Page 415 - Handbook of Thermal Analysis of Construction Materials

392 Chapter 9 - Non-Portland Cement Binders and Concrete

9.0 MECHANICAL PROPERTIES AND
DURABILITY OF JET SET-BASED
CEMENT SYSTEMS

9.1 Strength, Microhardness, and Modulus of
Elasticity

Early strength development of Jet Set mortars is generally obtained
(up to 15 MPa) within six hours. The strength-time curves for mortars (Fig.
12) indicate slow strength gain between six hours and one day followed by
a second period of rapid strength development.
The formation of ettringite, and to some extent monosulfate hy-
drate, mainly contribute to strength development within the first 12 hours.
Calcium silicate hydrate formation contributes to the strength after 12
hours. It has been suggested that the low rate of strength gain from 6 to 24
hours is due to the conversion of ettringite to monosulfate, which has about
50% of the theoretical strength of ettringite. [73] Alite in Reg Set cement
hydrates much faster than monoclinic alite in portland cement.

Figure 12. Compressive and bending strength of jet cement mortar (w/c = 0.65,
sand/cement = 2, at 20°C). [73]