SI-29 MAS-NMR STUDY OF HYDRATED CEMENT PASTE AND MORTAR MADE WITH ANDWITHOUT SILICA FUME

This paper presents Si-29 MAS-NMR measurements that trace the hydratio n process in both cement paste and mortar specimens made from ordinary portland cement, Type I, when the cement content is replaced by 0, 10 , 15, and 20 wt% of silica fume. The specimens were moist-cured for 3, 7, 14, 28, 90, and 180 days at a laboratory temperature of 21 degrees C (69.8 degrees F). Compressive strength for all tested specimens was also determined. The results show that the degree of hydration (Q(1) + Q(2))/(Q(o) + Q(1) + Q(2)) increased with increasing content of sili ca fume, especially at the early ages of 3 to 28 days. In the same man ner, compressive strength results were markedly increased up to 14 day s and were lowered at later ages, compared to the control mix (0 wt% s ilica fume).