An exploratory study on sodium sulphate-activated slag blended with Portland cement under the effect of thermal loads
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In this work, the effect of Portland cement (PC) on 1 % Na2O equivalent of sodium sulphate-activated ground granulated blast-furnace slag (hereafter referred as slag) in terms of compressive strength and pH value before and after exposure to different elevated temperatures has been investigated. Slag was partially replaced with PC at levels of 0, 5, 10 and 15 %, by mass. The specimens were exposed to different elevated temperatures ranging from 200 to 800 °C with an interval of 200 °C. The various phases formed due to elevated temperature decomposition were identified using X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. The results indicated that the inclusion of 10 and 15 % PC enhanced the compressive strength and raised the pH value. On the other hand, the neat activated slag showed the highest fire resistance. The pH value decreased with increasing elevated temperatures.
KeywordsSodium sulphate Activated slag Portland cement Elevated temperature Residual strength pH value
The author was sponsored by Egyptian government for his academic visit to Queen’s University Belfast (QUB), UK. The slag used in this research was supplied by Hanson Cement. Prof. P. A. M. Basheer, Dr. Yun Bai and the facilities provided by the School of Planning, Architecture and Civil Engineering at Queen’s University Belfast are also gratefully acknowledged.
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