Blog March 19, 2020

Do Wireless Concrete Sensors Replace Concrete Cylinder Tests?

Answering this question isn’t as easy as you might think. Today, almost every industry is reaching a fork in the road when it comes to technology adoption. Some are more open to embracing these new advancements both to stay above the competition and prepare for the future. Other industries however have been practising their methods for such a long time, they’re hesitant to flip the script and introduce something new into their processes. 

Construction happens to be one of those industries. 

For over 180 years, concrete cylinder tests have been used in construction to determine the compressive strength of concrete. The process of lab-testing concrete samples taken from the project site has been – for lack of a better term – set in stone as the industry standard. Implementing an entirely new method of measuring concrete strength is like trying to teach an old dog new tricks. It’s not necessarily impossible, but the transition will take time. 

Tying that back into the main question then, the answer is both a “yes” and a “no”. Let’s dive a little deeper and find out why.

The Current

The idea behind concrete cylinder testing is simple. A sample of the mix is taken from the site and compacted within a cylindrical mold. The mold is transported to a lab where they run a series of tests to find out its overall compressive strength. The whole process is done multiple times throughout the concrete curing stages to ensure that the strength and maturity of the slabs progress according to the project schedule. Tests are usually performed 3, 7, and 28 days after pouring, but other circumstances may require more in between those times. 

Compressive concrete cylinder tests follow the ASTM C39 standard which consists of applying a compressive load on the axis of each cylinder at a predetermined rate until failure occurs. The applied force that’s recorded at failure is then divided by the cross-sectional area of the cylinder to determine overall specimen strength. That calculation is used as a basis for everything including quality control, mix design, and on-site pouring location. 

Cracked concrete cylinders after testing. The force recorded at the breaking point is divided by the cross-sectional area of the cylinder in order to determine overall strength.

The biggest problems with cylinder tests are that they’re time-consuming and not completely accurate. With the demand for construction projects reaching an all-time high, the existing concrete strength testing method is starting to become a major bottleneck for project timelines. Sample collection, transportation, and testing time can add up to weeks of waiting before the results come in. On top of that, compression testing is done in a controlled lab environment where external weather or climate conditions aren’t taken into consideration. It’s for this very reason that strength testing occurs so frequently throughout the curing process and incurs significant delays to the overall project schedule.

But in today’s technology-driven market, there’s a new method that can bypass cylinder testing entirely and they come in the form of wireless concrete sensors.

The Future

The recent advancements in technology over the past few years – known better as “Industry 4.0” – have given us the tools to discover more information about materials, be they natural or man-made. Wireless concrete sensors have emerged in the market as a means of accurately monitoring a concrete slab’s internal and even external parameters. Factors such as concrete temperature, maturity, concrete strength, relative humidity, and evaporation rate can all be measured in a single step using embedded sensors rather than through external testing.

Concrete sensors are designed to be placed within a concrete slab prior to pouring. Their high-efficiency power usage and on-board battery allow these small devices to stay running for very long periods of time, well past the average construction project time. The data they collect is sent to your mobile device over the air rather than through troublesome wires, which means you can collect vital information about your slabs from multiple concrete sensors with the touch of a finger.

Wireless concrete sensors can be embedded within a concrete slab prior to pouring. Their low power requirements and long-lasting battery life let them record and transmit concrete data for long periods of time.

But in today’s climate, data collection only scratches the surface of what’s possible. The true benefits of this new technology emerge when that data is introduced to advanced analytics software. Pairing Artificial Intelligence with complex algorithms, these tools integrate with your project scheduling system to optimize the overall timeline based on when your concrete slabs are cured. The data collected from wireless concrete sensors help the software generate accurate estimates of concrete strength based on ASTM standards, effectively eliminating the need for costly and time-consuming lab-based cylinder tests.

It’s clear then that wireless concrete sensors bring the construction industry closer to the future. Solutions are readily available to help project managers make the most of their schedules by giving them full visibility into their concrete slabs. So why hasn’t the industry adopted them yet? 

Well the issue isn’t from a purely technological standpoint. It runs a lot deeper than that.

The Underlying Issue

“If it ain’t broke, don’t fix it.”

Construction is tethered to global regulations and industry codes. The American Concrete Institute (ACI) and the American Society for Testing and Materials (ASTM) are just a few of the major regulatory bodies that dictate how the industry should be run throughout every sector. These organizations have been around for a very long time and have set tried-and-trusted rules in place to ensure that projects are completed to the highest standards. 

In the case of cylinder testing, the method is already surrounded by a mature market and infrastructure. Labs, testing equipment, experienced technicians, cylinder mold suppliers, and logistics services are just some of the individual players involved in performing a single concrete strength test. Introducing an entirely new data-driven testing system that completely bypasses the existing practise is a drastic change which – in an industry known for being very hesitant in accepting innovation – faces a lot of pushback from all parties involved. 

In recent years though, we’ve seen the construction industry soften up to the idea of having tools in their arsenal to help save costs and finish projects faster. Bringing wireless concrete sensors into the conversation is a step in the right direction towards industry-side adoption.

The Verdict

Like we said at the beginning of this blog, the answer to whether or not wireless concrete sensors replace cylinder testing is – at least for now – both a “yes” and a “no”.

Yes, wireless concrete sensors CAN be used in place of traditional cylinder tests. The data they collect on-site is much more accurate and – when integrated with advanced software analytics – can generate better estimates on concrete strength and curing time. What’s more, is that all of that happens on-site without any need for unnecessary time spent on sampling and testing. But at this point the industry doesn’t seem ready to wholeheartedly accept them with open arms.

For now, the major focus of this new technology is purely on project optimization. Instead of replacing it entirely, wireless concrete sensors can streamline the cylinder testing schedule. Using the collected concrete data to generate an accurate timeline of when testing needs to occur, project managers can save money and time spent on unnecessary testing, while maintaining the confidence that their slabs are meeting industry standards and project requirements.

Interested to learn how Wireless Concrete Sensors can help with your next project? Schedule a call today and find out how AOMS can help!