Aggregate (AGG) is ~80 percent of ready mixed concrete (RMC) by weight. Variation from planned aggregate quality influences both plastic and hardened properties, yet testing is scarce in proportion to its importance. It’s fair to say AGG just isn’t feeling the love or attention it deserves.
If, like the Righteous Brothers song, “you’ve lost that lovin’ feeling” for AGG, emerging digital technologies can help. Imagine economically using optical digital technology combined with advanced, real-time analysis to continuously test AGG in-line during production. What would that mean for quality assurance (QA) and quality control (QC)? Why should it matter to you?
Taken for “Granite”
AGG’s surface area, driven by geometry, impacts the hardened structural properties directly through packing and plastic-state water management. Yet accurate AGG testing is more challenging than testing for other constituents; the variability and subsequent difficulty is much higher. Much more effort is put into reactive water control and admix management, even though AGG quality directly impacts both.
The American Concrete Institute recommends taking aggregate samples every 45-50 tons, which is approximately two inbound truck deliveries to the batching plant. The effort to grab, dry, sieve, and test a sample is so time-consuming, it’s likely the AGG is already batched before the results are known. Alas, even the most quality-conscious producer only pulls a sample for about every 1,000 tons due to these challenges.
Even if the testing process was simpler, the lengthy delay between test and results means the AGG used in any given batch can wildly vary from specification. This fact destroys our somewhat assumptive attitude about the consistency of AGG. The path to precision, like so many others, is incremental.
Incremental Improvement
Green materials company AlterBiota was originally formed to reduce the carbon footprint of RMC using a liquid admixture made with biochar, an end product of carbon sequestration that’s produced from biomass sources. The admixture not only sequesters carbon but also enhances the hardened material properties of RMC, thus further reducing the need for cementitious materials and their associated carbon footprint. A double win.
Building on this success, AlterBiota turned its attention to making batching more precise. This effort quickly led to tackling in-line AGG quality testing. Historically a neglected area, there have been few effective techniques to evaluate AGG quality as it is streamed into the weigh hopper for the batch. But reducing concrete’s carbon footprint to its fullest extent demands more precise batching—to do this, AGG must be tamed.
The company developed Digital Aggregate, a system that uses computer vision technology at the point of production to capture images of aggregate and analyze it in real time. The system is also available in a mobile version, enabling on-the-go quality assessments.
Finding the Missing Link
AGG quality evaluation is now much more accessible, thanks to huge advances in optical sensors, digital technology (including the super computer in your pocket), and cloud-based analysis. You can pull out your phone and take a picture of AGG at a stockpile and immediately receive quality metrics. More significantly, you can mount in-line optical sensors to monitor the AGG quality metrics during batching and get a digital snapshot of aggregate quality in real time.
While nothing is perfect, and purists may argue that traditional hand-analysis methods are more accurate, the real benefit lies in the ability to make immediate adjustments. If 10 percent of potential accuracy of analysis can be sacrificed for real-time corrections to the batch, the potential savings are huge. And according to Mark Masotti, the CEO and founder of AlterBiota, correcting just one or two loads per month can offset the cost of the company’s aggregate testing system.
INLINE REAL-TIME AGGREGATE DATA
Applying Industry 4.0 to Batching
Industry 4.0 integrates digital technologies like the Internet of Things (IoT), artificial intelligence (AI), and big data analytics into manufacturing and industrial processes. By connecting physical assets to digital ecosystems, manufacturing precision and accuracy is improved. Masotti has successfully applied Industry 4.0 principles to RMC batching, creating a framework that allows real-time adjustments based on AGG quality.
The system functions as an early warning mechanism. By knowing aggregate geometry, surface area, and moisture properties in-line, manufacturers can make precise adjustments to water, admixtures, and powders. Improving binder performance through advances in admixtures (like microsilica or nano-calcium silicate) combined with AGG-driven adjustments can improve strength and durability while managing challenges like rheology changes.
When paired with other Industry 4.0 and AI-driven tools for dispatch, QC, and mix optimization—such as Giatec Smartmix, CiDRA Smarthatch, Marcotte Batch AI, and BCMI ProPilot—Digital Aggregate offers even greater potential. Each tool contributes incremental improvements, but together they provide smarter ways to refine economic performance and enhance product quality.
As the final shocker, Masotti considers succession planning as one of the biggest paybacks for using technologies like Digital Aggregate. Newer generations do not want to get dirty to understand the business, and many older QC experts are ready to retire. Tech tools can bridge the gap for the newer generation by allowing them to use the phone already in their hands. These digital tools become a gateway to better understanding aggregate variability and maintaining QA standards. AGG can finally get the attention it deserves.
Craig Yeack has held leadership positions with both construction materials producers and software providers. He is co-founder of BCMI Corp. (the Bulk Construction Materials Initiative), which is dedicated to reinventing the construction materials business with modern mobile and cloud-based tools. His Tech Talk column—named best column by the Construction Media Alliance in 2018—focuses on concise, actionable ideas to improve financial performance for ready-mix producers. He can be reached at Craig.Yeack@bcmicorp.com.