Latest / Internet of Things with Fexingo: Connected Devices, Sensors, and Industrial IoT / How IoT Sensors Track Concrete Curing in Real Time
Transcript
- Lucas: When you think about IoT sensors, you probably picture smart thermostats or warehouse trackers. But there is a massive, old-school industry where connected sensors are quietly preventing multi million dollar failures, and most people never see it. Luna: Let me guess — concrete. Lucas: Exactly. Poured concrete is the single most used building material on earth, and until very recently, contractors had almost no real-time data on whether it was curing correctly. They'd pour it, cover it, and just wait. Luna: Wait for it to harden, you mean. But the science of curing is way more specific than that, right? Lucas: Way more. Concrete doesn't just 'dry' — it undergoes a chemical reaction called hydration. And that reaction needs the concrete to stay within a specific temperature range — roughly 50 to 85 degrees Fahrenheit — for days. If it gets too cold, the reaction slows down and the concrete never reaches its design strength. If it gets too hot and dries out too fast, it cracks. Luna: So the old approach was basically hope that the weather cooperated and the crew didn't mess up the timing. Lucas: Pretty much. The standard specification just says 'keep the concrete moist and above 50 degrees for seven days.' But you have no way of knowing if every spot in that pour is actually at the right temperature. A concrete slab can vary by 20 degrees from center to edge on a cold day. Luna: And that's where IoT comes in. You embed sensors right in the pour. Lucas: Right. Small, battery-powered sensors — some are disposable, some have Bluetooth or LoRaWAN — that you literally toss into the wet concrete and they report temperature, humidity, and sometimes internal stress every few minutes. One of the most used ones is called the SmartRock sensor from a company called Giatec. Luna: I've heard of that. Canadian company. They started out focused on winter concreting in cold climates. Lucas: That's exactly where the market first took off. In Canada and the northern US, if you pour concrete in November and it freezes overnight, you could lose an entire foundation. A single sensor costs maybe 30 to 50 dollars, and it saves you from tearing out a pour that's worth tens of thousands. Luna: There was a case I remember from a bridge project in Tennessee. A highway bridge over the Tennessee River, I think. They used these sensors because the schedule was tight and they couldn't afford a re-pour. Lucas: Yes — that's a great example. The bridge was part of a state DOT project near Knoxville. The contractor embedded sensors in the pier caps and deck segments. And here's the concrete — pardon the pun — benefit: instead of waiting the full seven days to test cylinders, they had real-time strength data. They could know within 48 hours whether the concrete had reached 70 percent of its design strength, which is usually the threshold for removing forms or loading the structure. Luna: And they caught a problem on one of the cold-weather pours, didn't they? Lucas: They did. A cold front moved in overnight, and the surface temperature of the pour dropped to 38 degrees. The sensors alerted the foreman's phone by 3 AM. They deployed insulated blankets and portable heaters, and the concrete stayed within spec. Without the sensors, they wouldn't have known until the next morning, and by then the damage would've been done. Luna: That contractor estimated they saved around four hundred thousand dollars in potential rework and delay costs on that one project. I remember because it's a rare case where someone actually published the numbers. Lucas: Exactly. Those numbers matter because they shift the conversation from 'nice to have' to 'why wouldn't you use this?' The Tennessee DOT now requires wireless maturity sensors on all bridge decks over a certain size. That's a policy change driven by data. Luna: And it's not just bridges. The same tech is used in high-rise concrete cores, in tunnel linings, in dam construction. Anywhere the cost of failure is enormous. Lucas: Right. And there's a second layer: machine learning models that predict strength curves based on the temperature history. Instead of just logging data, the system can say 'this concrete will reach 4,000 PSI by hour 72, not hour 96.' That lets contractors strip forms earlier and start the next pour faster. Luna: Which saves time and money, and reduces the carbon footprint too, because you're not over-curing. Lucas: Exactly. And that brings us to the bigger picture: the construction industry is moving from prescriptive specs — 'do it this way for this long' — to performance-based specs — 'prove the material meets the requirement.' IoT sensors are the tool that makes performance specs practical. Luna: It's one of those quiet revolutions. No flashy headlines, just fewer cracked foundations and collapsed formworks. Lucas: And honestly, if today's tech conversation gave you something usable — maybe you're in construction, or you manage capital projects — and you found it worthwhile, there's a simple way to keep this show ad-free and independent. Luna: Yeah, we don't run commercials, and we'd like to keep it that way. Lucas: So if today was worth a coffee to you, that's the link: buy me a coffee dot com slash fexingo. Low-key, no pressure. It genuinely helps us keep digging into these stories. Luna: Agreed. And now back to concrete. So what's the next frontier for these sensors? Lucas: I think the big push is toward fully wireless, self-powered sensors that last the life of the structure. Right now most sensors are either disposable or have batteries that die after a few years. But there are prototypes using energy harvesting from the concrete's own thermal or mechanical strain. Luna: So you embed a sensor when you pour, and it reports for decades. Lucas: Exactly. Imagine a bridge that continuously reports its internal health — not just during curing, but for its entire service life. That's structural health monitoring, and it's the next logical step. Luna: And it meshes with the whole digital twin concept. You have a virtual model of the bridge that updates in real time based on sensor data. Lucas: Precisely. Some airports and stadiums are already doing this. But the holy grail is making it cheap enough for a two-lane county road bridge. The sensors themselves are cheap, but the installation, data management, and analysis still cost money. Luna: Still, the trajectory is clear. Ten years from now, pouring concrete without embedded sensors is going to seem as reckless as pouring without rebar. Lucas: I think that's right. And the interesting thing is, the tech is proven. The barrier is just adoption inertia. But every time a contractor avoids a re-pour, that inertia weakens a little more. Luna: So for anyone listening who's in construction or facilities management — the sensors exist, the case studies exist. The question is just whether you want to be the one who catches the problem at 3 AM or the one who pays for the re-pour. Lucas: Well put. That's the kind of concrete decision that IoT is making easier every day.