You may not be an expert on all things concrete. That’s okay, because you don’t have to be. Let Shelly Co. be the expert, and you can trust us to know all there is about ready mix concrete.
Ready mix concrete is specially manufactured to be delivered to the construction site in a state that’s mixed and unhardened. This kind of concrete—popularly called RMC—is made in a batching plant or a factory under specially controlled conditions. RMC is often preferred to on-site concrete mixes because the ready mix variety can mixed using specialized equipment to get just the right mixture. It uses a set recipe and then is delivered to a work site by trucks with in-transit mixers. Specialty mixtures can be sent right where they’re needed, like a gourmet meal on wheels. Ready mix concrete is by far the most common form of concrete, accounting for nearly three-quarters of all concrete. Ready mix concrete is bought and sold by volume, usually by the cubic meter. Where on-site mixtures are used instead, it’s because the job or supply chain demands more flexibility.
So what’s in ready mix concrete? RMC is a mixture of cement, water, and aggregates. Cement, the most important element of the mix, is the ingredient that lends concrete its resistance. Water is the vital fluid of the mix. It sets off a chemical reaction when it comes in contact with the cement. Aggregates, which make up the most abundant part of the mix—roughly 60 to 70 percent of the volume—are sand, gravel, and crushed stones obtained from quarries or aggregate banks. Lastly, solid or liquid additives are introduced to ready mix concrete before or during preparation. These increase concrete’s durability or shorten its setting time.
All of these ingredients are procured individually, then mixed in specific proportions as dictated by the needs of the job. During the mixing phase, the components are brought together into a uniform concrete mass. Care is taken to precisely measure the mixing time, which begins the moment the water and other material are poured into the cement mixer and the mixer begins rotating. While it’s on the way to a site, the mixer never stops rotating, and it goes at a speed of two to six rotations per minute.
Because of its ability to be mixed precisely off-site to exact specifications by specialized equipment, ready mix concrete remains the most popular form of concrete.
For an accurate estimate of the ready mix concrete amounts needed for a project, please visit our calculators page.