Belite-sulfoaluminate-ferrite cement

Belite-sulfoaluminate-ferrite cement (BSAF) suhbbehte cement with a particulariy... 

In addition to polyvinyl alcohol/acetate and polyacrylamide, some other polymers have also been employed as the orgarric constituents of MDF cement, including polypropylene glycol (Hsu and Juaang, 1992) and hydroxypropyl-methyl cellulose (Drabik et al., 1992, 1998). As well as Portland and calcium aluminate cements, sulfoaluminate-ferrite-belite cement (in combination with hydroxypropyl-methyl cellulose) has also been employed as constituent of an MDF material (Drabik ei a/., 1992, 1997, 1998). 

The development of strength and the extent of expansion will depend on the composition of the cement and the proportions of the phases involved. Within reasonable limits and at appropriate calcium sulfate contents the early strength will increase with increasing amounts of the sulfoaluminate phase in the cement and— to a lesser extent— with increasing content of the ferrite phase. However, the belite phase will affect maiidy the final strength of the cement. Table 4.2 shows the effect of cement composition on the compressive strength development of a series of sulfobelite cements. 

Belite fluoro-sulfo-aluminate cement contains simultaneously the phases calcium fluoroaluminate (CjjAy.CaF2) and caldum sulfoaluminate (C4A3S), together with belite and calcium sulfate. It also may contain limited amounts of the ferrite phase. 

Figure 4.1 XRD scans (IO°-45° 20 range) of typical industrially produced cements white Portland cement (WPC), plain portland cement (PC), calcium aluminate cement (CAC) and calcium sulfoaluminate cement (CSA). The diffraction peaks of the main phases are indicated alite (CjS M3), belite (P-CjS), aluminate (CjA), ferrite (C4AF), calcium aluminate (CA), ye elimite (Yee), anhydrite (Anh), gypsum (Gyp), gehlenite (Geh), mayenite (May) and magnetite (Mag).

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