Concrete admixtures greatly improve the performance, durability, and appearance of concrete, whether used in driveways, skyscrapers or wharves. These admixtures allow you to customise the concrete’s properties to meet specific project needs, for example, accelerating setting times in cold climates or boosting resistance to environmental and chemical stresses.

Without the availability of admixtures for cement, mixing, transporting, placing, and finishing concrete becomes much more challenging. The concrete mix may be either too stiff or too fluid, leading to complications in its application and compromising the overall quality of the construction. It may not flow smoothly into forms, making it difficult to achieve a level, uniform surface; it may be too permeable to water or too prone to cracking.

Depending on which admixtures you select, you can significantly improve the concrete’s workability, making it easier to handle and more adaptable to various construction scenarios. These scenarios include high-rise buildings and large infrastructure projects, where admixtures for high strength concrete are essential for achieving the required load-bearing capabilities; coastal regions, where corrosion inhibiting admixtures protect against salt air; and underground projects, where waterproofing admixtures ensure durability despite prolific groundwater.

What is a Concrete Admixture?

A concrete admixture is a special ingredient added during the mixing process to improve the characteristics of the mix. Admixtures for cement can alter setting times, improve workability, increase strength, and provide additional benefits like waterproofing and corrosion resistance.

Types of Admixtures Used in Concrete

Admixtures used in concrete must be carefully selected to enhance the final product. You not only need to know the benefits of each admixture, but you also need a comprehensive understanding of your project’s specifics, including the soil type, potential groundwater intrusion, and any harmful chemicals in the soil. This detailed insight ensures that your concrete is specifically formulated to address your project’s specific demands and challenges.

Below, you’ll find three popular admixtures: corrosion inhibiting admixtures, waterproofing admixtures, and admixtures for high strength concrete.

  1. Corrosion Inhibiting Admixtures

These admixtures are crucial for structures exposed to corrosive environments, such as near the ocean or where de-icing salts are used. Corrosion-inhibiting admixtures help protect the steel reinforcement in concrete from rusting, extending the structure’s longevity and durability. They are used in industrial facilities, wastewater treatment plants, roads, bridges, and coastal structures.

  1. Types of Waterproofing Admixtures for Concrete

Waterproofing admixtures prevent water penetration in structures like basements, swimming pools, and other submerged or underground facilities. These concrete admixtures reduce porosity and enhance the water resistance of concrete, ensuring durability in wet conditions. There are different types of waterproofing admixtures for concrete, as follows.

  • Hydrophobic Admixtures: Best for surfaces exposed to moisture but not submerged; ideal for exterior walls, roofs, and decks.
  • Crystalline Admixtures: Suitable for structures with high risk of microcracking; perfect for foundations, basements, and water tanks.
  • Pore Blocking Admixtures: Great for dense concrete applications; recommended for slabs, floors, and anywhere with direct water contact.
  • Permeability Reducing Admixtures: Essential for subterranean structures under high water pressure, such as tunnels and underground facilities.

  1. Admixtures for High Strength Concrete

These admixtures increase the compressive strength of concrete, making it ideal for structures requiring high load-bearing capabilities. This makes admixtures for high strength concrete critical when constructing skyscrapers, bridges, and other major infrastructure projects where durability and strength are essential. They ensure the concrete can withstand considerable stresses over long periods, maintaining structural integrity.

What About Liquid Admixtures for Concrete?

Liquid admixtures for concrete are popular because they are easy to mix and have consistent distribution within the concrete. For these reasons, they are often used in preference to powered admixtures. All three of the above admixtures are available in liquid or powder form.

How to Determine the Best Admixtures for Your Project

Choosing the right concrete admixture involves considering several factors:

  • Project Requirements: Understand the specific needs of your project. Whether it’s high strength, rapid setting, or resistance to environmental conditions, the primary requirements will guide your choice.
  • Environmental Conditions: The local environment plays a crucial role in selecting the correct admixtures for cement. For projects in cold climates, an accelerating admixture might be needed to reduce setting time during colder months. Similarly, a corrosion-inhibiting admixture for cement is ideal for coastal projects.
  • Compatibility with Other Ingredients: Ensure that the admixture works well with other components of the concrete mix, such as the type of cement and aggregates.
  • Quality and Compliance: Choose admixtures that comply with relevant standards and regulations to ensure quality and safety in construction.
  • Cost-Effectiveness: Evaluate the cost implications of different admixtures and balance them against the benefits they bring to the project.

Essential Considerations Before Making a Decision

Selecting the right concrete admixture is more than just picking a product off the shelf – it’s about understanding the complex interplay between concrete components under specific conditions. Contact the SPG Go Green team today to help select the correct admixture for your project.