Similar articles

Abstract: This paper deals with the hydration of a blend of portland cement and activated coal gangue in order to determine the relationship between the degree of hydration and compressive strength development. The hydration process was investigated by various means: isothermal calorimetry, thermal analysis, non-evaporable water measurement, and X-ray diffraction analysis. The results show that the activated coal gangue is a pozzolanic material that contributes to the hydration of the cement blend. The pozzolanic reaction occurs over a period of between 7 and 90 d, consuming portlandite and forming both crystal hydrates and ill-crystallized calcium silicate hydrates. These hydrates are similar to those found in pure portland cement. The results show that if activated coal gangue is substituted for cement at up to 30% (w/w), it does not significantly affect the final compressive strength of the blend. A long-term compressive strength improvement can in fact be achieved by using activated coal gangue as a supplementary cementing material. The relationship between compressive strength and degree of hydration for both pure portland cement and blended cement can be described with the same equation. However, the parameters are different since blended cement produces fewer calcium silicate hydrates than pure portland cement at the same degree of hydration.

[1]Feng, B., 2000. Study on coal–refuse activity. Shanghai Environmental Science, 19(7):349-351, 353 (in Chinese).

[2]Kakali, G., Perraki, T., Tsivilis, S., Badogiannis, E., 2001. Thermal treatment of kaolin: the effect of mineralogy on the pozzolanic activity. Appled Clay Science, 20(1-2):73-80.

[3]Li, C., Wan, J.H., Sun, H.H., Li, L.T., 2010. Investigation on the activation of coal gangue by a new compound method. Journal of Hazardous Materials, 179(1-3):515-520.

[4]Li, D.X., Song, X.Y., Gong, C.C., Pan, Z.H., 2006. Research on cementitious behavior and mechanism of pozzolanic cement with coal gangue. Cement and Concrete Research, 36(9):1752-1759.

[5]Lippmaa, E., Mägi, M., Samoson, A., Engelhardt, G., Grimmer, A.R., 1980. Structural studies of silicates by solid-state high-resolution ²⁹Si NMR. Journal of the America Chemical Society, 102(15):4889-4893.

[6]Liu, X.P., Wang, P.M., 2008. Interface structure of Portland coal gangue blended cement. Journal of the Chinese Ceramic Society, 36(1):104-111 (in Chinese).

[7]Palomo, A., Blanco-Varela, M.T., Granizo, M.L., Puertas, F., Vazquez, T., Grutzeck, M.W., 1999. Chemical stability of cementitious materials based on metakaolin. Cement and Concrete Research, 29(7):997-1004.

[8]Rojas, M.F., Sánchez de Rojas, M.I., 2005. Influence of metastable hydrated phases on the pore size distribution and degree of hydration of MK-blended cements cured at 60 °C. Cement and Concrete Research, 35(7):1292-1298.

[9]Shigemoto, N., Sugiyama, S., Hayashi, H., Miyaura, K., 1995. Characterization of Na-X, Na-A, and coal fly ash zeolites and their amorphous precursors by IR, MAS NMR and XPS. Journal of Materials Science, 30(22):5777-5783.

[10]Shvarzman, A., Kovler, K., Grader, G.S., Shter, G.E., 2003. The effect of dehydroxylation/amorphization degree on pozzolanic activity of kaolinite. Cement and Concrete Research, 33(3):405-416.

[11]Singh, P.S., Trigg, M., Burgar, I., Bastow, T., 2005. Geopolymer formation processes at room temperature studied by ²⁹Si and ²⁷Al MAS-NMR. Material Science and Engeneering A, 396(1-2):392-402.

[12]Wang, P.M., Liu, X.P., 2011. Effect of temperature on the hydration process and strength development in blends of Portland cement and activated coal gangue or fly ash. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 12(2):162-170.

[13]Wang, P.M., Liu, X.P., Hu, S.G., Nü, L.N., Ma, B.G., 2007. Hydration models of Portland coal gangue cement and Portland fly ash cement. Journal of the Chinese Ceramic Society, 35(S1):180-186 (in Chinese).

[14]Wei, Q.W., Gao, W.Y., Sui, X.G., 2010. Synthesis of low-temperature, fast, single-firing body for porcelain stoneware tiles with coal gangue. Waste Management and Research, 28(10):944-950.

[15]Xie, X.W., 2009. Comprehensive utilization of coal gangue. Shanghai Environmental Science, 22(S1):121-123 (in Chinese).

[16]Zhang, J.X., Sun, H.H., Sun, Y.M., Zhang, N., 2010. Corrosion behavior of steel rebar in coal gangue-based mortars. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 11(5):382-388.

[17]Zibouche, F., Kerdjoudj, H., Lacaillerie, J.B.d.d., Damme, H.V., 2009. Geopolymers from Algerian metakaolin. Influence of secondary minerals. Applied Clay Science, 43(3-4):453-458.