#2 - In conversation with TBI and Penetron Benelux on sustainability, life extension and CO₂ savings of concrete

Transcript

Episode 2
Conversation with Niki Loonen (TBI), Olivier Suerickx (Penetron Benelux) and Bob Lambermont (Penetron Benelux)
Host: Roel van Gils

[00:01] Introduction and presentation of guests
Roel van Gils: Welcome to this episode of Concrete and Steel Construction, the podcast. Live from the Louwers Mediagroep studio in Weert. We will be discussing sustainability, extending service life, and CO₂ savings in concrete. These are topics that are undergoing profound changes in the construction sector today. Joining me at the table is Olivier Suerickx from Penetron Benelux.
Olivier Suerickx: Good afternoon.
Roel van Gils: Good afternoon. Bob Lambermont, also from Penetron. And Niki Loonen from TBI. Gentlemen, welcome, everyone. Thank you. Please introduce yourselves.
Niki Loonen: My name is Niki and I am a concrete sustainability specialist at TBI. I help construction companies to use increasingly sustainable concrete in their projects.
Olivier Suerickx: I am Olivier Suerickx from Penetron Benelux, managing partner. My role within the organization is primarily commercial and technical. We focus on sustainable solutions that extend the life of concrete structures. Technologies such as healing, self-healing concrete are making many things possible in construction today.
Roel van Gils: Thank you.
Bob Lambermont: My name is Bob Lambermont. I work for P&O International as a specification manager. In that role, I travel all over the world. I visit many places to monitor projects from the outset in terms of specifications. As a result, I am often involved with what is happening in the world, in different countries, with new types of cement and new concrete mixes. What is actually being used in practice?
Roel van Gils: Once again, welcome, everyone. We are already talking about CO₂ neutrality, the circular economy, and energy-efficient construction, but the reality in this area often proves to be stubborn. How big is the problem in the construction industry?
Niki Loonen: Well, if I may begin. Yes, quite large. We do, of course, have a pretty good idea of what the limits of Paris are. The Dutch Green Building Council has done some interesting research into what the impact of construction should be. And I think we are currently at least a factor of two or more above that with average construction projects. And that limit is going to be halved again in the coming years, because we have to emit less and less. So we really need to achieve reductions of 50 percent already in order to on par to achieve that one and a half to two degrees. And that needs to be halved again by 2030 or 2035.
Roel van Gils: Okay, we have formulated a number of propositions. Perhaps we can start with proposition one.
Niki Loonen: Yes.
Roel van Gils: Unless you have anything to add, Olivier.
Olivier Suerickx: Yes, not specifically. I agree with Niki. I think the biggest problem we have is that cement production and concrete are responsible for approximately 81% of global CO₂ emissions. Something really needs to be done. I think that's important and that it really needs to be put into practice. I think that everyone in the concrete industry, or construction in general, needs to get involved in order to achieve something.
Roel van Gils: Yes, that might be a nice bridge.
Bob Lambermont: I still see differences between countries and types of customers. So you have countries and types of customers who are completely unconcerned about CO₂, who only care about price and want their homes built as quickly as possible. Awareness is growing, though. I've just returned from a trip to Latin America, where you can see that awareness is growing, and in some countries it's much further along than in others. We actually have opportunities there. Some customers demand more sustainability, and that is becoming more important. Other customers are not concerned about that at all, but they are sensitive not to CO₂ emissions, but to sustainability.
Niki Loonen: Yes, look, we see that in the Netherlands, for example, financiers and housing associations are already imposing stricter requirements on primary raw material use in terms of CO₂, and that developers and contractors are really being asked to build on that. So I see the movement in the right direction, but we have a long way to go.

[04:41] Proposition: sustainability in construction is still too often a marketing term.
Roel van Gils: So our first proposition, that sustainability in construction is still too often just a marketing term, is that still true?
Niki Loonen: That may be partly true, but I am seeing more and more sincerity in the desire to move in that direction. I also see that in many places it is difficult to really put this into practice. And that you then try to make the small things a little bigger out of desire, so that you can be proud of something. And that is good, of course, because it inspires others. But the steps we need to take are still quite big.
Roel van Gils: And what is the reason for that?
Niki Loonen: I always say that the power of habit is very strong. So what you are used to doing is very difficult to change. Even though you know, just look at yourself. In my case, I like sugar, so I'm a real sugar junkie. And I know it's not good for me. But yes, that's really difficult. The power of habit is so strong. And I think everyone has something for themselves that they think, yes, I really shouldn't do that, but I do it every day anyway. And that's no different with building. What you're used to doing is very difficult to break away from and do something else. But it is necessary.
Roel van Gils: And is that also due to a lack of knowledge, for example?
Niki Loonen: Yes, I think that's partly natural, partly due to knowledge, but of course there's also very little knowledge about the way we build today. So I think there are very few people who work with concrete who understand how concrete is put together. For someone who works with concrete, it has to be workable. And it has to achieve a certain strength and environmental class. And if the concrete plant says it does, then it's not really someone from the past who said, yes, but what exactly is in it? And I have to be honest and say that at a certain point, I also give up on cement chemistry. That I don't know either. So I think that, and of course we have to do a lot in terms of education and training. But I think it really starts with a genuine desire to take those steps.
Olivier Suerickx: I think that's a nice comparison you make with sugar. I would actually like to turn it around to coming out of our comfort zone. Coming out of our comfort zone, being open to new things or working differently. That's really a movement we need to set in motion. Sometimes you have the customer on board, but of course it's not just the customer. There are various parties involved in a construction process. Everyone has to be on the same page. And I think that's where the difficulty lies.
Bob Lambermont: Indeed, it's often about responsibility. And then everyone thinks: okay, we'd really like to use new technologies, but maybe someone else could try it first to see if it works. And yes, everyone keeps looking at each other. What is very positive, I think, is the awareness and the fact that everyone is putting it on their front page, that CO₂ is a target, a goal we need to take steps towards, that we can reduce. And that has set a lot of things in motion in the concrete world to look for solutions where, in the past, yes, that was all immediately dismissed. Now that possibility exists, there is much more openness.

[08:28] Proposition: forget circular construction, extending service life comes first
Roel van Gils: Yes, okay. But anyway, that ties in nicely with the next statement. We talk a lot about circular construction, but we forget that extending the lifespan is actually the first step. How can existing structures last longer, for example? Do we have an example of that?
Niki Loonen: I always use the Pantheon as an example. Oh, really? A 2,000-year-old concrete structure built by the Romans. On the one hand, it's a myth to say that Roman concrete was so much better than ours. Because we have better grinding techniques. We can calcine limestone instead of the quicklime that the Romans used. Our concrete is truly superior. However, we put reinforcement in concrete, which often limits its lifespan. So that's where the problem lies in terms of the lifespan of concrete. Even if we had built the Pantheon with reinforced concrete, we would have had to rebuild it 20 times due to concrete rot. So, on the one hand, we need to make concrete that lasts a very long time, and the Romans did that quite well, because they also used self-healing, and we can still make improvements in that area.

[10:13] Service life extension and implementation quality

Bob Lambermont: It's not just about adding self-healing technology. It's also about the correct execution of concrete pouring, which is often neglected. Over-vibrating, over-curing. These are simple things that can also greatly increase service life.
Niki Loonen: Yes, absolutely. The quality of the workmanship is extremely important in order to achieve a long service life for concrete. After-treatment is actually something that is not properly standardized. I'm not really in favor of standardization, but when you see that something like after-treatment is not being done properly, you might think that there should be a rule for it after all.
Olivier Suerickx: No, but that's true. And after-treatment, sometimes that's part of it. Not enough attention is paid to it, but not treating it properly disrupts the hydration process. This results in cracks, premature cracks that could have been avoided. Especially if steel is still being used today, everyone is already tearing their hair out, just after the concrete has been poured. And then what? And then there are other costs, other issues that you have to deal with. So after-treatment is an important factor.
Bob Lambermont: Yes, indeed, on paper, concrete can be fantastic, very well specified, the right mix, beautifully made in the concrete plant, arrives at the site, and then during the execution of the concrete, it can all go wrong. And then, yes, how much is the paper actually worth? Yes, then we have to see what we have built and what it complies with. What is actually the performance of the structure that is important?

[12:02] Life cycle thinking and deferred maintenance

Niki Loonen: Yes, back to this point again, if you look at lifespan. In the Netherlands, we build for lifespans of 50 to 100 years when it comes to concrete. And we see that, for example, Rijkswaterstaat currently has an enormous task ahead of it just to maintain the infrastructure. You are both from Belgium. There, you can also see, so to speak, from the infrastructure that there is simply a bit of overdue maintenance. And in the Netherlands, we are less affected by this. But yes, the task at hand is enormous.

And actually, it's very strange that we see that what we built in the 1960s and 1970s is now pretty much at the end of its useful life. And that we're not actually doing any better or smarter now than we did back then. So, in my opinion, we really need to think much more carefully about how we can ensure that what we are building now, which is exposed to the elements, can indeed last indefinitely, as the Romans did. Lessons can be learned from the past. Yes, and the resources are there.

You can take concrete technology measures, you can take implementation measures, you can add innovative chemical technical additives such as a self-healer. You can alternatively reinforce with basalt fiber or with prestressing protected in plastic liners. There are many ways to achieve endless durability, or unreinforced as the Romans did.

[13:54] The technology already exists—but we don't use it enough.

Roel van Gils: So the technology for more sustainable construction already exists, but we just don't apply it enough?
Niki Loonen: No. And that also means that the technology needs to be scaled up. Because you can't just go from day one to day two to something new. You really have to go through entire processes to do that. You need pilot projects. You have to scale up your production. You have to align your standards and regulations with that. So that takes time.

Conducting pilots also serves a very important function: to demonstrate what is possible. And only after a number of pilots have been conducted will a guideline organization such as CROW say: interesting, it is now being applied so often, let's write a guideline for it. And that's how you take those steps. But the techniques are there, and scaling up is what we are going to work on.

Roel van Gils: Olivier or Bob, perhaps you could introduce a technique for that?
Bob Lambermont: You mentioned the comparison with solar panels. Thirty years ago, that made no sense at all in our region and the cost was far too high. And now you see them everywhere because they have been scaled up and there is enough volume and demand to make them profitable. Technology has also advanced, so we are in the midst of that evolution. A very exciting story, a very interesting story.

[15:23] Self-healing concrete – how it works and examples of its use

Roel van Gils: And when we look at self-healing concrete, can you give an example of its application or describe how it works?
Bob Lambermont: Yes, self-healing concrete has been around for much longer. It is already widely used. It has obvious direct benefits in terms of service life and permeability. This means you can actually avoid using a number of other techniques for underground structures, such as membranes. You can work with less excavation if you add this self-healing technology to the concrete. And then you actually give the concrete a number of qualities for which we currently have solutions with additional materials. And then you actively incorporate the quality, the result of waterproofing membranes, for example, into the concrete.

Niki Loonen: Yes, an additional advantage is, for example, watertightness, as we now use quite a lot of reinforcement to control crack width. This is actually for both service life and watertightness. Take a tunnel construction as an example: in the past, these were reinforced with around 150 kilograms per cubic meter. Nowadays, that figure is above 200, 225 kilograms per cubic meter. This is purely because we are accepting less and less crack width.

So if you know that self-healing can repair cracks, you can allow for a little more crack width and therefore use considerably less reinforcement. So if you apply self-healing, and in some situations I would also recommend combining it with a shrinkage-reducing additive, you ensure that both the cause of crack formation and the extent of the cracks are reduced. You supplement that with a self-healer and then you actually get concrete that you almost only need to reinforce for the force effect. And there are quite a few structures that only need half or a third of the reinforcement for the extreme limit load compared to what is currently standard. With technology, we could reduce that.

[5:43 PM] Revolution or evolution?

Roel van Gils: So is it more of a revolutionary or an evolutionary step for the sector?
Niki Loonen: Personally, I believe more in revolutionary changes. When people enter a building, they must be confident that it will not collapse. That structural safety is important. Investors invest in buildings worth 30, 40, 50, 100 million. They must be confident that such a building will remain standing for 50 years, without extreme maintenance costs.

So you introduce changes step by step: tomorrow, for example, we're going to do a test pour with self-healing concrete in a basement wall. And we haven't removed any reinforcement yet. First, we need to gain experience. Will the implementation go well? A year later: will that wall still be in good condition? Maybe even better? Only then can you take bigger steps in the next project.

That's why I call it: evolution in pilots, revolution in end result.

[19:06] Risks of self-healing concrete

Roel van Gils: And what are the risks, exactly?
Niki Loonen: The risk with self-healing is that it may not be effective. It is interesting because when you get involved in projects, the question is: we want innovation. And then immediately: what are the risks? I appreciate that some products do indeed involve risks. However, the unknown unknown is the most difficult.

When it comes to geopolymer concrete or basalt reinforcement, I wouldn't dare say that there are no more unknown unknowns. But with self-healing, the main risk is that it might not work. And then you're back to where you started. The chances of it working are high, though.
Olivier Suerickx: I mainly see that we still focus too much on crack width. But a self-healer doesn't just work on cracks: it works on the entire capillary structure. It contributes to extending service life because it stops harmful intruders.
Niki Loonen: Yes, the pores become denser. Chloride penetration, frost damage—everything is slowed down. Actually, it should be standard in infrastructure.

[20:43] Self-healing in the entire concrete structure

Olivier Suerickx: I also see that, when it comes to self-healing, we still focus a lot on crack width or crack formation in general. But actually, it's not just about cracks or future cracks that could occur. The technology is an active system that continues to react as soon as water enters. But the technology also works on the surface, across the mass of the concrete, and in the capillaries in the structure of the concrete.
Roel van Gils: So you're saying it contributes to a longer lifespan?
Olivier Suerickx: Yes, it's not just protection against cracks, it's protection across the board. It ensures that negative influences are blocked.
Niki Loonen: Yes, what it actually does is seal the pores in concrete. This greatly slows down the penetration of harmful substances. This ensures a much longer service life, even without reinforcement. Frost damage, chloride penetration—all of that is slowed down.

[22:11] Why self-healing should be standard practice

Niki Loonen: It's actually quite strange that we don't just add self-healing as standard to infrastructure. It's a bit like: if it doesn't help, it doesn't hurt. And the chances that it will help are high. The renovation task is now so big that you would say: don't add even more objects that will soon require maintenance again, when you can limit it.
Bob Lambermont: In practice, we have seen a sharp increase in demand for port infrastructure and quay walls in recent years. The specified service life is often 50 years, but in practice, these structures sometimes do not even last 20 or 30 years. This has led to a search for sustainable solutions that limit maintenance and operational costs.

[23:35] CO₂ savings: new construction versus existing construction

Roel van Gils: The greatest CO₂ savings are not achieved through new construction, but through the preservation and restoration of existing structures.
Bob Lambermont: It depends on both sides. How can you make existing structures last longer? Self-healing technology can also be applied to existing structures. But they must be in good condition or restored to good condition. This raises the question: does renovation make sense, or should the structure be demolished and rebuilt?
Niki Loonen: There is potential for a major impact on new construction. But demolishing something to rebuild exactly the same thing is obviously absurd. Good maintenance and smart renovation are direct sustainability gains. But that alone will not save the 100,000 homes per year. We need both: renovation and construction. And construction is becoming more complex, not simpler.

[26:17] The lifespan of concrete is primarily an organizational problem.

Roel van Gils: The lifespan of concrete is often not a technical problem but an organizational one.
Niki Loonen: I completely agree. It starts with the client's request and our standards framework. Concrete is now designed for a lifespan of 50 or 100 years. But we are building a world that should ideally last for centuries. Look at the Binnenhof: it was never designed to last 50 years, but it is still standing.

If you build a concrete facade and concrete rot develops, while the installations are also worn out after 40 to 50 years, then the entire building becomes unattractive. Then we say: just tear it down. That is a mistake in thinking.
We should build things that, like the Pantheon, can in principle last forever—with renovations when necessary, but without fundamental degradation of the structure.

[28:17] Self-healing concrete is no longer a dream of the future

Roel van Gils: So the conclusion is that self-healing concrete is no longer a dream of the future.
Bob Lambermont: Certainly not. It is already being used for basements, underground structures, water pressure, and maritime infrastructure. You replace membranes with active technology. And you speed up the construction process.
Roel van Gils: Can you give some specific examples?
Bob Lambermont: Yes, for example, tunnels with shotcrete that incorporates self-healing. You skip entire steps in the construction process, such as applying PVC membranes. That saves weeks of time. We have also applied it in tank projects: cracks closed automatically in 4 weeks instead of 6. And even 45 additional cracks turned out to be completely sealed. That proves that it works.

[36:04] Sustainability demonstrably extends service life

Roel van Gils: A structure is only sustainable if it demonstrably extends the life of the construction.
Niki Loonen: You build a tent or a palace. That's my philosophy. A tent consists of parts that are replaceable. A palace has to last forever. Do you use secondary raw materials? Then you reduce the environmental impact, but you don't necessarily extend the lifespan. That's why we have methodologies such as LCA and MKI. They're not perfect, but they're the best we have.

Roel van Gils: And what role does self-healing concrete play in this?
Bob Lambermont: It significantly extends the service life. The costs are minimal compared to the total investment. If a technology can extend the service life by decades, then the answer is simple: proceed.

[39:30] Construction in ten years' time

Roel van Gils: What will construction look like in ten years?
Niki Loonen: If it were up to me: we are in the midst of the chaotic phase of the transition. Technology is advancing, old technology is dying out, standards are changing, chains are becoming bogged down, innovations are colliding. I love chaos. But after chaos comes clarity. In ten years' time, we will be much further along, but the journey there will be intense.
Olivier Suerickx: All the technologies already exist. All we have to do is apply them. Step out of our comfort zone.
Bob Lambermont: We must dare to set higher standards. Build beautiful structures that are also sustainable. The openness to new technologies is already there.

[43:04] The joint assignment

Roel van Gils: So the conclusion is clear: we just have to start applying it. The technology is there. Where there's a will, there's a way.
Niki Loonen: We could have started yesterday. But if that didn't happen, let's do it tomorrow.

[43:31] Closing remarks

Roel van Gils: Thank you all for your presence and this inspiring conversation. Olivier, Nicky, Bob—and listeners: thank you for listening. Until next time.