A volumetric concrete mixer (also known as volumetric mobile mixer) is a concrete mixer mounted on a truck or trailer that contains separate compartments for sand, stone, cement and water. On arrival at the job site, the machine mixes the materials to produce the exact amount of concrete needed. How It Works Volumetric mixers batch, measure, mix and dispense all from one unit. Volumetric concrete mixers can produce exactly the amount of concrete needed when it is needed at any time. Some concrete suppliers offer general purpose concrete batched in a volumetric mixer as a practical alternative to ready-mix if quantities and scheduling are not fully known, in order to eliminate waste and prevent premature stiffening of the mix. The volumetric mixer varies in capacity size up to 12 m3 and has a production rate around 60m3 an hour depending on the mix design. Many volumetric concrete mixer manufacturers have innovated the mixer in capacity and design, as well as added features including color, multiple admixes, fiber systems, and the ability to do gunite or shotcrete. The advantages of a volumetric mixer include: Reduces waste and associated costs by providing exact quantities. No risk of premature stiffening of concrete if delays are encountered. Permits delivery of smaller quantities of concrete. Night time works do not require the re-opening of a concrete batch plant. Flexibility to alternate between multiple concrete mixes as required for the application. Ability to do continuous concrete pours Sustainability Less waste - exact amount of concrete is poured Less water - volumetric concrete mixers use on average 8-10 gallons of water to clean out versus 200 gallons for a traditional barrel truck Less emissions - the truck does not need to idle while waiting to pour concrete History In the mid-1960's, companies such as Cemen Tech, Reimer Mixers (manufactured under the name ProAll circa 2016), and Zimmerman began building their own versions of volumetric concrete mixers . In 1999, equipment manufacturers created a trade association, Volumetric Mixer Manufacturers Bureau (VMMB). It had six charter members: Cemen Tech, Inc., Zimmerman Ind, Inc., ProAll Reimer, Bay-Lynx, Custom-Crete, and Elkin. References External links National Ready Mixed Concrete Association Bureaus Engineering vehicles