Before contacting us please read through these Q&As.

About CS-21

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What kind of product is CS-21?

CS-21 is a colorless and odorless liquid. As an liquid silicate compound, it is able to activate a hydration reaction in concrete. With this, we have developed a 21st century solution to concrete-releated problems.

CS-21 is classified in the guidelines (draft pending) of the Japanese Society of Civil Engineers Concrete Library #119 / Surface Protection Method guidelines (draft pending)
Classification based on active ingredient:
■ As a "Sodium Metasilicate Impregnated Surface Material" meeting specification for "Projects with Waterproofing as a Purpose" Concrete Libary #137 - for the purpose of a "Silicate Impregnated Surface Material Construction Method" (draft pending)
■ As a "Reactive Silicate Impregnated Surface Material"

What is a concrete modifier?
A concrete modifier is a compound that works to reform and repair concrete. The application of CS-21 to concrete that has been water-cured allows for a natural reaction that raises levels of density.
What is a hydration reaction activator?
CS-21's main component, it acts upon unhydrated cement and calcium to create moisture through a hydration reaction, leading to a higher level of density. Application on concrete allows for such a reaction to continue taking place in concrete regardless of its age.
Where does CS-21 come from?
CS-21 was developed and is now made in Japan.
On what kinds of structures can CS-21 be used?
It can be used with all cement concrete structures. Primary applications include:

■ Public Structures: Tunnels, Box Culvert Structures, Water Tanks, Aquaducts and More
■ Construction: Parking Lots, Apartment Complexes, Homes and More

See examples of applications by going to our Case Studies page.

How to Use CS-21

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How do you use CS-21?
Use CS-21 in the following ways with concrete that has been water-cured:

■ Coating - Application is done with rollers, brushes and other tools. Water dampening after drying.
■ Spraying ━ Application is done with a spray-coater or spray can. Water dampening after drying.
■ Injection ━ Application is done with an injection device, injecting into cracks.

Should the CS-21 solution be used undiluted?
CS-21 should be used as is, there is no need to dillute it.
※Note: Pages 56 and 58 of the guidelines titled "Silicate Impregnated Surface Material Construction Method" (draft pending) state: "Solidified and reactive silicate materials for impregnating surfaces should not be diluted."
How does CS-21 react when applied on concrete?

1. Properties and States
CS-21 is a liquid solution. When dried in becomes a thick syrup. When dried furhter, it becomes a glassy-solid. When the solid form is immersed in water, it absorbs the water and returns to a thick syrup state, eventually returning to a liquid solution. This process can be sped up with stirring.

2. Reaction on Concrete
When CS - 21 is applied to, sprayed on, or injected into hardened concrete, it reacts with the calcium content in concrete to create crystals that are water-insolvent. These crystals are similar to those created by the process of water-curing cement.

3. Hydration Reaction on Concrete
CS-21 creates a reaction making crystals water-insolvent. These crystals fill cracks and lead to higher density levels in concrete.

※1: CS-21 dissolves in water even after drying.
※2, 3: The reaction with water makes water-insolvent crystals.
Is CS-21 safe to use?
Yes. CS-21 is an eco-friendly inorganic material that is safe to use. It contains no harmful substances. It is safe for use on concrete structures coming into contact with drinking water. For example, it is used to coat the entire surfaces of water reservoirs.
Note: As an alkaline substance, it should not come into direct contact with skin or eyes.

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