Electrical conductivity of concrete containing silica fume: Fid-Bau Portal

Electrical conductivity of concrete containing silica fume

Abo El-Enein, S.A. / Kotkata, M.F. / Hanna, G.B. / Saad, M. / Abd El Razek, M.M.

The influence of silica fume on concrete properties represents an important technical research. In general, silica fume tends to improve both mechanical characteristics and durability of concrete. Thus the electrical properties of concrete containing silica fume can be studied to clarify its physical performance during hydration. The electrical conductivity of neat cement, mortar and concrete pastes was measured during setting and hardening. The ordinary Portland cement was partially replaced by different amounts of silica fume by weight. The changes in the electrical conductivity were reported during setting and hardening after gauging with water. The results of this study showed that the electrical conductivity can be used as an indication for the setting characteristics as well as the structural changes of the hardened pastes made with and without silica fume. The changes in electrical conductivity reflect the physical and chemical changes in the cement paste and can be used to monitor setting and hardening processes. Significant changes in electrical conductivity occur when the paste gains its rigidity. As the water/cement ratio increases, the conductivity increases and the structure growth process is retarded. The second conductivity maximum of concrete containing silica fume decreases as the silica fume ratio increases. The electrical conductivity of concrete containing silica fume, moist cured at 28 days, decreases as the silica fume content increases. The porosity of silica fume concrete moist at 28 days, decreases as the silica fume content increases up to 5 % and then increases as the silica fume content increases.