Concrete Mix, Water Reducers

You may be enjoying the benefits of water reducers whether you know it or not. Tony Schlagbaum, group product line manager at DeGussa Admixtures Inc. in Cleveland, estimates that 70 percent to 80 percent — maybe as high as 90 percent — of concrete mixes contain some form of water reducer. And water reducers are used for good reason — they offer many benefits.

“Water reducers do exactly what the name says: They allow concrete to be mixed with less water,” observes Bart Sacco, president of Concrete Texturing Tools & Supply in Throop, Pa. In addition, water reducers can be used to provide additional workability at the same water-to-cement ratio.

The main reason to add water to concrete — above and beyond what is needed for the proper hydration of the cement particles — is to improve workability, of course. “The rule of thumb is: 0.22 to 0.25 water-to-cement ratio is required for complete hydration,” says Schlagbaum. Most mixes have water-to-cement ratios of 0.40 to 0.60 primarily for workability purposes, he adds. But keeping the water-to-cement ratio down through the use of water reducers improves the concrete’s hardened properties.