Anyone who’s watched TV in the past year has seen commercials for a refrigerator that tracks its inventory to automatically update a shopping list kept via an app on the homeowner’s smartphone. Pretty neat, huh? Welcome to the Internet of Things (IoT), where everything in our lives – including concrete production and delivery – is connected to the Internet.
An August 2017 Concrete Producer article titled “Can Intelligent Equipment Make you Smarter?” explains how Graniterock, a century-old materials producer and construction contractor based in Watsonville, Calif., uses IoT to match batch and dispatch information with mixer location to improve deliveries, fleet efficiency, and mix performance. This is cutting-edge technology, but the edge is starting to cut even deeper. Telematics and specialty sensors are bringing the ready-mixed truck into the IoT world.
Until a couple of years ago, producers wanting to maintain quality after the truck had left the plant had to place all their faith in their driver and a small piece of tissue-thin paper: the delivery ticket. If water was added to the load at the jobsite or the contractor held the truck for an extended period, the driver was supposed to note that on the ticket. Needless to say, that didn’t always happen. It was as if the truck drove into a black hole that sucked up all knowledge about what happened to the concrete.
Today things are different. Devices are being developed that track what’s happening with the truck. By coupling that information with real-time communication to the cloud via data packet networks, producers can learn about any delivery problems before the truck returns to the plant. The question is, how do we unlock the Easter egg that’s in mixer trucks?
For those of you who aren’t videogamers, an Easter egg is special information displayed in a game or video when a secret set of actions are taken. The simplest example is clicking on the Google search logo on days when a special Google logo is displayed. On these days, clicking on the logo takes the visitor to a special webpage, displays a fancy animation, or starts a little game. A concrete mixer has Easter eggs, too; we just have to learn how to find them.
Instrumenting trucks isn’t new. GPS systems, combined with truck status systems, tell dispatchers where the truck is and estimate when it will return. Hydraulic sensors tell the driver what the slump is. The engine diagnostic port lets the maintenance department know about any problems with the truck.
But all of this is yesterday’s news. Four technologies are changing how concrete is delivered.
Driver monitoring
According to the U.S. Department of Transportation (U.S. DOT), more than 4,000 fatal accidents every year involve large vehicles such as ready-mixed trucks. To improve safety and reduce costs, new video technology is being combined with real-time GPS telemetry to monitor and improve driver skills. These systems provide a scorecard that tells the driver how he (or she) is doing and/or video feedback detailing areas for improvement.
In talking with the companies that sell these monitoring systems, driver response to the technology falls into three categories:
- Those who love it because it helps them become better drivers
- Those who hate it because they don’t like Big Brother looking over their shoulder
- Those who hated it until the technology proved an accident was the other guy’s fault.
Like GPS systems, driver monitoring is here to stay.
Electronic driver logs and vehicle inspection reports
Proper inspection, maintenance, and operation are vital to ensuring public safety as well as that of the mixer driver. That’s why the U.S. DOT made driver logs and vehicle inspection reports mandatory.
Paper logs could be massive, though, and often inaccurate due to human error. To improve accuracy, a provision in the federal transportation funding program signed in 2012 (Moving Ahead for Progress in the 21st Century Act/MAP-21) requires that an electronic log be tied into the engine diagnostic port to link driver entries to mileage, engine hour, and other readings. All this information can be sent to the office in real time to identify discrepancies and missing log entries. New devices and apps make the link between the diagnostic port and the driver log possible.
Electronic concrete delivery tickets
Before 2016, only one company provided electronic concrete delivery tickets. That's because, until then, ASTM C94, Specifications for Ready-Mixed Concrete, required tickets to be written, printed, or stamped. At the Committee C09 on Concrete and Concrete Aggregates 2016 summer meeting, members voted to allow electronic delivery tickets as well.
This was an important change for Federal Highway Administration and American Association of State Highway and Transportation Officials e-construction initiatives, which promote migrating all paper-based processes to electronic format. For many transportation departments, concrete delivery tickets were the last document to go digital.
Today, several companies, such as Command Alkon Inc. and Sysdyne, have software that generates e-tickets. After confirming delivery by signing the ticket via smartphone or tablet, the customer receives a PDF copy of the ticket via e-mail or website.
A number of disconnects between ticket capability and contractor needs exist, but these issues are being resolved. For example, many transportation departments require their inspectors to sign the ticket and note slump, air content, and concrete temperature on the ticket. Because C94 doesn’t require these bits of information, e-ticket software is being tweaked to allow such information to be added at the jobsite so public agencies can collect all pertinent information into a single database for easy retrieval.
Truck-mounted sensors
Almost any part of the truck that can be instrumented can report a process status back to the home office. Rollover detectors warn drivers of an imminent event or immediately notify emergency responders when one’s happened. Flow meters attached to the auxiliary tank record water being added. Load cells calculate the weight of the mixer drum and its contents to relay how much concrete remains. There’s even a new class of in-drum sensor that measures concrete characteristics in real time.
In-drum sensors are different from hydraulic gauges, which have been used to estimate slump for more than a decade with variable accuracy. The new generation of sensors extends into the drum and measures the load the concrete places on them as the drum revolves and the sensor is dragged though the concrete. This load can be related to the slump. The sensors can measure other factors as well, such as concrete temperature or the volume of concrete remaining in the drum.
This information is crucial to successfully implementing an ASTM C94 change designed to minimize how much concrete is sent to landfills. In January 2017, Committee C09 approved the use of returned fresh concrete (also called top-loaded concrete). This means that if a mixer returns with 2 cubic yards in the drum, the producer may treat the concrete, add new concrete, and ship the mix to a new customer.
The concept of using returned fresh concrete scares some people, but the process can produce excellent concrete when properly implemented. ASTM C1798, Standard Specification for Returned Fresh Concrete for Use in a New Batch of Ready-Mixed Concrete, codifies the process, which requires knowing how much concrete is being returned; how much water, if any, the customer added; and the returned concrete’s temperature.
What’s next?
These technologies are the tip of the iceberg. Over the coming decade, driverless trucks, cement hydration and strength development probes, 360-degree video monitoring, and a host of other sensors and applications will make concrete more predictable, usable, efficient, and cost effective. Who says a refrigerator is smarter than a concrete truck?
