Resources Recycling (자원리싸이클링)

The Korean Institute of Resources Recycling (한국자원리싸이클링학회)
권호 표지
DOI QR코드

DOI QR Code

Influence of Sulfate on Thermodynamic Modeling of Hydration of Alkali Activated Slag

알칼리 활성 슬래그의 열역학적 수화모델링에 대한 황산염의 영향

  • Lee, Hyo Kyoung (School of Architecture, Chosun University) ;
  • Park, Sol-Moi (Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology) ;
  • Kim, Hyeong-Ki (School of Architecture, Chosun University)
  • 이효경 (조선대학교 건축학부(건축공학전공)) ;
  • 박솔뫼 (KAIST 건설 및 환경공학과) ;
  • 김형기 (조선대학교 건축학부(건축공학전공))
  • Received : 2018.10.23
  • Accepted : 2019.02.01
  • Published : 2019.02.28
Download PDF
⟨ Previous Next ⟩

Abstract

The present study investigated hydration of alkali activated slag incorporating sulfate as a form of anhydrite by employing thermodynamic modeling using the Gibbs free energy minimization approach. Various parameters were evaluated in the thermodynamic calculations, such as presence of sulfide, precipitation/dissolution of AFt/AFm phase, and the effect of oxic condition on the predicted reaction. The calculations suggested no significant difference in the void volume and chemical shrinkage, which might influence the performance of the mixtures, in spite of various changes of the parameters. Although the types of hydration products and their amount varied according to the input conditions, their variations were smaller range than that induced by water-to-binder ratio. Moreover, it did not affect the amount of C-(N-)A-S-H which was the most important hydration product.

본 연구에서는 석고의 형태로 황산염이 혼입된 알칼리 활성 슬래그의 수화반응에 대해, 깁스 최소화 에너지 개념을 이용한 반응계산 결과가 계산 조건에 따라 어떻게 달라지는지에 대해 확인하였다. 계산을 위한 변수로는 황화물의 고려 여부, AFt/AFm 상의 생성가능성 여부, 대기 중 산소의 반응기여 여부 등을 검토하였다. 계산결과, 실제 위의 다양한 조건의 변화에도 불구하고 공극량, 화학수축과 같이 이후 배합의 성능에 영향을 미칠 수 있을 만한 값 들은 크게 차이가 발생하지 않았는데, 이 변수들에 의한 변화폭은 물결합재비에 의한 변화폭에 비해 월등히 작은 값이었다. 생성되는 물질들의 종류 및 양은 일부 초기조건 설정에 따라 변화할 수 있으나, 가장 주요한 수화물인 C-(N-)A-S-H의 생성량에는 별다른 영향을 미치지 않았다.

Keywords

RSOCB3_2019_v28n1_32_f0001.png 이미지

Fig. 1. Phase transfers of sodium silicate-activated slag by degree of reaction (DoR).

Table 1. Chemical composition of slag (wt.%)10)

RSOCB3_2019_v28n1_32_t0001.png 이미지

Table 2. Input conditions and thermodynamic calculation results for sodium silicate-activated slag

RSOCB3_2019_v28n1_32_t0002.png 이미지

References

  1. Lothenbach, B., Scrivener, K., and Hooton, R. D., 2011 : Supplementary cementitious materials. Cement and Concrete Research, 41(12), pp.1244-1256. https://doi.org/10.1016/j.cemconres.2010.12.001
  2. Li, C., Sun, H., and Li, L., 2010 : A review: The comparison between alkali-activated slag (Si+Ca) and metakaolin (Si+Al) cements. Cement and Concrete Research, 40(9), pp.1341-1349. https://doi.org/10.1016/j.cemconres.2010.03.020
  3. Alahrache, S., Winnefeld, F., Champenois, J. B., Hesselbarth, F., and Lothenbach, B., 2016 : Chemical activation of hybrid binders based on siliceous fly ash and Portland cement. Cement and Concrete Composites, 66, pp.10-23. https://doi.org/10.1016/j.cemconcomp.2015.11.003
  4. Wang, S. D. and Scrivener, K. L., 1995 : Hydration products of alkali activated slag cement. Cement and Concrete Research, 25(3), pp.561-571. https://doi.org/10.1016/0008-8846(95)00045-E
  5. Escalante-García, J. I., Fuentes, A. F., Gorokhovsky, A., Fraire-Luna, P. E., and Mendoza-Suarez, G., 2003 : hydration products and reactivity of blast-furnace slag activated by various alkalis. Journal of the American Ceramic Society, 86(12), pp.2148-2153. https://doi.org/10.1111/j.1151-2916.2003.tb03623.x
  6. Matschei, T., Lothenbach, B., and Glasser, F. P., 2007 : The AFm phase in Portland cement. Cement and Concrete Research, 37(2), pp.118-130. https://doi.org/10.1016/j.cemconres.2006.10.010
  7. Lothenbach, B., and Gruskovnjak, A., 2007 : Hydration of alkali-activated slag: thermodynamic modelling. Advances in Cement Research, 19(2), pp.81-92. https://doi.org/10.1680/adcr.2007.19.2.81
  8. Chen, W. and Brouwers, H. J. H., 2007 : The hydration of slag, part 1: reaction models for alkali-activated slag. Journal of Materials Science, 42(2), pp.428-443. https://doi.org/10.1007/s10853-006-0873-2
  9. Myers, R. J., Lothenbach, B., Bernal, S. A., and Provis, J. L., 2015 : Thermodynamic modelling of alkali-activated slag cements. Applied Geochemistry, 61, pp.233-247. https://doi.org/10.1016/j.apgeochem.2015.06.006
  10. Myers, R. J., Bernal, S. A., and Provis, J. L., 2017 : Phase diagrams for alkali-activated slag binders. Cement and Concrete Research, 95, pp.30-38. https://doi.org/10.1016/j.cemconres.2017.02.006
  11. Lee, H. K., Song, K. I., Song, J., and Kim, H. K., 2018 : Influence of drying methods on measurement of hydration degree of hydraulic inorganic materials: 2) alkali-activated slag. Journal of the Korean Institute of Resources Recycling, 27(1), pp.106-117. https://doi.org/10.7844/KIRR.2018.27.1.106
  12. Kulik, D. A., Wagner, T., Dmytrieva, S. V., Kosakowski, G., Hingerl, F. F., Chudnenko, K. V., and Berner, U. 2013 : GEM-Selektor geochemical modeling package: revised algorithm and GEMS3K numerical kernel for coupled simulation codes. Computational Geosciences 17, pp.1-24. https://doi.org/10.1007/s10596-012-9310-6
  13. Wagner, T., Kulik, D. A., Hingerl, F. F., and Dmytrieva, S. V., 2012 : GEM-Selektor geochemical modeling package: TSolMod library and data interface for multicomponent phase models. Canadian Mineralogist 50, pp.1173-1195. https://doi.org/10.3749/canmin.50.5.1173
  14. Lothenbach, B., Kulik, D. A., Matschei, T., Balonis, M., Baquerizo, L., Dilnesa, B., and Myers, R. J., 2018 : Cemdata18: A chemical thermodynamic database for hydrated Portland cements and alkali-activated materials. Cement and Concrete Research. In Press.
  15. Helgeson, H. C., Kirkham, D. H., and Flowers, G. C., 1981 : Theoretical prediction of the thermodynamic behavior of aqueous electrolytes at high pressures and temperatures: IV. Calculation of activity coefficients, osmotic coefficients, and apparent molal and standard and relative partial molal properties to 600C and 5 kb. American Journal of Science. 281, pp.1249-1516. https://doi.org/10.2475/ajs.281.10.1249
  16. Myers, R. J., Bernal, S. A., and Provis, J. L., 2014 : A thermodynamic model for C-(N-)ASH gel: CNASH_ss. Derivation and validation. Cement and Concrete Research. 66, pp.27-47. https://doi.org/10.1016/j.cemconres.2014.07.005
  17. Ren, Q., Zhang, Y., Long, Y., Zou, Z., and Pei, J., 2018 : Crystallisation behaviour of blast furnace slag modified by adding fly ash. Ceramics International, 44(10), pp.11628-11634. https://doi.org/10.1016/j.ceramint.2018.03.237
  18. Palacios, M. and Puertas, F., 2007 : Effect of shrinkagereducing admixtures on the properties of alkali-activated slag mortars and pastes. Cement and concrete research, 37(5), pp.691-702. https://doi.org/10.1016/j.cemconres.2006.11.021
  19. Schwab, A. P., Hickey, J., Hunter, J., and Banks, M. K., 2006 : Characteristics of blast furnace slag leachate produced under reduced and oxidized conditions. Journal of Environmental Science and Health Part A, 41(3), pp.381-395. https://doi.org/10.1080/10934520500423527