Response surface optimization of geopolymer mix parameters in terms of key engineering properties


  • Şevin Ekmen Department of Civil Engineering, Harran University, Şanlıurfa (Türkiye)
  • Kasım Mermerdaş Department of Civil Engineering, Harran University, Şanlıurfa (Türkiye)
  • Zeynep Alğın Department of Civil Engineering, Harran University, Şanlıurfa (Türkiye)
  • Yusuf Işıker Department of Mechanical Engineering, Harran University, Şanlıurfa (Türkiye)



Geopolymer, water absorption, drying shrinkage, thermal conductivity, optimization.


The main aim of the current study is to search the impact of variable matrix phase features on fly ash based lightweight geopolymer mortars (LWGM). Another scope of the study is to obtain performance oriented optimum mixture proportions through response surface method (RSM). In order to have low unit weight for LWGMs, pumice aggregate was utilized as a part of the aggregate. The investigated engineering properties are water absorption, drying shrinkage and thermal conductivity. By performing optimization analysis, it was aimed to obtain the best numerical models representing the experimental results depending on the input variables. The decrease of liquid (alkali activators) to powder (fly ash) ratio, Na2SiO3 solution to NaOH solution ratio and increase of sodium hydroxide molarity led to improvement of compressive strength. Dry thermal conductivity values in dry state were observed to be less than those of saturated ones. Moreover, the higher sodium hydroxide molarity and lower Na2SiO3 solution to NaOH solution ratios, and liquid to powder ratios resulted in further shrinkage reduction. Depending on the goals of maximum compressive strength, minimum water absorption, and drying shrinkage, optimum values for molarity, SS/SH, and l/p factors were determined as 14 M, 1.586, and 0.45, respectively.


Akcay, C., & Manisali, E. (2018). Fuzzy decision support model for the selection of contractor in construction works. Revista de la Construcción. Journal of Construction, 17(2), 258-266.

American Society for Testing and Materials. (1997). ASTM C 618 : Standard specification for coal fly ash and raw or calcined natural pozzolan for use as a mineral admixture in concrete. Annual Book of ASTM Standards.

American Society of Testing and Materials. (2006). ASTM C642 Standard test method for density, absorption, and voids in hardened concrete. ASTM International, (3).

Amran, Y. H. M., Alyousef, R., Alabduljabbar, H., & El-Zeadani, M. (2020). Clean production and properties of geopolymer concrete; A review. Journal of Cleaner Production. doi:10.1016/j.jclepro.2019.119679

ASTM C109/C109M-02. (2005). Standard test method for compressive strength of hydraulic cement mortars. Annual Book of ASTM Standards.

ASTM C1437-01 (2001) Standard test method for flow of hydraulic cement mortars, Annual Book of ASTM Standards, Philadelphia, 04.01.2005, pp. 611–612.

ASTM C596–01. (2001). Standard test method for drying shrinkage of mortar containing hydraulic cement. Annual Book of ASTM Standards, 2(4).

ASTM:C33-03. (2003). Standard specification for concrete aggregates. ASTM International.

Aydin, S., & Baradan, B. (2014). Effect of activator type and content on properties of alkali-activated slag mortars. Composites Part B: Engineering, 57. doi:10.1016/j.compositesb.2013.10.001

Dai, J., Wang, Q., Bi, R., Wang, C., Han, Z., Du, W., & Chen, Z. (2022). Research on influencing factors and time-varying model of thermal conductivity of concrete at early age. Construction and Building Materials, 315, 125638. doi: 10.1016/j.conbuildmat.2021.125638

Duran Atiş, C., Bilim, C., Çelik, Ö., & Karahan, O. (2009). Influence of activator on the strength and drying shrinkage of alkali-activated slag mortar. Construction and Building Materials, 23(1). doi:10.1016/j.conbuildmat.2007.10.011

Duxson, P., Fernández-Jiménez, A., Provis, J. L., Lukey, G. C., Palomo, A., & van Deventer, J. S. J. (2007). Geopolymer technology: The current state of the art. Journal of Materials Science, 42(9). doi:10.1007/s10853-006-0637-z

Ekmen, A. B., Algin, H. M., & Özen, M. (2020). Strength and stiffness optimisation of fly ash-admixed DCM columns constructed in clayey silty sand. Transportation Geotechnics, 24. doi:10.1016/j.trgeo.2020.100364

Ekmen, Ş., Mermerdaş, K., & Algın, Z. (2021). Effect of oxide composition and ingredient proportions on the rheological and mechanical properties of geopolymer mortar incorporating pumice aggregate. Journal of Building Engineering, 34, 101893.

Hao, L., Xiao, J., Sun, J., Xia, B., & Cao, W. (2022). Thermal conductivity of 3D printed concrete with recycled fine aggregate composite phase change materials. Journal of Cleaner Production, 364, 132598. doi: 10.1016/j.jclepro.2022.132598

İşıker, Y. (2018). Development of an experimental method for determination of thermal performances of energy efficient alternative building materials. PhD Thesis, Harran University, Sanlıurfa.

Hardjito, D., Wallah, S. E., Sumajouw, D. M. J., & Rangan, B. V. (2004). On the development of fly ash-based geopolymer concrete. ACI Materials Journal, 101(6). doi:10.14359/13485

Huntzinger, D. N., & Eatmon, T. D. (2009). A life-cycle assessment of Portland cement manufacturing: comparing the traditional process with alternative technologies. Journal of Cleaner Production, 17(7). doi:10.1016/j.jclepro.2008.04.007

Jiao, Z., Wang, Y., Zheng, W., & Huang, W. (2018). Effect of dosage of sodium carbonate on the strength and drying shrinkage of sodium hydroxide based alkali-activated slag paste. Construction and Building Materials, 179. doi:10.1016/j.conbuildmat.2018.05.194

Kaya, M., & Köksal, F. (2021). Influences of high temperature on mechanical properties of fly ash based geopolymer mortars reinforced with PVA fiber. Revista de La Construcción, 20(2). doi:10.7764/RDLC.20.2.393

Li, C., Gong, X., Cui, S., Wang, Z., Zheng, Y., & Chi, B. (2011). CO2 emissions due to cement manufacture. In Materials Science Forum (Vol. 685). doi:10.4028/

Meyer, C. (2009). The greening of the concrete industry. Cement and Concrete Composites, 31(8). doi:10.1016/j.cemconcomp.2008.12.010

Mouli, M., & Khelafi, H. (2008). Performance characteristics of lightweight aggregate concrete containing natural pozzolan. Building and Environment, 43(1). doi:10.1016/j.buildenv.2006.11.038

Özen, M., Demircan, G., Kisa, M., Acikgoz, A., Ceyhan, G., & Işıker, Y. (2022). Thermal properties of surface-modified nano-Al2O3/kevlar fiber/epoxy composites. Materials Chemistry and Physics, 278, 125689. doi: 10.1016/j.matchemphys.2021.125689

Peng, J., Huang, L., Zhao, Y., Chen, P., Zeng, L., & Zheng, W. (2013). Modeling of carbon dioxide measurement on cement plants. In Advanced Materials Research (Vol. 610–613). doi:10.4028/

Razak, R. A., Abdullah, M. M. A. B., Hussin, K., Ismail, K. N., Hardjito, D., & Yahya, Z. (2015). Optimization of NaOH molarity, LUSI mud/alkaline activator, and Na2SiO3/NaOH ratio to produce lightweight aggregate-based geopolymer. International Journal of Molecular Sciences, 16(5). doi:10.3390/ijms160511629

Sarmin, S. N. (2015). Lightweight building materials of geopolymer reinforced wood particles aggregate – A Review. Applied Mechanics and Materials, 802. doi:10.4028/

Shi, J., Liu, B., Liu, Y., Wang, E., He, Z., Xu, H., & Ren, X. (2020). Preparation and characterization of lightweight aggregate foamed geopolymer con-cretes aerated using hydrogen peroxide. Construction and Building Materials, 256. doi:10.1016/j.conbuildmat.2020.119442

Wongsa, A., Sata, V., Nuaklong, P., & Chindaprasirt, P. (2018). Use of crushed clay brick and pumice aggregates in lightweight geopolymer concrete. Construction and Building Materials, 188, 1025-1034.

Zhang, P., Zheng, Y., Wang, K., & Zhang, J. (2018). A review on properties of fresh and hardened geopolymer mortar. Composites Part B: Engineering. doi:10.1016/j.compositesb.2018.06.031

Zheng, Q., Kaur, S., Dames, C., & Prasher, R. S. (2020). Analysis and improvement of the hot disk transient plane source method for low thermal conduc-tivity materials. International Journal of Heat and Mass Transfer, 151, 119331. doi: 10.1016/j.ijheatmasstransfer.2020.119331




How to Cite

Ekmen, Şevin, Mermerdaş, K., Alğın, Z., & Işıker, Y. (2022). Response surface optimization of geopolymer mix parameters in terms of key engineering properties. Revista De La Construcción. Journal of Construction, 21(3), 631–644.