Statistical Analysis of the Physical Properties in a Slag-OPC-Gypsum System as a Compound Mixing Ratio

  • You, Kwang-Suk (Minerals & Materials Processing Division, Korea Institute of Geoscience & Mineral Resources) ;
  • Lee, Kyung-Hoon (Environment & Energy Department POSCO) ;
  • Han, Gi-Chun (Minerals & Materials Processing Division, Korea Institute of Geoscience & Mineral Resources) ;
  • Kim, Hwan (Materials Science and Engineering, Seoul National University) ;
  • Ahn, Ji-Whan (Minerals & Materials Processing Division, Korea Institute of Geoscience & Mineral Resources)
  • Published : 2007.09.30


The effect of the mixing ratio of compounds in a slag-OPC-Gypsum system on the physical properties of Slag cement is investigated in this study. $Na_2SO_4$ was used as an alkali activator. Blast furnace slag cement was prepared from a mixture of blast furnace slag, ordinary Portland cement and anhydride gypsum. The fluidity and the compressive strength according to the ratio of each mixture were analyzed in statistical analyses in order to discover the parameters influencing the fluidity and compressive strength. The results showed that the hydration of blast furnace slag took place with the addition of $Na_2SO_4$ and that column-crystalline ettringite was created as the main hydration product of the blast furnace slag. In addition, it was found that the compressive strength of blast furnace slag cement tends to increase when the ordinary Portland cement content is higher up to three days. However, it is known that the compressive strength tends to increase as the blast furnace slag content becomes higher with increases in the level of OPC after 28 days. As a result of this analysis, it is believed that the ordinary Portland cement content influences the initial compressive strength of blast furnace slag cement, and that in later days this is highly influenced by the slag content.


Blast furnace slag;Activator;Hydration Activity;Ettringite;Ordinary Portland cement


  1. D. M. Roy and G. M. Idorn, 'Development of Structure and Properties of Blast Furnace Slag Cements,' J. Amer. Concr. Inst., 97 444-57 (1982)
  2. K. Isozaki, 'Some Properties of Alkali-Activated Slag Cements,' CAJ Rev., 120-23 (1986)
  3. A. R. Brough and A. Atkinson, 'Sodium Silicate-Based, Alkali-Activated Slag Mortars: Part I: Strength, Hydration and Microstructure,' Cem. Concr. Res., 32 [6] 865-79 (2002)
  4. J.-W. Ahn, H.-S. Kim, J.-S. Cho, G.-C. Han, and K.-S. Han, 'Activation Property of Blast Furnace Slag by Alkaline Activator(in Korean)' J. Kor. Ceram. Soc., 40 [10] 1005-14 (2003)
  5. J.-W. Ahn, J.-S. Cho, K.-S. You, S.-M. Cheon, K.-S. Han, G.-C. Han, and W. Kim, 'A Study of Early Strength Enhancement by Alkali Activator and Fineness Blast Furnace Slag.' The 7th International Symposium on East Asian Resources Recycling Technology., 363-67 (2003)
  6. S. D. Wang and K. L. Scrivener, 'Hydration Products of Alkali Activated Slag Cement,' Cem. Concr. Res., 25 [3] 561-71 (1995)
  7. C. Shi and R. L. Day, 'A Calorimetric Study of Early Hydration of Alkali-Slag Cements,' Cem. Concr. Res., 25 [6] 1333-46(1995)