Concreting in Oceania regions comes with its own set of challenges unique to that specific region. Adapting to these challenges can be difficult for workers who have either little or no experience working in that region.
Our presenter, Matthew Denton, talks about how Giatec can help your company with concrete temperature monitoring in this exclusive on-demand webinar.
Channel Manager, Giatec Scientific
It is a bright and sunny morning down here where we are presenting our webinar today. Today we will be talking to you a little bit about monitoring concrete temperature in real-time. Thank you very much for joining us. And I know there is still a few more people coming in to join us and looking forward to having them with us as well. But firstly, I’d like to welcome you all and thank you for making the time to spend a few moments with us today as we talk about real-time concrete monitoring for temperature. We’ll dive into a little bit of strength as well, but let’s jump into it.
First, I’d like to do a quick introduction to our company. Giatec is a company that’s been around since 2010. We’ve existed in the concrete testing industry and with the vision to revolutionize the concrete testing industry, we have worked very hard to bring the latest and the greatest technologies to the market out there. So we’re looking forward to doing that, and of course today we want to focus on our concrete temperature monitoring.
I’d like to start us off this morning just with a quick little video that we have got about our company, just so that you have an idea of who we are. And then I’ll jump into a little bit of orientation with regards to today’s webinar and what we will be doing. Alright, so let me jump into the video quickly, I’d like to share that with you and then we will jump into our webinar for today.
Video: “Welcome to our modern world. Vast expanses of megastructures designed and engineered to keep us safe. Give us power, expand our horizons, and bring us joy. Centuries of human innovation built on a foundation of concrete, a foundation that has been laid with aging techniques, leaving infrastructures that could last for thousands of years, crumbling after 50. At Giatec, our mission is to revolutionize the concrete industry. With dedication to creativity, passion, and integrity, Giatec is leveraging the latest in research, tech, and artificial intelligence to create leading edge construction solutions. Our suite of smart testing concrete products, combined with our easy-to-use software, give you real time data on concrete, curing, hardening, humidity, and structural performance over its service life. Giatec is committed to a world-class customer experience, providing training, support, and access to our knowledgeable team of concrete experts. At Giatec we will never stop innovating, bringing cutting edge solutions to century old problems. Allowing you to build concrete structures faster, safer, and more economically. Giatec, revolutionizing the concrete industry.”
Right, and without further ado let’s jump into today’s webinar. Alright, so today we’re going to talk about monitoring our concrete temperature in real-time. Quick start, an introduction to myself. That’s me, Matthew Denton. I am the international channel manager for Giatec. I look after the Asia, EMEA region, so everything essentially East of the Americas falls under our International Division. And I’m happy to present to you our webinar today. I’ve been in the construction industry since about 2002. I’ve always focused around concrete form work and of course with Giatec for the last few years. So, I’m very happy to present to you our vision today.
Our vision at Giatec is to revolutionize the construction industry, our goal is to provide that in-depth information and knowledge to the entire concrete lifecycle. So, from the batching stage to the pouring stage, the curing stage, and then even the long-term monitoring of your structural assets as well. The idea, of course, is to use the technology that is available to us to be able to solve some of the challenges and the problems that we are faced with in our construction market today. If we look at our coverage, and this map needs a little bit of updating cause the world has gotten a little bit greener since we created this. But as you can see, we’ve got quite a broad coverage. We’re doing really well with SmartRock® specifically, we’ll talk about that a little bit later. It has been accepted throughout markets across the globe, and we really see the benefit that that is starting to play. Specifically, today we’re talking about temperature monitoring, and we’ll talk a little bit about the SmartRock3 which has certainly changed the game a little bit as well with regards to concrete monitoring and temperature.
So today there’s four sort of main factors that I’d like to cover in our webinar today. The first one is obviously heat evolution in concrete. Then we’ll talk about why is it important for us to monitor concrete temperature? And then we’ll talk about how do we control concrete temperature? What are some of the actions we can take to make those controls. If we’re monitoring the concrete temperature, and we know that it’s doing a certain thing, do we know what we can do there to mitigate any of the risk that we may have, or any of the issues or the challenges that we may be facing? Alright, then of course the other thing that we’ll be talking about today is how to monitor your concrete temperature in real-time, and what are some of the options that we have available there to us today.
Alright, so why is it important to monitor concrete temperature? Now this may seem like a fairly obvious question, but it’s certainly one that is worth delving into a little bit of time. You know, we know as people in the concrete and construction industry that the temperature of the concrete has a big impact on the quality of the concrete. So, one of the things that we’re always concerning or considering is we do not want the temperature of the concrete to be too high, or too low. Now, depending on what market you in, and depending on where in the world you are and your climate, you may have both problems, you may only have the one problem. You may have the high problem or the low problem. And you know in the different markets we’re working in we see that when the temperature is too low, of course our concrete is not curing. When the temperature is too high, we have risk of cracking, shrinkage cracks, thermal cracking, and of course that is some of the damages that are as a result of that in our concrete. And when we look at some of those conditions and we talk about the effects of poor poured concrete temperature conditions, cracking, reduced strength development, reduced durability.
If we talk about shrinkage cracking, we know that that is a result on the surface of your concrete as the quick evaporation of water, typically to do with high wind, or if there’s a very high concrete temperature, or if there’s a very low relative humidity in the concrete. And that of course, is something that we’re seeing more and more play a role, another aspect that people are bringing in to monitor the relative humidity of the concrete.
So, if we talk about thermal cracking in a mass element, this was one of the other aspects that we spoke about. We know that when the temperature in different parts of the concrete are at different values, the rate of curing is going to create different moments on the concrete or different movements in the concrete. So, for example, in our little sketch here we see that we might have in the cooling side of the concrete, we might have that contraction taking place, and then inside with the heat and the core concrete temperature expanding and getting hotter than the outside, we might see that expansion taking place. I’ll share this presentation as well; I will send this out for everybody. But of course, this is where the issue is, when there’s large, quick temperature differentials between the core element and the surface element, we can see that that can result in thermal cracking.
Another aspect is of course DEF. This is where we get early high temperatures, so if we’re seeing that once we’ve poured the concrete within the 1st 24-48 hours, we see that DEF takes place. And this is typically the expansion and cracking of concrete associated with the ettringite.
Alright, if we talk about produced development and durability, this was the other aspect. In hot weather, when we have that early high strength development, but oftentimes that results in a less gain strength in the later stage. So, if that early gain comes too quickly, too fast, we know that later on we could be losing durability of the structure overall. And of course, that makes for a weaker concrete, which is also more permeable, and of course more susceptible to corrosion and deterioration.
When we have cold weather, if the concrete freezes and it is still fresh, it will reach MPA. But it can have still a reduction in up to 50% of the ultimate strength. So again, whether you’re in extreme high or extreme low, both of these environments will provide a threat to the long-term durability and strength development of your concrete.
So, how do we control concrete? We know that we have a problem. We know that we have an issue that in high and low temperatures we have issues with concrete being too high and too low, and we know what the detrimental effect that could have on the concrete. So how do we go about to control the heat in the concrete? So, let’s talk about our timeline. So, we pour our concrete, we had maybe perhaps a little bit of a drop in the concrete temperature, that cooler temperature from the concrete that is fresh. And then of course, as the chemical reaction starts kicking in, the cement and aggregates start bonding, forming that concrete that we know, then we start getting that heat of hydration. We see that that spike comes up a little bit, and then of course that will start to plateau out as the chemical reaction wears off and the heat dissipates, and then we’ll see that we get a normalization of the temperature, the concrete temperature. So in the beginning, that initial temperature, that will be low. And then we have the extreme maximum temperature, and it’s in this area here that we refer to as the heat rise, and this is where we need to worry about our concrete temperature and controlling their temperature. These are the extreme temperatures that we’re looking to reduce. Of course, we all know in cases where we’re monitoring temperature already, the key factor is temperature differential. One of the key reports that we have within our SmartRock and Giatec 360™ platform is that temperature differential, that automatic graph that can be generated between two points. Because we’re measuring typically the surface, which will be the coolest point of that concrete or that mass element, and we’re measuring the deeper point or the core of that element to get that higher temperature.
Alright, so, mitigating improper concrete hydration temperatures. So again, we talk about that hydration, heat of hydration of the concrete in that initial temperature gain, and of course, that initial strength gain. There are three main factors that we could use there to mitigate that heat rise, or those hydration temperatures. Of course the first one, and this is definitely the most important, this is mix design. What we want to do here, is we want to make sure that we are designing our concrete mix for the purpose that it is required. If we’re doing a mass concrete element, we need to be aware we have that cool concrete temperature that could increase rapidly and that could get to very high temperatures, we need to account for that in our mix design. Of course the second option is external controls, so thermal blankets, heating, cooling. We’re having some very interesting conversations with some ice plants, you know companies that are producing ice plants. You know we see all sorts of exciting technologies coming out there, helping battery plants cool their aggregates, cool their water, do various things to try and keep that initial temperature low. But of course when we’re talking about on the concrete side, on the placed concrete, there are various things that we can do there to try and control that heat of hydration temperature. And then of course additives, we know we have accelerators, we have retarders, and everything in between. These are all different aspects that play a role in that and we certainly see that as an option to control that heat of hydration gain that we have right in the beginning.
Alright, so, if we talk about mix design, and we look at the different options that we have. Of course, one is our cement type, when we can choose the different cement types that are available to us. Those can certainly help mitigate that heat rise. When we have our cement content, so how much cement content do we have? What’s the blend? Do we have a bit of a mix of the cement content? This is meant to find the finesse as well. You know, what is the size of our cement that we’re using and what is that resulting? And then SCM as well. So, all of these aspects will have a direct impact on that initial heat rise. After the pour, to that top temperature, we know that they all have a direct effect on the heat rise. So this is the first one we said, mix design, these are some of the aspects that you can look at your mix design to control that heat rise.
If we look at external controls, then one of the couple of things that we can look at here of course is pouring at nighttime. We see that especially in our Middle East market, especially with Big Paws, we see them starting late at night, pouring through the night in those much cooler temperatures, so that ambient temperature is much lower. Then of course allowing for a more conducive environment to keeping the heat of that concrete down. Cooling aggregates, as I mentioned. You know, ice plants, batching plants, cooling the cement again. You know, having something in your batching process that’s cooling that cement, that’s keeping that a little bit cooler. And then ice, as well, of course. This is a big one we see as well, again, especially in the Middle East. And then a bit more expensive one as well is liquid nitrogen. So, these controls here, a lot of these controls here, are going to help prevent that initial temperature from being too high. So, as we pour in the concrete in that initial stage, we’ll see that we drop that temperature a little bit lower, and of course that will have an impact on how much higher the concrete temperature will be going from the start.
Alright, other external controls: blankets, tarps, some sort of insulation, heaters. Some sort of heating to keep the outside warm, you know, and obviously there will talk about that in a minute. As you remember that graph little bit further back, with the warm temperatures on the inside and the cooler temperatures on the outside. So, if you’re heating on the outside, or if your insulating that heat, you’re also raising the temperature of the outside area of your concrete. Water warmers, again, in your cooler climates, so on the opposite side. For example, like we have in Northern Europe as they’re batching and mixing their concrete, they’re warming up their water actually. Especially in those really below zero temperatures, to try and get that heating going. And then of course warmer aggregates as well.
So, as I said a little bit earlier, depending on where you’re sitting right now, in which climate you’re in, you’re going to have different controls to counter the ambient and the climate that is around you. And then of course the last one as well, the other way that we can control our concrete temperature is through as I mentioned, retarders and accelerators. And of course, this is quite exciting, you know, I’ve got many colleagues who are in the business of additives. And there all sorts of exciting new technologies with that when it comes to ways of accelerating the concrete or retarding the concrete. And of course, that will also have a direct impact on your concrete temperature.
Alright, I’ll take a quick moment here, if there are any questions. I don’t see any questions popping up in the chat, but if you have any questions, please do pop them up in the Q&A section. If there are any questions, you can either do it in the chat day very quickly and I’ll get that question, or you can of course open a new question and pop that in there and I’ll be able to answer those for you. Okay, great.
So, if we talk about temperature monitoring in our concrete, the first thing that we’re looking at is pouring temperature. So typically, we need to be monitoring that pouring temperature, again, you know this is a different requirement around the world, but we’re talking about a maximum of 24 and 28 degrees, of course, excluding mass concrete. But the temperature may exceed the daily ambient temperature by three to four degrees Celsius, unless cooling methods are applied. Alright, of course when the cold weather temperature drops below 4 degrees during their protection period. So, why are we looking at monitoring temperature? Why are we looking at, and what are the ways that we need to consider to monitor that concrete temperature?
So, a couple of aspects that are important when we come to this scenario, at that pouring stage. We need fast, simple, and accurate. It’s got to be real-time, so we can’t get the result of our pouring temperature 24 hours later, or six hours later, it has to be there and then. So, the moment at which we’re pouring, we need to be taking the temperature of that concrete so that we can act accordingly. Right, if we need to react to something, if the temperatures spiking, if the temperature is dropping, we need to make some sort of action there. And of course, to keep our concrete temperature at that pouring time within certain norms, within certain requirements, and certain regulations.
If we talk about the curing temperature, and this is of course that longer time period. So, after we poured the concrete, we’ve got the concrete in place, and now the concrete is beginning to cure. We need to watch those maximum and minimum concrete temperatures. There are certain limits that we have to adhere to, there are certain maximum differentials. These are things that are going to have a direct effect on the proper strength development as we mentioned earlier. These are during that curing time, this is also when we will prevent shrinkage cracking, where we can also evaluate in place concrete strength. We’ll get to that in a little bit of detail a bit later. But again, what is the solution that we’re looking here? Again, fast and easy, precise or accurate is important here, quick reporting so that we can respond to the information. Again unfortunately, in a lot of our markets around the world, we see the habit of okay we have to monitor concrete temperature. We monitor concrete temperature for seven days, and we give the report back on Day 7 to the contractor or your concrete subcontractor. It’s too late, the damage is done. And this is where we feel that you know it’s very important for us to have a temperature monitoring solution that will actually be quick and fast to give us that information that we need during that curing stage, not post curing stage. And of course protected as well, this is something we’ll talk about when we talk about some of the products that are out there to allow us to monitor concrete temperature, especially during the curing stage. But, if we’re talking about those prolonged times, we need that sample, we need that concrete temperature to be monitored, we need that device or whatever we’re using to monitor the current temperature to be protected so it’s not damaged. And then of course real-time might be required, but again, as I said, you know if you have quick reporting, fast turnover times on your reports, then certainly this is a factor for that.
And then we talk about long-term temperature monitoring, and this is where we’re looking at preventing that thermal cracking. So, beyond that early stage, a little bit further past the curing stage. Again, what do we need here? Multiple depths, it’s got to be fast, it’s going to be protected again, and of course we have to have efficient, quick reporting here. Very important for us to consider what we need in a temperature monitoring system when we are considering what we have to do. And of course, as you can see for the all these different scenarios that we have, typically we’re not going to implement a different system for each scenario, so we want a system that is going to cover all of that.
So, if we talk about that for a minute, what are the tools that are available out there today? And again, you know if you have any questions or comments so long, and I’d be interested to hear maybe you know if you are using something to monitor concrete temperature at the moment, what would it be? Feel free to pop that into the chat there? It would be interesting to know to get a feeling from the group today. What tools are you using to monitor your concrete temperature at this time?
Okay, so as you’re putting those in the group there in the chat there, let’s talk about some of the options that we have. We have the thermometer, and this is pretty standard. I mean, I think most of us have seen this, and especially in today’s day and age with Covid, there’ one of these handheld thermometers just about everywhere. Checking temperatures, and monitoring temperatures, writing your names down, signing the book. And so you know, checking that surface temperature of the concrete, commonly what this is used for. I’ve only used one of these for baking, or for painful cooking should I say. But I’ve never used one on the construction site, but of course this is one that you can also just slip into the concrete, get that concrete temperature. And then a little bit more sophisticated your thermometer with a datalogger recording points and so forth, and obviously getting your real-time temperature there as well.
When we go to the more longer-term monitoring, we have some other options. We have the wired thermocouple system, so this is typically where we have a data logger in place, there will be a wire running down into the point that we’re looking to measure, and this is of course just a standard thermocouple system. Either a wired system like this, where you just got the wires connected and getting that measurement and that reading, or you actually have some sort of device at the end where there’s some sort of intelligence possibly, connecting to a data logger.
Again, the issue here is that you know if we look at the options when it comes to this, you know we have a device on site can be a little bit complicated. Here you can see all the wires required, this was just for one pour. You know, in this scenario here they’re doing some match curing a little bit as well. In this scenario here, very complicated. And again, one of the things that we spoke about a little bit earlier, is that during the construction process, the one thing that we don’t want to do is we don’t want to lose the measurements that we’re looking for, we don’t want to lose those measurement points. And of course, one of the best ways we do that is by making sure the device that we’re using is a protected device.
So, let’s have a look at the next generation that’s available out there. We have got some wireless solutions, so this is a, you know, this is sort of the in between stage where it’s a wired solution connected to a device that can communicate wirelessly. Same here as well, so this would either be prepped to a more local signal and this one here would be possibly to a GSM signal. So again, you have the wire coming out of the concrete, the data is being collected here, and then transmitted over a network to a tower, and of course then that can go up to a cloud and as you can see here. And then another option would be where you actually have a hub on-site, and we see this happening fairly often now, a hub on-site wired solution transmitting.
So, this is sort of the next generation from their previous generation of the wired solutions. Then the introduction of the wireless option. Not truly wireless obviously, cause you still got a wire here, but of course that connection there. So here we don’t need to be actually manually downloading the data from a data logger, which is nice, but of course we could take that one step further and this is where I do want to introduce us to the SmartRock3. So here you can see you have the SmartRock3 device, completely embedded. Alright. With the cable going to the point that you need to measure. So, you still have that accessibility to measure the point in the concrete that you’re looking to measure. And then of course from there you’re transmitting to your smartphone, and your smartphone connected to the Internet as you normally are, and that then transmitting the data to a cloud. The other option of course, is to have a hub solution as well. So again, we have the wireless connection here, but again from an embedded sensor.
So just to show the difference, you know it’s important to distinguish this is that. Here we have some sort of device on-site that we are either having to monitor the battery on, or we’re having to clean, or having to protect it so that when we have all our foot traffic and things happening on site, that of course is not damaged. And of course, this is where our solution comes in, where we believe the future of monitoring concrete is. Is a completely embedded solution, which allows an open area here on the top. No hindrance to other concrete works or other works that need to take place on-site. And of course, allowing this very seamless connection to a hub, or to your smartphone, and then up to the cloud. Alright, and as you can see there, you know that’s kind of what you would expect to see on site. Looking at your phone, and of course the SmartRock embedded into the concrete there, no wires protruding, nothing coming out, nothing at the risk of being damaged or broken.
So, let’s look at some of the advantages of monitoring our concrete temperature. Of course, we have the quality control, we can control the durability of the concrete as well. We know what’s going to come out on the other side of it, and we can understand what impact we’re going to have on the long-term strength of the concrete. We can have control. Control over our program, control over our control methods. Those external control methods I spoke about, tarps, mix designs, when we go into accelerators and retarders. When we’re monitoring our concrete temperature, we have a clearer picture of how our concrete is performing, and that’s of course what we’re looking to do, and that’s what we’re looking to provide. The long-term data collection as well is of course very important. If we’re measuring the long-term data for the longer term, for our concrete temperature, we want to see what’s happening there. Again, we can get that advantage, and then using temperature for strength monitoring.
So, our next section is the introduction to concrete maturity. Now one of the things I mentioned sort of in passing previously is that if we are monitoring the concrete temperature in real-time, on a continuous basis, then we are able to determine concrete strength. And this is something that is new to perhaps some of you, it might be old hat to some of you as well, might be something that you’ve heard or seen before. But if we talk about maturity, what is maturity? Maturity is a method in which we can determine the concrete strength based on the temperature history of the concrete. So, if we’re monitoring the concrete temperature in real-time and continuously, we are able to determine what the strength of that concrete is through an equation which we call the maturity method.
Alright, so let’s go into that in a little bit of detail, again I will send this presentation out to you, you don’t make too many notes here if you don’t want to. But if we look at this, so let’s understand this basic concept first. The higher the temperature, the faster the curing of the concrete, the lower the temperature, the longer the curing time. So the ASTM that says that we can estimate concrete strength based on assumption that the samples of a given concrete mix attain equal strengths, if they attain equal value of maturity.
Alright, so another question is what is maturity? Alright, let’s talk about that a little. Maturity is a function or value which we refer to, which is based on degrees Celsius over hours. Okay this could be Fahrenheit as well, but I know that most of the market we’re talking to today is working with the metric system. So, if we are measuring the degrees Celsius over time, we can determine a value which we refer to as the maturity value of the maturity index. And every concrete mix has a unique, not batch, mix, mix design perhaps that’s a better way to clarify. Every concrete mix design has a unique maturity and strength relationship. And that’s what we’re looking to show you as well, is that by monitoring our concrete temperature in a continuous fashion, taking temperature every 15 minutes, having that accurate temperature history, one, we can determine the maturity relationship, maturity-strength relationship of a particular mix design. And then we can apply that to our poured concrete on-site. So once we’ve determined what the maturity strength relationship is of a particular concrete mix, we can then use that information to monitor the strength on-site.
Alright, just so that you know, this is not a new method that we have come up with or devised, it is a standard. It’s an ASTM standard, it’s an ACI standard, AASHTO standard, a lot of the DOT’s around the world actually are now compliant and conforming to maturity, and preferring maturity specifically for that early age. So if we go back to the standard, we go back to the definition, we talk about the early age strength. We also have a lot of EN standard. There’s an EN standard, there’s the NEN standard, there is a BS standard as well, that all refer to maturity. And we see this sort of adoption growing around the world.
Alright, so how does maturity help us? What’s the value of this? Well, firstly we have more control on your job site. You’ll have more accurate strength results. So when we’re pouring our mass elements, when we’re pouring our slabs, our post-tension decks, all of those. We’re going to have more accurate information based on the institute concrete, as opposed to the small sample that we take and put into a completely different environment. It’ll also give you a localized measurement of the concrete strength. So in other words, wherever you placing a sensor in the concrete, you will be able to determine the concrete strength in that location. So perhaps you’ve got a big slab that you’re doing, and you started pouring on the one side, and you finished pouring the other side, six hours later there’s going to be a strength difference between where you first started pouring concrete and when you finish started pouring concrete, and that’s of course very important for you to consider. Okay. And then of course, where you can save time and money with information and knowledge comes power. And with that knowledge and information you’re able to save time and money, and of course we can increase your safety as well.
I would like to just take a moment here to just go back here quickly. Alright so. Yeah, there we go. There are three ways in which we can monitor concrete temperature. The three ways that we are using right now is, we have our field cured specimens. So, these are specimens that we take on-site, we keep them on-site, and we try and cure them in the same conditions that are placed concrete, or our in-situ concrete is, to try and replicate that ambient temperature. Not a common practice everywhere, but certainly we’ve seen that in some markets.
Our lab cured specimens; these are the standard practice that most of us are adhering to. We pour our samples, we send them after 24 hours, we send them to a curing bath, or a lab, or a testing lab. They are kept there for a period of time, and of course then crashed at the different intervals. And then of course we have our maturity meters, so being able to use maturity to monitor concrete strength is one of our advantages here. We talk about that, but these are the three main methods that we have at our disposal right now.
What are the limitations of concrete cubes or cylinders depending on what market you’re in. Of course, inaccurate temperature conditions, delayed results, limited information, local variations, you know different places or making samples in different ways, and low visibility. Just to do as a quick example, and I don’t take too much time on this, but as a quick example here you can see a nice comparison between the three concrete situations, let’s say.
So the first one, if we start, let’s start at the bottom here. If we look at the first one, the red line here is our field cylinder or our field cube. And this is when we’ve taken a sample, we’ve poured it, we’ve left it on-site in that ambient temperature to cure, like the slab or the concrete element that we’ve poured would be curing. And so there we can see quite a drop off, obviously with a smaller element, the heat of hydration is not nearly as high, and also what we have is we have the fact that that sample is not going to gain as much heat as quickly, so we see the drop in sort of temperature. This particular example is of a bit of a cooler example, and we see then that sort of picks up a day-night cycle and follows the day-night cycle. So, on this particular project here, it was quite cool, it was in autumn I think, but the actual ambient temperature was quite low, so we see that drop.
Of course, the lab sample looks very different. The lab sample drops to the same temperature at pouring, which we expect, but of course the moment we take that and put that into our curing bath, it picks up to 23 degrees, 20 depending on where you are, but 22-23 degrees and it flatlines at that 22-23 degrees. Whereas, exactly the same concrete poured at exactly the same time on exactly the same site, but placed where it should be placed, as in the in-situ concrete or in-place concrete, we can see that the concrete temperature gain was much higher on-site. So as you can see in the 1st 24 hours it spiked up to over 36 degrees here, and that’s not unheard of if you’re measuring your concrete temperature during stage, that’s not unheard of, that’s not really a high number or anything like that, that’s standard sort of heat of hydration. But of course, we see it in the drop off comes quite quickly as the chemical reaction dissipates, and then we see that sort of ambient temperature kicking in, and again it sort of starts falling into that day-night cycle a little bit there.
Alright, so very interesting. What does that mean for us? That means that if you can imagine, and we apply this into a strength graph, what the strength graph will look like? Alright, so here’s a nice example and this is a bit more detailed, here we are to the sample. So, if we have a look at this, and we look at the maturity values here and you might not know maturity, so that’s fine, but here you can see you’ve got 2, 3 very different lines representing the same concrete as a result of the different temperature conditions that that concrete has been put in. So as you can see with the red line, which was the small sample on site, the maturity level sort of stays low here because that temperature never really got to any higher levels, and then it sort of fell into that 24 hour cycle. The blue line had a bit of a dip, obviously in the beginning, and then as it got into that bath, it just sort of shot straight up and kept climbing, climbing, climbing, climbing. Alright, whereas with the green, which is our actually in-place concrete, we see in the first sort of 3-4 days we see a faster gain in the maturity value here and then of course that plateaus a little bit out and ends up actually lower than the actual cylinders on-site.
Now this is very interesting because what does that look like on a strength graph? That’s what I want to show you next. If you have a look here, here you will see that in your first 24 to 48, even up to 96 hours. That the strength gain on-site is a lot faster than it is according to your cube. So, you can argue, and say well that’s good I’ll follow the cube because the cube is more conservative. That’s fair, that’s fair, but do we want to be conservative, or do we want to be accurate? And this is of course the reason what we talk about. Go back to our vision, revolutionizing the concrete industry, this is what it’s about. But look at the difference here in savings. Alright, we see that is almost a 20-hour time savings difference between the targeted strength in this particular site. So this was a post-tension deck, they were looking for their strength very quickly so they could tension their deck. And here you can see that they saved almost a full day on this particular project, for if they had you well in this case, they did. So they were using the SmartRock sensor, monitoring real-time strength based on the temperature, and you could see that they could actually take action a whole day earlier, and if they were just only looking at the lab samples. And then of course the field samples gave an even lower, so again, what are we looking at here? We’re looking at, this is an accurate representation of my strength gain on-site. This is an indication of my strengthening of my concrete, but in a completely different environment. And that’s what we talk about when we say real-time temperature and strength monitoring, this is where it comes in.
But I digress, we have gone a little bit far here, I’d like to share with you this particular project. It was a 54-floor project, they had three pours on each floor. They had a time savings here of 12 hours per pour, so they were conservative, they didn’t save a whole day, they saved like half a day. And half a day of those half of days of all the pours they were able to save, that’s 150 pours. They were able to save 1800 hours, which of course translates into 75 days. And this was very very interesting. So for them, of course you know we know how projects go, it’s not always about saving days about sometimes winning back days that we have already lost.
Alright. The second example that I want to show you, this is the same location, so previously I showed you if we measure the temperature and the strength in concrete in this sample, versus the cube, versus the field-cured sample, then we have very different temperature gains. Here I want to show you an example of when we have a slab, and we’re actually measuring the temperature at the same location in the slab, but at different depths. Alright, let’s have a look at this next example.
So in this example we have got the same location on a 20 centimeter thick slab, but at different depths. Alright, so if we have a look at this very quickly, we can see that you know here we’ve got a bit of a greater heat gain at the bottom because we have got our formwork there and we’ve got some obviously heater of hydration taking place. So not a very thick slab here, but have a look at what happened when we measured the difference between a temperature at 2.5 degrees. I’m sorry, I apologize, the lines on the graph are actually the wrong way around, but anyway. So if we measure 2.5 centimeters deep into a 20 centimeter slab, this is what the temperature profile looked like. So you can see it was sort of the spike at the pouring, it goes up to about 35 degrees, and then plateaus there for the first 24 hours. When we measured to the middle of the slab, so just 10 centimeters deeper alright, so that’s 8 centimeters, excuse me not even, seven and a half centimeter difference between the depth. And we’re not talking mass elements here, we’re just talking 20 centimeters, 200 millimeters. As you can see, a very different temperature profile okay. So again, I apologize that the lines are mixed up here, sorry the red line is representing this 10 centimeters, so that you see the strength of the temperature goes up to your 35 degrees and then sort of plateaus out, whereas your 2.5 centimeter actually stays quite low because it’s not as affected by the heat of hydration because of the shallowness, as well as the ambient temperature is having a big impact here. So we see that sort of keeping this temperature profile quite low.
What does that look like when we put that into a strength graph? So again, with maturity, we can tell you what the strength gain of these different elements, the different points in the same location where. So first we look at the slab in the middle, and we can see that after four hours when the temperature starts kicking in, we see that the strength gains starts picking up, picking up, picking up, and after 21 hours, we hit a strength of 30 MPA. Whereas for the 2.5 centimeter depth, we have a slightly different strength gain, so you can see the gain starts a little bit later. We see this sort of graph picking up here, you can see that the curve is not as aggressive as the deeper one. And of course the difference here being that just in those seven and a half centimeters, we see a four hour difference in the strength gain. So that top part of that slab was only reaching 30 MPA 4 hours later than the center of that slab. Alright, and that of course provides us with a bit of a safety window, because if we’re measuring the core, or if we’re measuring the surface, that gives us a bit of a safety window to work with there. And so therefore, if we are measuring the surface of the concrete, we know that that is going to be the slower one. Of course this isn’t a scenario where that ambient temperature will have that effect on it. Certainly there is the other option there is when we’re in a hotter climate, we could look at a slightly different scenario.
So I’d like to share with you very quickly, and I know we only got about 2 minutes left of the webinar today so I don’t want to take you take any more time then we promised we would. So I’d like to share with you the Giatec solution very quickly. I’m going to play a nice short video for you. It goes into the detail of the SmartRock 3, it’s a short video, 2 minutes long, and then we will stop there. I will stay online afterwards if anyone else has any more questions to ask. But again, I want to thank everyone for being here this morning for joining us today, spending some time with us. I will dive into this video and spend a little bit of time now on the Giatec solution, but I know we’re almost out of time. Thank you very much for your time, and I do hope you can stay by behind and ask some questions and I’ll be happy to make myself available for that.
Alright, great, thank you very much. Alright, so that was just a quick video on our SmartRock 3 version, and as you saw there very nice simple device, easy to install, you saw the size there, the scale. I have one with me here as well and you can see it. The SmartRock 3, this is the body, inside this body this is where we keep all the magic. There’s the Bluetooth antenna, the battery is here, the transmitter. obviously the Bluetooth transmitter, and as well as a secondary temperature sensor. The first temperature sensor is at the end of the cable, so by using this one sensor you can measure 2 temperature points, and therefore two strength points. You saw the QR code being used there to add the sensor to the project in our software. The activation of the sensor is very simple, we pull that cable out to activate the battery. So until then the battery is dormant, and then of course that nice rubber strap to do the installation as well.
Talking about adding the sensor to our software again, you can add, make, and edit all your projects directly on the app. You can break your projects up into different sections, and in those sections you can add multiple sensors. And of course there’s no limit here to the number of sections, the number of projects, or the number of sensors that you have under each section. You’ll have real-time data to your phone, so if you connect to the sensor you’ll have the real-time temperature right there and then as what it is. As well as a record of all the temperature points that its collected. So the sensor takes a reading every 15 minutes and logs that as a point, and then we’ll plot that onto the graphs for you. It will give you a temperature graph, a maturity graph, and a strength graph. The battery life as well, so coming back to the data recording, the battery life of the sensor is four months, and it has a memory of 60 days. So if you already doing temperature monitoring, you might be familiar with data loggers that have a battery that needs to be changed and so forth. Remember this is a completely embedded device so there’s no maintenance of the device post installation. Once you’ve installed it, the concrete is poured, it’s a lost device, but of course the advantages there that there’s no need to come back and change batteries and collect the data every one or two days. You can come after four months and collect all the data from the history there, because it would be available. But the moment that you do collect it all on the phone, and the phone is connected to the Internet, it will upload all that data to a cloud and so it would be accessible on our Giatec 360 platform.
Roxi she is the AI program, she can do a number of things. She’s the first AI program for concrete testing. She can do some suggestions on your pouring time based on the temperature history, she can validate your maturity mix calibration, and she can also have a look at your mix that you’ve got, your mix design, and she would be able to do a calculation on how you can reduce your cement content in your mix in order to economize your mix. So very exciting of course we’ll jump into that if we need some more information there.
Our Giatec 360 platform. This is of course the nice overview of all the projects that we’ve had in the last while, but what you would be interested in is that you can have a look quickly at your sensors, you can select your project, you can select multiple sensors and automatically it will calculate a temperature differential. Cause this is normally the key that we’re looking for when we’re monitoring temperature. Is the temperature differential above 20 degrees or not? If it is, then we do need to pay attention to the concrete or implement some controls to help mitigate that. An optional option here is the smart hub solution and this allows for remote collection of the data, so this will be left on-site, and it will manually or let’s say proactively collect the data from the sensors, so that is available as well if that is an option that you’re interested in. And then of course as ready-mix producers, we’ve got the SmartRock® Plus solution, which allows our ready-mix producers to have visibility on how their mixes are performing on-site. Alright, but unfortunately our time is up everybody, thank you so much for joining me today. Thank you very much for attending our webinar. And we hope to get some SmartRock onto some of your projects in the very near future.
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