Verifi can automatically add water-reducing admixtures to concrete in the truck to maintain slump.
Choosing the right types of water reducing admixtures is important. A wide array of water-reducers is commercially available and can be categorized as follows.
ASTM C494, the standard specification for chemical admixtures for concrete, defines water reducers based on the amount of water reduction and corresponding effects on setting time, compressive strength, flexural strength, shrinkage, and freeze-thaw durability.
Water Reducing Admixture: water reduction of 5% or greater
Mid-Range : Although not defined in ASTM C494, most chemical admixture companies market this category
High-Range: water reduction of 12% or greater
The terms superplasticizer and high-range water reducing admixture (HRWRA) can be used interchangeably.
The most common types of chemistry used in water reducers include:
Sugars/Sugar Acids, such as molasses, corn syrup, and gluconate
Melamine Sulfonate Formaldehyde Condensate (MSFC)
Naphthalene Sulfonate Formaldehyde Condensate (NSFC)
Polycarboxylate Ether (PCE)
Most commercially available admixtures are a formulation of multiple chemical ingredients. The above types of chemistries can be blended together or with other chemical ingredients to achieve performance characteristics such as delayed or accelerated setting time, controlled air content, increased finishability, or enhanced rheology.
Admixtures suppliers market admixtures under different brands, each representing different performance categories. Several products may be sold under each brand, each tailored to different applications.
Selecting Admixtures for Verifi
Verifi recommends the use of polycarboxylate-based superplasticizers. These are the latest generation of superplasticizers and can be engineered at the molecular level for specific performance, such as effects on setting time and early age strength.
When the correct polycarboxylate-based superplasticizer is chosen, the dose can be varied as conditions change to maintain a consistent slump at discharge, while also ensuring consistent setting time, air content, and strength development.