Geo-polymerized cementitious material as a stabilizer of waste fly ash to produce green building bricks

Abstract

Fly ash (FA) and granulated blast furnace slag (GBFS) are waste materials that are readily available. The purpose of this study was to develop a cementitious material (CM) through geopolymerization and utilize it with GBFS to stabilized FA to produce sustainable building material. The strength development of CM stabilized FA was studied over the curing periods of 3, 7, 14, 28, 56 and 90 days. The specimens were evaluated for elemental composition, mineralogy, micrography and unconfined compressive strength (UCS). Stabilization of FA with GBFS yielded the highest strength of 0.24 MPa. The CM improved the strength of the specimen significantly and the strength of 8.86 MPa was attained with a mix design containing 50% FA and 50% CM. Curing for longer period up to 90 days improved the strength of the specimen to 16.03 MPa. CM proved to be the best stabilizer for the FA investigated. Stabilization of FA with a CM was successful and based on the strength attained, the specimen produced can be used to make building bricks.

Keywords

• Fly ash
• geopolymer
• slag
• sustainable building material
• stabilization
• waste beneficiation

References

1. 1. Matjie, R., Bunt, J., & van Heerden, J. (2005). Extraction of alumina from coal fly ash generated from a selected low rank bituminous South African coal. Minerals Engineering, 18(3), 299–310. https://doi.org/10.1016/j.mineng.2004.06.013
2. 2. Kr. Pati, P., & Kr. Sahu, S. (2020). Innovative utilization of fly ash in concrete tiles for sustainable construction. Materials Today: Proceedings, 33, 5301–5305. https://doi.org/10.1016/j.matpr.2020.02.971
3. 3. Reynolds-Clausen, K., & Singh, N. (2017, May). South Africa’s power producer’s revised coal ash strategy and implementation progress. In Proceedings of the World of Coal Ash (WOCA) Conference (pp. 9-11).
4. 4. Singh, N., Kumar, M., & Rai, S. (2020). Geopolymer cement and concrete: Properties. Materials Today: Proceedings, 29, 743–748. https://doi.org/10.1016/j.matpr.2020.04.513
5. 5. Tchadjie, L. N., & Ekolu, S. O. (2017). Enhancing the reactivity of aluminosilicate materials toward geopolymer synthesis. Journal of Materials Science, 53(7), 4709–4733. https://doi.org/10.1007/s10853-017-1907-7
6. 6. Samantasinghar, S., & Singh, S. P. (2018). Effect of synthesis parameters on compressive strength of fly ash-slag blended geopolymer. Construction and Building Materials, 170, 225–234. https://doi.org/10.1016/j.conbuildmat.2018.03.026
7. 7. Davidovits, J. (1991). Geopolymers. Journal of Thermal Analysis, 37(8), 1633–1656. https://doi.org/10.1007/bf01912193
8. 8. Ozer, I., & Soyer-Uzun, S. (2015). Relations between the structural characteristics and compressive strength in metakaolin based geopolymers with different molar Si/Al ratios. Ceramics International, 41(8), 10192–10198. https://doi.org/10.1016/j.ceramint.2015.04.125

9. 9. Cheng, H., Lin, K. L., Cui, R., Hwang, C. L., Cheng, T. W., & Chang, Y. M. (2015). Effect of solid-to-liquid ratios on the properties of waste catalyst–metakaolin based geopolymers. Construction and Building Materials, 88, 74–83. https://doi.org/10.1016/j.conbuildmat.2015.01.005
10. 10. Ismail, I., Bernal, S. A., Provis, J. L., San Nicolas, R., Brice, D. G., Kilcullen, A. R., Hamdan, S., & van Deventer, J. S. (2013). Influence of fly ash on the water and chloride permeability of alkali-activated slag mortars and concretes. Construction and Building Materials, 48, 1187–1201. https://doi.org/10.1016/j.conbuildmat.2013.07.106
11. 11. Wongpa, J., Kiattikomol, K., Jaturapitakkul, C., & Chindaprasirt, P. (2010). Compressive strength, modulus of elasticity, and water permeability of inorganic polymer concrete. Materials & Design, 31(10), 4748–4754. https://doi.org/10.1016/j.matdes.2010.05.012
12. 12. Ma, Y., & Ye, G. (2015). The shrinkage of alkali activated fly ash. Cement and Concrete Research, 68, 75–82. https://doi.org/10.1016/j.cemconres.2014.10.024 13. Lee, N., Jang, J., & Lee, H. (2014). Shrinkage characteristics of alkali-activated fly ash/slag paste and mortar at early ages. Cement and Concrete Composites, 53, 239–248. https://doi.org/10.1016/j.cemconcomp.2014.07.007
13. 14. Bernal, S. A., Rodríguez, E. D., Mejía de Gutiérrez, R., & Provis, J. L. (2012). Performance of alkali-activated slag mortars exposed to acids. Journal of Sustainable Cement-Based Materials, 1(3), 138–151. https://doi.org/10.1080/21650373.2012.747235
14. 15. Lloyd, R. R., Provis, J. L., & van Deventer, J. S. J. (2011). Acid resistance of inorganic polymer binders. 1. Corrosion rate. Materials and Structures, 45(1–2), 1–14. https://doi.org/10.1617/s11527-011-9744-7
15. 16. Komnitsas, K., & Zaharaki, D. (2007). Geopolymerisation: A review and prospects for the minerals industry. Minerals Engineering, 20(14), 1261–1277. https://doi.org/10.1016/j.mineng.2007.07.011
16. 17. Yadollahi, M. M., Benli, A., & Demirboğa, R. (2015). The effects of silica modulus and aging on compressive strength of pumice-based geopolymer composites. Construction and Building Materials, 94, 767–774. https://doi.org/10.1016/j.conbuildmat.2015.07.052
17. 18. Sithole, N. T., & Mashifana, T. (2020). Geosynthesis of building and construction materials through alkaline activation of granulated blast furnace slag. Construction and Building Materials, 264, 120712. https://doi.org/10.1016/j.conbuildmat.2020.120712
18. 19. Mashifana, T., Ntuli, F., & Okonta, F. (2019). Leaching kinetics on the removal of phosphorus from waste phosphogypsum by application of shrinking core model. South African Journal of Chemical Engineering, 27, 1–6. https://doi.org/10.1016/j.sajce.2018.11.001 20. Phair, J. W. (2006). Green chemistry for sustainable cement production and use. Green Chemistry, 8(9), 763. https://doi.org/10.1039/b603997a
19. 21. Chatterjee AK (2018) Cement production technology: principles and practice. CRC Press.
20. 22. SANS (2007) Burnt clay masonry units. South African National Standards (SANS 227).
21. 23. TRH 14 (1985) Guidelines for Road Construction Materials. In Pretoria, South Africa: Committee of State Road Authorities 1–57.
22. 24. Naganathan, S., Mohamed, A. Y. O., & Mustapha, K. N. (2015). Performance of bricks made using fly ash and bottom ash. Construction and Building Materials, 96, 576–580. https://doi.org/10.1016/j.conbuildmat.2015.08.068
23. 25. Brykov, A.S., Danilov, V.V., Korneev, V.I., Larichkov, A.V. (2002). Effect of Hydrated Sodium Silicates on Cement Paste Hardening. Russian Journal of Applied Chemistry 75, 1577–1579. https://doi.org/10.1023/A:1022251028590
24. 26. ASTM, C. (2010). Standard specification for building brick (solid masonry units made from clay or shale) (ASTM C62-10). West Conshohocken, PA, 19428-2959.
25. 27. ASTM, C. (2010). Standard specification for building brick (solid masonry units made from clay or shale) (ASTM C270-10). West Conshohocken, PA, 19428-2959.