Facts About Volumetric Concrete
Despite being around since the mid-1960s, and rapidly growing in use in recent years, many in the concrete industry and complementary professions don’t know a lot about volumetric concrete. Worse, there are some persistent myths or biases against volumetric concrete and its capabilities. Here we present several facts about our mixer trucks and the projects they complete with the aim of educating, while setting the record straight regarding disinformation about this approach to making and placing concrete.
No matter what size the job is, a volumetric pour saves the operator and the customer money. By mixing and delivering exactly the right amount of fresh concrete, waste is eliminated, and the customer pays only for what they need and use. With the ability to pour 10 yards of concrete, you can fire up the big batch plant at no additional cost for night or weekend jobs too.
Many people believe volumetric concrete is for smaller jobs. One big advantage to volumetric concrete is its flexibility. While volumetric mixer trucks have some distinct advantages when it comes to small jobs, they are also the most capable of handling the largest of projects.
A volumetric mixer holds enough material to produce almost twice as much concrete as a ready-mix drum truck; and for larger pours, additional raw material can be delivered to the job site, allowing the volumetric truck to be reloaded as many times as needed while handling a continuous pour. With modern mixer machines producing a yard of concrete a minute and 60 yards per hour, larger jobs may require one or more volumetric mixers, but they can handle even the biggest projects.
There are also distinct advantages of volumetric pours for larger jobs. If something interrupts or delays the pour, there’s no concrete sitting in drums that may be bad by the time the pour resumes. For jobs where a steady flow of quality concrete is needed over an extended time, like pouring curbs and gutters, concrete mixed as it is put in place over a distance will be more consistent in quality than a pour from one or more drum trucks.
For critical applications like emergency roadway repair, or any project with time constraints, volumetric concrete has many advantages. For overnight or weekend freeway repair, where the work must be complete for the road to be fully opened once weekday rush hour comes, there’s no other option for fast, quality work.
For example, if a vehicle hits a safety barrier that must be fixed ASAP, or if part of a bridge or overpass deck fails, those need to be fixed as soon as possible. A volumetric truck ready and on call 24×7, it’s available any day, time, place, or weather.
Rapid set projects have become a huge and growing market to get roads back up and running as quickly as possible, producing 4000-psi product in four hours. There’s no other way to make emergency repairs, or planned repairs under tight time constraints.
Training requirements to operate a volumetric concrete mixer may be more demanding than the requirements for drum truck drivers, given that anyone operating a volumetric mixer needs to know the intricacies of running a mobile batch plant. That learning curve can be conquered quickly thanks to evolving truck technology and manufacturer training we provide through Volumetric University, in addition to the training available from VMMB and ASTM.
Volumetric trucks are considered easier to drive than drum trucks, giving operators a broader field of candidates who can drive a volumetric mixer and can then be trained to operate it on site. That can help mitigate the industry’s ongoing driver shortage and may also attract candidates who want to do more than just drive.
Regulation & Certification
Along with the volumetric mixers manufacturers bureau (VMMB) operator training and volumetric mixer standards, the American Society for Testing and Materials (ASTM) created a Standard Specification for Concrete Made by Volumetric Batching and Continuous Mixing, ASTM C 685, in 1971. The latest version is ASTM C 685/C 685M-01. The American Concrete Institute (ACI) created the Guide for the Use of Volumetric Measuring and Continuous Mixing Concrete Equipment, ACI 304.6R-91.
Other relevant specifications include ACI 548.4-93, Standard Specification for Latex-Modified Concrete (LMC) Overlays, updated to 548.4-11; and the American Association of State Highway and Transportation Officials (AASHTO) M 241-93.
Efficiency & Environment
Volumetric mixers can be significantly more efficient and environmentally friendly than drum mixers. One volumetric truck can make one trip to the job site, where it makes precisely the amount of concrete needed, with no waste.
Research suggests that each year up to 20+ million cubic yards of ready-mix created in the U.S. returns to the plant as waste. With volumetric mixing, the customer gets exactly how much product they need, no more, no less. There’s no need to have a place to dump the excess and dispose of it properly.
Safety & Precision
Because the clock is ticking with ready-mix, the urgency to get it delivered and placed on time, and the reputation of drum mixers to be behind schedule, adds urgency to every pour that can introduce more risk on the road or at the job site.
That urgency is largely absent from a volumetric pour, as there is no pre-mixed product that may be going bad or may be rejected outright at the site. For many night projects, a volumetric mixer can do the job while eliminating the back and forth that drum mixers require. Getting to the job site and placing the product at the job site can be more relaxed when everyone knows that fresh, quality concrete is guaranteed.
Volumetric mixing brings flexibility and control to every pour. On site, that means one truck can move around and complete many small jobs. It also means that it can mix and pour multiple different types of concrete with the materials it has on board. There’s no need for additional trucks or additional trips back and forth to the plant.
Likewise, with utility projects, or any pour that requires waiting for part of the pour to set before adding more, volumetric is ideal. Some projects require multiple incremental pours over hours, and no other means is as flexible and practical.
Whether a job requires a basic concrete or a specialty mix like gunite and shotcrete, rapid-setting concrete, “flowable” fill or special grout mixes, or any combination of these, a volumetric truck is up to the task. If the concrete must be pumped into place, the volumetric mixer can produce the perfect volume of slurry needed to prime or lubricate the pump, avoiding additional charges.
With on-site mixing, delays are not as big a concern. Traffic jams or truck breakdowns are never welcome, but with ready-mix it’s not just the schedule that suffers. The likelihood quickly grows that the load becomes “hot” and can’t be used, or that water must be added on site to salvage the load, at the risk of the final product being inferior or even dangerous.
Likewise, for remote areas, pre-mixed product has a relatively brief shelf life. If the work site is far enough away, there’s simply no way to get usable concrete there unless you mix volumetrically on site.
Volumetric offers complete control over when, where, how much, and what type of concrete is mixed and applied for any type of project, big or small. That flexibility to adapt to any situation is unmatched by any other approach. It also provides the perfect solution for construction companies to add to their offerings, giving firms and their customers more flexibility, freedom, and quality; and more efficiency and revenue, boosting the bottom line.
Mixing on site and producing a flow of concrete in real time provides the opportunity to observe, test, and tweak the mix on the fly. Changing temperatures or inconsistent raw materials can introduce variables that can make the concrete off just enough that a change in the mixing proportion will produce a better product and help ensure a final project that meets or exceeds expectations.
We hope this has made you aware of the distinct advantages volumetric concrete brings to every job, big or small. Would you like to know how we can help boost your profit, become more efficient, and reduce waste? Contact us today, or schedule a meeting We look forward to hearing from you.