The change in the concrete mix is one of the most significant issues between traditional forms vs. ICFs. Using the correct mix is crucial for a successful project. It saves labor, helps with consolidation, and ensures a proper pour. This post will discuss the concrete mix for ICF walls and why it’s important.
The Concrete Mix for ICF Walls: What Makes a Good Mix?
Concrete Compressive Strength
The concrete must be at least 3,000 psi to support the building’s weight. However, some projects may require a stronger mix.
Slump
A higher slump means a wetter mix, which increases pressure inside the forms. ICFs should have a 5.5″-6″ slump. Avoid adding water on site, as it weakens the concrete and can cause the aggregate to settle at the bottom.
Use a 5″ hose with a reducer to 3″ for pumping an ICF wall to maintain a steady flow and reduce the force if there’s a blockage. A flat hose like a mud snake is also common. When ordering, inform the redi-mix company that the concrete is for an ICF project.
Aggregate Size
The aggregate size is crucial for ensuring the concrete flows well and is strong enough. If the aggregate is too large, it can block the flow and create gaps in the concrete.
Admixtures
Additional ingredients in concrete, apart from cement, water, and aggregates. They enhance the concrete’s pumpability, durability, workability, and resistance to weather. Various types of admixtures are available across the country. It includes air-entraining, water-reducing, superplasticizers, retarding, and accelerating agents. In the ICF industry, common admixtures include fly ash, air, plasticizers, and superplasticizers. The concrete supplier should incorporate these admixtures during the mix design stage to achieve a good, flowable mix.
The Water-Cement Ratio Should Be Higher Than Normal
The water-cement ratio should be higher than usual for concrete used in ICF walls, ideally at .55. This might seem high. Still, the extra water makes the mix easier to work with and flow better. Plus, a .55 ratio helps reduce the chances of cracking.
Using the Wrong Concrete Mix
A bad concrete mix can harm your walls. The mix affects your walls’ strength and the pressure they put on the foundation. Working with the wrong mix can compromise the entire structure.
Using the right concrete mix ensures your building is strong and durable. Builders must be careful when selecting the concrete mix. If you have questions, you can contact your ICF supplier for guidance.
Are you interested in building with ICFs? Click here to contact the team from SuperForm. Our innovative ICF system simplifies construction while creating stronger concrete. Reach out now to learn more about the benefits of SuperForm building products.
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