Quantification of structure formation in setting stuccoes influenced by additives

Summary: The additives used to control the hydration of calcium sulfate hemihydrate generally influence the morphology of the developing dihydrate crystals. These morphological modifications have a direct effect on the microstructure of the solidified product, resulting in definitive determination of its macroscopic properties. The following presents an analytical method which permits simultaneous and thus prompt quantification of the developing microstructure. The results obtained using this procedure have been confirmed by comparison with conventional test methods.

1 Introduction

The setting of stucco is controlled by means of the addition of additives. These generally cause acceleration or retardation of the rehydration of the hemihydrate to dihydrate. In many cases, such intervention in the setting process results in morphological modification of the nascent dihydrate crystals [1]. Crystal morphology, for its part, influences the macroscopic properties of the finished product. Up to now, the integral effects of the structural changes associated with the crystal morphology of stucco have been determined solely via determination of the mechanical...

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