Concrete Admixtures

Concrete, the single most widely used building material in the world, has a history dating back to the Romans and ancient Egyptians. Given that concrete is used twice as much in construction over all other building materials, emphasis on quality, performance and sustainability is essential for the industry to grow and thrive. One of the most important ingredients in high performance, long-lasting, durable and beautiful concrete produced today are concrete admixtures. Concrete admixtures are natural or manufactured chemicals or additives added during concrete mixing to enhance specific properties of the fresh or hardened concrete, such as workability, durability, or early and final strength.

Concrete can meet many adversities on site during and after project completion including chemical and mechanical corrosion water ingress and weathering, most chemical weathering in concrete is caused by attack by contaminants in water, soil or gases (e.g., air). Hazards also occur in service (i.e., in tanks, industrial floors, wastewater treatment facilities etc.). • Surface and ground water, harmful soil contaminants, air pollutants, vegetable and animal substances can attack the concrete chemically.

Chemical attack can be divided into two types:

• Dissolvent attack: caused by the action of soft water, acids, salts, bases, oils and greases etc.
• Swelling/spalling attack: caused mainly by the action of water-soluble sulphates (sulphate swelling)

Concrete only has adequate resistance against very weak acids. Medium strength acids degrade the concrete. Therefore, extra protection of the concrete with a coating must always be specified for moderate to highly aggressive acid attack.

With the many formulations at Sika for concrete admixtures we are also very well equipped to advice on the right combination to achieve sulphate resistance for your concrete to guarantee long lasting projects for Bridges fully submerged structures and areas with high sulphate content. The right combination of Sika® Viscocrete® / SikaPlast® / Sikament® and an addition of SikaFume® can decrease the rate of sulphate attack on your structure and assure you to achieve the promised lifespan for your project.

These four Sika products provide the following protection:

• Concrete structure as impermeable as possible i.e low porosity due to use of SikaFume® technology.
• Helps you achieve low water/cement ratio aim for ≤ 0.45 use Sika® Viscocrete® / SikaPlast® / Sikament®
• Curing suited to the structure.

Note: Clarification of specific requirements is essential for every project to assist us in providing you with the right solutions             for your site.