Influences of Water Glass Parameters on Working Performance and Mechanical Properties of Alkali-Excited Geopolymers

doi:10.16552/j.cnki.issn1001-1625.2026.0190

Abstract

Abstract:

To investigate the influences of alkali activator parameters on the working performance and mechanical properties of geopolymers， the geopolymers were prepared using iron tailings sand， coal gangue powder， and blast furnace slag as raw materials， employing both solid water glass and liquid water glass as alkali activators. The effects of water glass types， modulus and Na₂O dosage on geopolymers setting time， flowability， compressive strength and flexural strength were analyzed. Additionally， SEM and XRD were conducted to reveal the strength development mechanism of water glass-excited geopolymers. The results indicate that as modulus of water glass increases， the setting time of both alkali-excited geopolymers extends. Liquid water glass-excited geopolymers exhibit a trend of initially increasing then decreasing flowability， compressive strength and flexural strength， with an optimum modulus of 1.6. Solid water glass-excited geopolymers show a decreasing trend in flowability， while compressive strength and flexural strength initially decreases then increases， with an optimum modulus of 0.6. As the Na₂O dosage increases， the setting time and flowability of the geopolymers decrease while both compressive and flexural strength increase. The geopolymers exhibits optimal performance when the Na₂O content is 6% （mass fraction）. Liquid water glass-excited geopolymers exhibit superior working performance and mechanical properties compared to solid water glass-excited geopolymers. Both solid and liquid water glass are employed to modulate geopolymer strength development by influencing the geopolymerization reaction kinetics. Notably， solid water glass exhibits a relatively low dissolution rate in the alkaline activation medium， resulting in heterogeneous distribution of reaction products and consequently impeding uniform strength gain.

Key words: alkali-excited geopolymer, water glass parameter, setting time, flowability, mechanical property, reaction mechanism

CLC Number:

TQ177

ZHOU Huiyong, WANG Yanchao, GAO Hua, GUO Wei, FAN Taotao, SI Chundi, MA Xibao. Influences of Water Glass Parameters on Working Performance and Mechanical Properties of Alkali-Excited Geopolymers[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2026, 45(9): 3163-3173.

Figures/Tables 11

Table 1 Chemical composition and basic physical properties of raw materials

Material	Density/ （g·cm^-3）	Mass fraction/%									Activity index/%
Material	Density/ （g·cm^-3）	SiO₂	CaO	Al₂O₃	MgO	Na₂O	Fe₂O₃	K₂O	SO₃	Other	Activity index/%
Iron tailings sand	2.955	68.30	6.57	4.59	4.72	0.96	12.20	1.39	0.14	1.13	81.50
Coal gangue powder	2.430	61.50	1.55	21.00	2.55	1.52	5.55	4.40	0.22	1.71	89.28
Blast furnace slag	2.900	27.30	42.90	12.40	11.00	0.66	0.65	0.55	2.19	2.35	—

Table 2 Technical specifications for water glass

Alkali activator	SiO₂ content/%	Na₂O content/%	Solid content/%	Density/（g·cm^-3）
YS	26.98	8.53	35.51	1.35
GS	49.80	25.40	—	0.83

Fig.1 Flowchart for preparation of geopolymers mortar

Fig.2 Setting time of geopolymers under different water glass modulus conditions

Fig.3 Setting time of geopolymers under different Na2O dosages

Fig.4 Effect of modulus on flowability of geopolymers mortar

Fig.5 Effect of Na2O dosage on flowability of geopolymers mortar

Fig.6 Effect of Na2O dosage on compressive strength of geopolymers mortar

Fig.7 Effect of Na2O dosage on flexural strength of geopolymers mortar

Fig.8 XRD patterns of raw materials and geopolymers

Fig.9 Morphology of geopolymers mortar activated by different water glass at 28 d age

References 28

[1]	DAVIDOVITS J， CORDI S A. Synthesis of new high temperature geo-polymers for reinforced plastics/composites［J］. Spe Pactec， 1979， 79： 151-154.
[2]	SOUSA V， BOGAS J A， REAL S， et al. Recycled cement production energy consumption optimization［J］. Sustainable Chemistry and Pharmacy， 2023， 32： 101010. DOI URL
[3]	YANG J， YU X L， HE X Y， et al. Effect of ultrafine fly ash and water glass content on the performance of phosphorus slag-based geopolymer［J］. Materials， 2022， 15（15）： 5395. DOI URL
[4]	罗　俊，彭　晖，颜继坤. 可溶性硅酸盐对电石渣-碳酸钠-矿渣基地聚物强度改善机理研究［J］. 实验力学， 2025， 40（3）： 349-358.
	LUO J， PENG H， YAN J K. Research on the mechanism of soluble silicates for improving the strength of calcium carbide residue-sodium carbonate-slag based polymer［J］. Journal of Experimental Mechanics， 2025， 40（3）： 349-358 （in Chinese）.
[5]	何　瑞，杨泽铭，颜天佑，等. 钢渣改性高延性地聚物复合材料力学性能研究［J］. 混凝土， 2025（1）： 94-98.
	HE R， YANG Z M， YAN T Y， et al. Experimental study on mechanical properties of steel slag modified high ductility geopolymer composites［J］. Concrete， 2025（1）： 94-98 （in Chinese）.
[6]	聂少君，韩秀丽，刘　磊，等. 基于响应面法的钒钛铁尾矿基地聚物配比优化［J］. 金属矿山， 2024（9）： 275-282.
	NIE S J， HAN X L， LIU L， et al. Optimization of geopolymer ratio for vanadium-titanium iron tailings base geopolymer based on response surface methodology［J］. Metal Mine， 2024（9）： 275-282 （in Chinese）.
[7]	NATH S K. Fly ash and zinc slag blended geopolymer： immobilization of hazardous materials and development of paving blocks［J］. Journal of Hazardous Materials， 2020， 387： 121673. DOI URL
[8]	张争奇，李世泽，芮照诚，等. 碱激发制备地聚物稳定再生集料及碱激发机理研究［J］. 应用化工， 2025， 54（4）： 920-926.
	ZHANG Z Q， LI S Z， RUI Z C， et al. Preparation of geopolymer stabilized recycled aggregates by alkali excitation and study on the mechanism of alkali excitation［J］. Applied Chemical Industry， 2025， 54（4）： 920-926 （in Chinese）.
[9]	张远永，张随雨，刘远，等. 反浮选磷尾矿基地聚物的制备及其水化机制研究［J/OL］. 无机盐工业， 1-11 （ 2025-08-14）［ 2026-03-21］. .
	ZHANG Y Y， ZHANG S Y， LIU Y， et al. Preparation of reverse flotation phosphorus tailings based geopolymers and research on their hydration mechanism［J/OL］. Inorganic Chemicals Industry， 1-11 （ 2025-08-14）［ 2026-03-21］. （in Chinese）.
[10]	孙双月. 利用矿渣和粉煤灰制备地质聚合物胶凝材料的正交试验研究［J］. 中国矿业， 2019， 28（11）： 118-122.
	SUN S Y. Orthogonal experiment research on geopolymer synthesis by utilizing slag and fly ash as raw material［J］. China Mining Magazine， 2019， 28（11）： 118-122 （in Chinese）.
[11]	WANG T K， QIU X L， YANG W W， et al. Study on properties and mechanism of alkali-activated geopolymer cementitious materials of marble waste powder［J］. Developments in the Built Environment， 2023， 16： 100249. DOI URL
[12]	MOHAMMED A S S K， GÉBER R， SIMON A， et al. Comparative study of metakaolin-based geopolymer characteristics utilizing different dosages of water glass in the activator solution［J］. Results in Engineering， 2023， 20： 101469. DOI URL
[13]	徐　延，彭小芹，王淑萍，等. 水玻璃及矿渣对地聚合物凝结时间的影响［J］. 材料科学与工程学报， 2020， 38（2）： 282-285+329.
	XU Y， PENG X Q， WANG S P， et al. Influence of sodium silicate and slag on setting time of geopolymer［J］. Journal of Materials Science and Engineering， 2020， 38（2）： 282-285+329 （in Chinese）.
[14]	DONG M H， ELCHALAKANI M， KARRECH A. Development of high strength one-part geopolymer mortar using sodium metasilicate［J］. Construction and Building Materials， 2020， 236： 117611. DOI URL
[15]	SUN M， MAO X Y， GAO X J， et al. Innovative encapsulation of alkali activators in alkali-activated slag concrete： a sustainable strategy for regulating setting time and durability［J］. Construction and Building Materials， 2024， 427： 136230. DOI URL
[16]	LI M J， HUANG G D， CUI Y， et al. Improvement of mechanical properties and condensation behavior for alkali-activated materials by sodium silicate［J］. Crystals， 2022， 12（8）： 1018. DOI URL
[17]	蒋明屾，李　飞，周理安，等. 碳酸钠、氢氧化钠与水玻璃复合激发对地聚物胶凝材料性能的影响［J］. 硅酸盐通报， 2024， 43（3）： 929-937.
	JIANG M S， LI F， ZHOU L A， et al. Effects of sodium carbonate， sodium hydroxide and water glass composite activation on properties of geopolymer cementitious materials［J］. Bulletin of the Chinese Ceramic Society， 2024， 43（3）： 929-937 （in Chinese）.
[18]	DAI X D， AYDIN S， YARDIMCI M Y， et al. Early age reaction， rheological properties and pore solution chemistry of NaOH-activated slag mixtures［J］. Cement and Concrete Composites， 2022， 133： 104715. DOI URL
[19]	殷素红，管海宇，胡　捷，等. 碱激发粉煤灰-矿渣灌浆材料的流变性与流动性［J］. 华南理工大学学报（自然科学版）， 2019， 47（8）： 120-128+135.
	YIN S H， GUAN H Y， HU J， et al. Rheological properties and fluidity of alkali-activated fly ash-slag grouting material［J］. Journal of South China University of Technology （Natural Science Edition）， 2019， 47（8）： 120-128+135 （in Chinese）.
[20]	DAI X D， AYDıN S， YARDıMCı M Y， et al. Effects of activator properties and GGBFS/FA ratio on the structural build-up and rheology of AAC［J］. Cement and Concrete Research， 2020， 138： 106253. DOI URL
[21]	MOHAMED O A， NAJM O， AHMED E. Alkali-activated slag & fly ash as sustainable alternatives to OPC： sorptivity and strength development characteristics of mortar［J］. Cleaner Materials， 2023， 8： 100188. DOI URL
[22]	杨立荣，王春梅，封孝信，等. 粉煤灰/矿渣基地聚合物的制备及固化机理研究［J］. 武汉理工大学学报， 2009， 31（7）： 115-119.
	YANG L R， WANG C M， FENG X X， et al. Preparation and consolidation mechanism of fly ash-based geopolymer incorporating slag［J］. Journal of Wuhan University of Technology， 2009， 31（7）： 115-119 （in Chinese）.
[23]	章定文，王安辉. 地聚合物胶凝材料性能及工程应用研究综述［J］. 建筑科学与工程学报， 2020， 37（5）： 13-38.
	ZHANG D W， WANG A H. Review on property of geopolymer binder and its engineering application［J］. Journal of Architecture and Civil Engineering， 2020， 37（5）： 13-38 （in Chinese）.
[24]	LI J， YANG L， RAO F， et al. Influence of Ca on the mechanical properties and microstructures of slag-fly ash geopolymers［J］. Minerals and Mineral Materials， 2022， 1： 2. DOI URL
[25]	李昊杰，杨爱武，唐新科，等. 地聚物多因素协同作用下凝结与硬化特性分析［J/OL］. 湖南大学学报（自然科学版）， 1-11 （ 2025-10-22）［ 2026-03-21］. .
	LI H J， YANG A W， TANG X K， et al. Analysis of setting and hardening characteristics of geopolymers under synergistic effects of multiple factors［J/OL］. Journal of Hunan University （Natural Sciences）， 1-11 （ 2025-10-22）［ 2026-03-21］. （in Chinese）.
[26]	SAMARAKOON M H， RANJITH P G， DE SILVA V R S. Effect of soda-lime glass powder on alkali-activated binders： rheology， strength and microstructure characterization［J］. Construction and Building Materials， 2020， 241： 118013. DOI URL
[27]	PROVIS J L， BERNAL S A. Geopolymers and related alkali-activated materials［J］. Annual Review of Materials Research， 2014， 44： 299-327. DOI URL
[28]	SHI D， YE J Y， ZHANG W S. Effects of activator content on properties， mineralogy， hydration and microstructure of alkali-activated materials synthesized from calcium silicate slag and ground granulated blast furnace slag［J］. Journal of Building Engineering， 2020， 32： 101791. DOI URL