Activation of Ground Granulated Blast Furnace Slag Cement by Calcined Alunite

作者：Kim Hyung Seok; Park Joo Won; An Yong Jun; Bae Jong Soo; Han Choon^*

来源：Materials Transactions, 2011, 52(2): 210-218.

DOI：10.2320/matertrans.M2010350

• ground granulated blast furnace slag (GGBFS)
• activator
• alunite
• potassium aluminum sulfate
• ettringite

To enhance the early strength of grounded granulated blast furnace slag (GGBFS) blended cement, the activation characteristics of GGBFS were examined by a potassium aluminum sulfate (PSA) clinker, consisting of KAl(SO4)(2) and amorphous Al2O3 by calcining alunite [K2SO4 center dot Al-2(SO4)(3)center dot 4Al(OH)(3)] at 650 degrees C for 30 min. The PSA clinker reacted with calcium hydroxide and gypsum to form ettringite (3CaO center dot Al2O3 center dot 3CaSO(4)center dot 32H(2)O, AFt) by following reaction: 2KAl(SO4)(2) + 2Al(2)O(3) + 13Ca(OH)(2) + 5(CaSO4 center dot 2H(2)O) + 74H(2)O -> 3(3CaO center dot Al2O3 center dot 3CaSO(4)center dot 32H(2)O) + 2KOH. Mortar was prepared by mixing a blended cement of GGBFS and ordinary Portland cement (OPC) with PSA clinker as activator. The compressive strength of the GGBFS blended cement mortar was compared with that of OPC mortar. When the PSA clinker and gypsum activator was added to the blended cement of GGBFS and OPC, the hydration products investigated by DTA and X-ray diffraction were mainly ettringite and calcium silicate hydrate(C-S-H) gel. The early and long-term strengths of the GGBFS blended cement were higher than those of OPC. Therefore, PSA clinker as activator was shown to improve the early and long-term strengths of GGBFS blended cement. [doi:10.2320/matertrans.M2010350]

• 出版日期2011-2