Superplasticizers in the calcium sulfate system – plasticizing action and influence on hydration

How do superplasticizers influence the hydration of calcium sulfate? Systematic investigations were used to compare the action of polycondensate and polycarboxylate superplasticizers with that of the latest dispersion technology from BASF – a comb polymer with phosphate groups. The addition of the superplasticizers was shown to obstruct not only the nucleation but also the crystal growth.

1 Introduction

The use of superplasticizers to optimize the consistency and the amount of water required is now indispensable for numerous practical applications in the field of calcium sulfate binders. This development started with sulfonated polycondensate products based on lignin, melamine and naphthalene. After polycondensates had proved successful in numerous binder systems there followed a new generation of superplasticizers, the polycarboxylate ethers (PCEs). These are characterized by significantly greater effectiveness and long-lasting flowability. PCEs can also be adapted specifically...

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