ᐅ Concrete slab with polymer fibers and reduced reinforcement steel

Hello everyone,

Let me briefly introduce myself, as I’m new here.

My wife and I decided at the beginning of 2023 to build a house, and we are working with the companies Danwood and Glatthaar to construct a small one-and-a-half-story detached house.

We recently had the site kickoff meeting with Glatthaar, which went well – we’re excited that the project is finally starting.

Afterwards, I was told on the phone that our house is suitable for a "hybrid slab," and Glatthaar would like to use this to improve their environmental balance.

Today, I received a letter about this. Unfortunately, it doesn’t contain any concrete information, such as how much steel will be reduced or the amount of plastic fibers added to the slab. I have no clue.

So my question is: is this a good solution? Of course, I’m skeptical – like many others building a house, we expect to live in it for a long time. I don’t want the foundation slab to cause problems later on.

Here is a quote from Glatthaar’s letter:

They plan to use "a combination of reinforcing steel and MasterFiber polymer fibers." Furthermore, "the addition of polymer fibers is approved by the DIBt (German Institute for Structural Engineering)."

What do you think? Is this a viable method, or is it better to avoid it?

Best regards and thanks in advance for all your answers!

What interests you about their ecological balance....

Build with steel, then you know what you have. If you want to be sustainable, your everyday life offers you far better alternatives....

Technically, I can't say anything about the polymer board – I just find it odd to shift the ecological balance onto the customer....

I would politely give them a firm no thank you.

What does the supervising structural engineer say about this?

Introduction 2016:

The German Institute for Construction Technology (DIBt) has approved three polypropylene (PP) microfibers and three polypropylene macrofibers from the MasterFiber product range by Master Builders Solutions®. These six polymer fibers can therefore be used as concrete additives according to DIN EN 206 Part 1 in conjunction with DIN 1045 Part 2.

The newly approved PP microfibers MasterFiber 006, MasterFiber 012, and MasterFiber 018 are mainly used in industrial floors, screeds, and thin-walled concrete components. They improve the cohesion of fresh concrete. In the event of cracks, the fibers bridge the cracks and reduce continuous cracking. This significantly minimizes crack formation caused by plastic shrinkage. Even with a fiber content of 0.1% of the concrete volume, the total crack area is reduced by 30 to 40%.

In comparison to the microfibers, the macrofibers MasterFiber 244, MasterFiber 249, and MasterFiber 254 are approved for load-bearing applications in concrete. The extruded polypropylene MasterFiber macrofibers have a low impact on the rheological behavior and workability of fresh concrete. Due to their load-bearing capacity, the macrofibers can partially or completely replace steel reinforcement. The plastic fibers are corrosion-resistant, enabling durable and slender components. Main areas of application include industrial floors, outdoor surfaces, agricultural areas, and precast concrete elements.

So basically suitable. In coordination with the structural engineer, I would have no concerns.

Wow, that was quick.

Thanks in advance for the answers.

I completely understand the point made by @Gerddieter.

As @Rübe1 and @jens.knoedel suggested, I will send the email to the structural engineer right away. Let’s see what they say.

@jens.knoedel, is there a reason why this is mainly used for industrial floors? Are industrial floors subject to stricter regulations than those in residential settings?

I’m also curious about this:
According to Glatthaar on the phone, a concrete slab with polymer fibers is significantly higher quality and actually even more expensive.
Is that true regarding the price?

roestzwiee schrieb:

I was later told over the phone that our house is suitable for a "hybrid slab," and Glatthaar would be happy to install this to improve their environmental footprint.

Interesting. That the concept of "fleet consumption" has now reached concrete slab manufacturers was new to me as well. But it has always taken decades for ideas to transfer into other fields.

Gerddieter schrieb:

Build with steel and you know what you have. If you want to be sustainable, your daily life offers plenty of better alternatives...

Building a house is not an advertisement for detergent, and the environmental impact can certainly be improved in several areas. How sustainable this is, I don’t know: I am not aware of any recycling methods for these new concrete mixes. However, on balance, that wouldn’t stop me from adopting this advancement here.

jens.knoedel schrieb:

Basically suitable. I would have no concerns when coordinated with the structural engineer.

I agree.

roestzwiee schrieb:

Is there a reason why this is mainly used for industrial floors? Are industrial floors subject to stricter standards than those in private homes?

At home, maybe grandma rides a motorcycle in the chicken coop once in a while; in an industrial hall, forklifts race across the floor every day. The pressure and abrasion are incomparably higher.

roestzwiee schrieb:

According to Glatthaar over the phone, a slab with polymer fibers is significantly higher quality and actually even more expensive.

I imagine producers might even be subsidized to promote the innovation without additional cost.

Steel contains immense amounts of process energy; the bars don’t grow on trees. They are just as much "synthetic fibers," only made of metal.

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