A discussion of the paper “a multi-method study of C3S hydration” by L.S. Dent-Glasser, E.E. Lachowski, K. Mohan and H.F.W. Taylor

✍ Scribed by S. Chatterji

• Publisher: Elsevier Science
• Year: 1979
• Tongue: English
• Weight: 142 KB
• Volume: 9
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(79)90133-9

✦ Synopsis

This paper has raised a number of points for discussion, however, I shall confine myself to only two. One of these is methodological and the other is conceptual.

(1) Why invent Type Ill C-S-H? To study the bulk hydration products of a paste sample by any microscopic technique it is essential to break the speci~n. The authors have used either drilling or grinding for this purpose. On a macroscale it can be shown that any polycrystalline aggregate, e.g. an aggregate of well-formed quartz crystals, on breaking will yield a mixture of irregular and morphologically regular particles. The greater the force necessary to break an aggregate the higher the proportion of irregular particles. The above is also true on the microscale (1). It is thus difficult to follow the logic of the postulation of Type Ill C-S-H (irregular particles) when it could easily have been produced by fracturing Type l C-S-H. This is like calling ground quartz a new type of SiO 2. This is doubly puzzling as the following analyses of their results show that there is no other objective basis to distinguish them.