from areas of high concentration to areas of low concentration. The 'low ratio' CSH gel then reacts with the newly available Calcium and once again becomes a 'high ratio' CSH gel. At this point, the cycle begins all over again with the 'high ratio' CSH gel reacting with Carbon Dioxide in the atmosphere to once again form Calcium Carbonate … which permanently plugs the cracks, pores, microfractures, voids, etc. (once again leaving a 'low ratio' CSH gel in place).

This ongoing chemical reaction creates a dynamic and reliable self-healing process within the concrete. The process of 'carbonation' is generally considered detrimental to concrete, because it lowers the pH level of the concrete (which deteriorates the protective 'passive layer' surrounding the steel reinforcement bars and allows corrosion to occur). TechCrete 2500 Waterproofing Agent does not have this problem. It creates a 'repeating' carbonation cycle which does not lower the alkalinity level of the concrete, but in fact increases the alkalinity level. This action actually enhances the protection of the steel reinforcement. In addition, the Calcium Carbonate that is formed during this carbonation cycle increases the long-term durability of the concrete.

The difference between TechCrete 2500 and normal silicate products is that the biochemical catalyst allows this carbonation cycle to repeat itself indefinitely … instead of only occurring once. Normal (non-modified) silicates get stuck when they go thru the carbonation process and are not available later to react again. As a result, these other silicate-based products are not even able to seal 'existing cracks', much less any 'future cracks' that will occur in the concrete.

Also, the fact that there are two reaction components that occur when using TechCrete 2500 Waterproofing Agent is important. The Calcium Carbonate that is formed acts as a consolidating glue or space filler, in the cracks, pores, capillaries, etc. The CSH gel also plays a vital role, because not only does it allow the virtuous cycle to occur over and over (a Calcium Carbonate factory), but this colloidal gel is not rigid like crystalline technology products are; so it allows for small dynamic movements such as shrinkage or thermal movements in the concrete.

In summary, when TechCrete 2500 Waterproofing Agent comes in contact with water it forms a waterproofing gel that swells; filling and blocking off the spaces (cracks) that allowed the water to enter. Then the 'factory' gets to work depositing Calcium Carbonate to permanently seal it. The waterproofing gel will then remain 'dormant' until water comes in contact with it again.

NOTE: using Scanning Electronic Microscope (SEM) Photography, it is possible to confirm that TechCrete 2500 Waterproofing Agent was applied as per specifications. If the product has been substituted, diluted, or applied without the critical watering steps, the SEM photos will reveal that.