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11DBMC International Conference on Durability of Building Materials and Components ISTANBUL, Turkey 11-14 May 2008 Effect of Fire on Microstructure and Mechanical Properties of Blended Cement Pastes Containing Metakaolin and Silica Fume M. S. Morsy 1 S. S. Shebl 2 A. M. Rashad 3 T 11 ABSTRACT The influence of high temperature on microstructure and mechanical properties of cement paste is vital to characterize fire resistance. Some experimental investigations on the microstructure and compressive strength of pre-heated metakaolin-silica fume blended cement pastes are presented in this paper. The aim of this investigation is to study the effect of substitution of metakaolin (MK) by silica fume (SF) on thermal stability of Portland cement-MK blended pastes. The kaolinite was thermally activated at 850 o C for 2 hours. The cement pastes were prepared using standard water of consistency. The pastes were kept in moulds at 20 o C and 100% relative humidity for 24 hours and then hydrated for 28 days under water. The hydrated pastes were exposed for 2 hours to temperature 200, 400, 600 and 800 o C. The pre-heated specimens were tested for compressive strength, thermal stability, microstructure and phase composition. The thermal shock resistances were performed on cement pastes after hydration. The results of investigation showed that the compressive strength of pre-heated blended cement increases with temperature up to 400 o C and then, it decreases as the pre-heated temperatures increase up to 800 o C. The replacement of Portland cement, PC, by 15% MK and 15% SF in cement pastes increases the thermal shock resistance by about 20 times than control KEYWORDS Blended cement, Microstructure, Thermal Shock Resistance, Compressive Strength, DSC 1 Housing & Building National Research Center, Building Physics Department, Cairo, Egypt, Phone +20237617062, Fax +20233351564, [email protected] 2 Housing & Building National Research Center, Building Physics Department, Cairo, Egypt, Phone +20237617062, Fax +20233351564, [email protected] 3 Housing & Building National Research Center, Strength of Building Materials and Quality Control Department, Cairo, Egypt, Phone +20237617062, Fax +20233351564, [email protected]
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Effect of Fire on Microstructure and Mechanical Properties of Blended Cement Pastes Containing Metakaolin and Silica Fume

Apr 27, 2023

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