Theories of expansion in sulfoaluminate - type expansive cements: Schools of thought
β Scribed by M.D. Cohen
- Book ID
- 102999948
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- English
- Weight
- 566 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0008-8846
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β¦ Synopsis
This paper discusses the theories of expansion in sulfoaluminate type expansive cements.
There are two major schools of thought: the Crystal Growth Theory and the Swelling Theory.
According to the first school, expansion is caused by the growth of ettringite crystals from the surfaces of the expansive particles or from the solution resulting in a crystallization pressure and, hence, expansive force. According to the second school, expansion is caused by water-adsorption and swelling characteristics of ettringite gel which forms by a through-solution mechanism.
Observations supporting and contradicting the two schools are briefly reviewed.
π SIMILAR VOLUMES
In tests conducted on blended Type K expansive cements, it was observed that in fine blends, the main expanding particles (C4A3~) and sulfates deplete faster compared to identical coarser blends because the fine blends have a larger number of expansive sites. This can decrease the expansion time and
The hydration and setting time of MgO-type expansive cement was investigated. The results show that the addition of MgO retards the initial hydration of the cements and increases the setting time. The causes for the retardation of hydration can be attributed to: (1) since the solubility product cons
## 531 before mentioned, the total length of the test may be altered as required. ## EXPANSION OF NEAT PORTLAND CEMENT IN STEAM.