A reply to J. Bensted's discussion of the paper “the effect of glucose and some glucose oxidation products on the hydration of tricalcium aluminate”

✍ Scribed by N.B. Milestone

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 40 KB
• Volume: 7
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(77)90125-9

✦ Synopsis

Acceleration by sugars and related compounds has been noted previously in C3A hydration (I) and cement hydration ( 2), but at levels much lower than that suggested by Dr. Bensted. Care is usually taken to avoid the rapid temperature rise and subsequent flash set. In C~A hydration, addition of sugar acids at levels higher than I% by weight results in no hydration detectable by DTA. For C3S and cement hydration, the level of addition at which hydration ceases is 0.1% (3) and at this level no hydration products are detectable.

Breakdown of glucose, but more especially fructose, under the alkaline conditions does occur and allows hydration to proceed slowly. I have not observed jelly-like adducts in the hydration products as described by Dr. Bensted. Amorphous, mucilaginous products have been reported between sugars and tetracalcium aluminate hydrate (4). With a cement high in C3A it is possible these products could be observed if hydration is accompanied by flash setting.