Best Practices for Concrete in Coastal Environment

12th December 2024

As with many areas, concrete is popular in coastal projects because it is a strong and durable material. However, a coastal setting brings with it a very specific environment and atmosphere which impacts concrete more than other settings might; saltwater, high humidity, and sea spray can accelerate wear and corrosion. Therefore, there are a few things you can do to improve its durability and performance in these environments.

From choosing the right mixes, to following best practices when pouring or pumping it and applying protective sealants, you can make sure your concrete is in the best position to withstand the harsher environment of the coast.

At 2 Brothers Concrete & Pumping, we provide concrete across the South Coast, making us experts at dealing with concrete in coastal conditions. With a combined 25 years of experience in the industry and area, we have a wealth of knowledge on how to produce and pump concrete in salty sea air conditions.

In this blog, we share all the tips and tricks for concrete in a coastal environment.

Unique Challenges of Concrete in Coastal Areas

Coastal environments pose unique challenges to concrete in several ways.

Sea-salt-induced corrosion - seawater contains chlorides, which can corrode reinforcing steel and degrade concrete over time.
Moisture penetration - the air can be quite moist because of the seawater, so if the concrete cracks, it is at risk of moisture penetrating and causing further issues.
High winds - wind speeds can impact the curing of concrete, affecting the overall strength and durability of the material.
Freeze-thaw cycles - the cycle of freezing and melting can have an impact on the strength and durability of the material.

So, how do you combat these?

Choosing the Right Concrete Mix for Coastal Environments

One of the first things you need to do is pick the right concrete design mix. This means choosing the right ratio of ingredients and adding any additives to make the concrete meet its purpose.

Choices can include:

Low permeability - choosing a concrete that doesn't allow water or salt to infiltrate the surface. You can also add pozzolanic materials like fly ash or slag to enhance durability.
High-quality aggregates - aggregates are a core ingredient in the material and using quality primary stones will prevent salt water from causing issues.
Anti-corrosion mixtures - if using steel reinforcement, you can choose to add chemical admixtures that protect the metal from corrosion and chlorides.

Best Practices for Concrete Placement and Curing in Coastal Areas

As well as choosing the right concrete mixture for your project, it is also important that it is poured or pumped in the right conditions and the correct way.

The moisture in the air and high winds can impact curing times, which affects the strength and durability of the dried concrete. This needs to be considered when preparing for the concrete delivery.

Thorough Curing

Ensuring that the concrete cures thoroughly and all the way through is essential:

Enhance strength - proper curing allows the concrete to achieve its designed strength, making it resilient against mechanical and environmental stresses.
Reduce cracks - coastal areas often experience temperature fluctuations and high winds, which can cause premature drying and cracking. Thorough curing minimises this risk.
Prevent surface weaknesses - well-cured concrete develops a denser, more uniform surface, reducing its vulnerability to saltwater infiltration and corrosion of reinforcement.

Maintaining Moisture

Controlling moisture during the curing process is vital in any environment as it prevents cracking.

The high-speed winds experienced in coastal areas often accelerate the moisture loss, which weakens the concrete. To prevent this, you can:

Use curing compounds - apply a liquid curing compound to seal the surface and retain moisture. This is especially effective in windy or hot conditions.
Cover with moisture-retaining materials - use wet burlap, plastic sheeting, or other moisture barriers to shield the concrete surface. Ensure the coverings are securely anchored to prevent displacement by wind.
Frequent watering - keep the surface damp using a fine mist of water, especially during the early stages of curing. Avoid flooding, as it can cause surface erosion.
Build temporary wind barriers - put up barriers around the site to reduce wind exposure and prevent rapid drying.

Applying Protective Coatings and Sealants

In a coastal area, adding a finish and sealing the concrete is a crucial step and one that isn't typically needed in other situations.

Adding a protective layer enhances the concrete's ability to resist coastal challenges like those mentioned above.

Surface sealing - apply a high-quality sealant to create a protective barrier against moisture and salt penetration.
Smooth and compact finish - achieving a compact, smooth surface minimises microcracks where water can seep in, reducing the risk of internal damage and salt intrusion.
Waterproofing sealants - use high-quality waterproofing sealants specifically designed for coastal applications to provide an additional layer of defence against salt and moisture, reducing the risk of surface degradation.
Anti-corrosion coatings - applying epoxy coatings or other protective layers on exposed steel and concrete surfaces is vital in coastal areas to shield steel reinforcements from rust and prevent moisture intrusion into the concrete matrix, preventing long-term damage and preserving structural integrity.
Surface finishes - consider finishing treatments like densifiers or hydrophobic coatings. Densifiers strengthen the surface by filling pores and reducing permeability, while hydrophobic coatings repel water, ensuring that the concrete remains less susceptible to moisture-related damage.

Reinforcement Protection Strategies

If using steel or metal to reinforce the concrete structure, it is pivotal that these are protected because the salt water can corrode the metal, weakening it.

There are a few ways you can do this:

Galvanised or epoxy-coated rebar - this provides a protective barrier stopping direct contact between the metal and salt, reducing the risk of corrosion.
Stainless steel rebar - opt for stainless steel, which is less likely to rust, ensuring long-term durability.
Concrete cover depth - increasing the concrete cover depth over rebar provides an extra layer of protection against moisture and salt ingress, reducing the risk of corrosion.

Regular Maintenance and Inspection

Regular maintenance and inspections are important to concrete maintenance anywhere, but this is even more important in coastal areas.

Conducting frequent inspections will allow you to spot any cracks or issues quickly, giving you time to repair them before salt and moisture get into the structure and cause problems.

You will also need to reapply any sealants to make sure they are still covering the surface and providing the protective barrier they are intended to.

Get Coastal Concrete Expertise From Us

Producing concrete and pumping it in a coastal area has several layers of complexity that need to be considered, from the type of concrete mix being produced to creating the right environment for proper curing and adding additional finishes as a protective barrier.

At 2 Brothers Concrete and Pumping, we are experts at it all. Predominantly working across the South Coast, we have worked on many projects where moisture and high winds need to be considered during the process.

If you have a project that needs concrete in a coastal area, don't hesitate to get in touch with our specialists for advice and guidance. We can help you work out what concrete you need and produce it on your site so you only pay for what you lay. Plus, our pump hire makes getting the concrete from our volumetric truck to your site easy and hassle-free.

Call us today on 01489 552737 or complete our online contact form, and we will give you a callback.