Denka Power CSA-S (Replacement product for Denka CSA#20)

The world’s best shrinkage compensating cement additive.

Since 1968, Demden has been supplying Denka CSA#20 to a variety of NZ concrete product manufacturers and construction projects.  That’s over 40 years of proven results.

Denka CSA#20 (Calcium Sulpho Aluminate) is an Expansive Cement Additive used to chemically pre-stress concrete, providing compensation for drying shrinkage, and reducing or even completely eliminating shrinkage cracks.

It is typically used in New Zealand to create large concrete slabs with fewer construction joints and without saw cuts.  In fact, Denka CSA#20 has been successfully used to construct joint-free single slabs of up to 3080m2 (65m x 60m) in New Zealand.

Denka CSA#20 has been replaced in during 2024 with a new version, Denka Power CSA-S. Denka Power CSA-S is a lower dosage equivalent leveraging a higher free lime content to allow it to produce shrinkage compensating ettringite at a lower dose, when compared to Denka CSA#20.

Key Benefits

• Allows for larger placements without control joints
• Significantly reduces or eliminates shrinkage cracks
• Greatly reduces number of control/construction joints
• Greater freedom in the layout of concrete placements
• Allows faster and simpler construction
• Reduces surface maintenance

Recommended for:

Denka CSA is particularly useful in large warehouses with high level racking. The result is greater durability and less damage from forklift traffic.

How does Denka CSA work?

Denka CSA is always mixed with Type GP Portland cement, in correct proportions. It can also be used in mixes containing SCM's.

As the resulting concrete is curing and gaining strength, it expands. Bonded to the steel, this expanding concrete causes the steel to be stretched slightly, placing it in tension.  As drying shrinkage takes place, the steel is relieved.

When the ratio of Denka CSA to cement is increased, its high expansion qualities make it ideal for use in pre-stressed concrete. 

Specifications and reinforcing guidelines are available on request.

Demden are New Zealand’s exclusive suppliers of Denka CSA.