Ceramics-Silikáty 48, (2) 49 - 58 (2004) |
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ELECTRICAL PROPERTIES, PHYSICO-CHEMICAL AND MECHANICAL CHARACTERISTICS OF FLY ASH-LIMESTONE-FILLED POZZOLANIC CEMENT |
Heikal Mohamed 1, Helmy Ivon 2, El-Didamony Hamdy 2,
El-Raoof Fawzia Abd 2 |
1 Chemistry Department, Faculty of Science, Zagazig University, Benha Branch, Benha, Egypt
2 Faculty of Science, Zagazig University, Zagazig, Egypt
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Keywords: Fly ash, Limestone, Conductivity, Phase composition, Mechanical properties |
In this paper fly ash was replaced partially up to fully by limestone dust. The change in the electrical conductivity was reported
during setting and hardening after gauging with water. The phase composition was studied by XRD and DTA. Degree of
hydration, gel/space ratio, reaction ratio, porosity and mechanical properties as well as free lime content was studied. The
results show that the substitution of fly ash by 5-10 wt.% limestone in SRC pastes decreases the conductivity. Increase of limestone
content (15 and 20 wt.%), the electrical conductivity increases than sample free from limestone (S.0). 5 wt.% limestone
extended the final setting times. On the other side, the increase of limestone content, the final setting times are shortened, this
is due to the filling effect of the limestone. The combined water, degree of hydration and the gel/space ratio increase with
limestone content. It was shown that the free lime of S.0, S.5 as well as M.0, M.5 increase up to 7 days, and then decreases
up to 90 days. On the other hand, the compressive strength and total porosity decrease with limestone content. |
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