Open AccessArticle

Performance Investigation of Geopolymer Grouting Material with Varied Mix Proportions

Jianwei Liu

^1,2,

Han Feng

³,

Yongxing Zhang

^1,2,* and

Kaiqi Zheng

^1,2

School of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China

Key Laboratory of Concrete and Pre-Stressed Concrete Structure of Ministry of Education, Southeast University, Nanjing 210096, China

School of Civil Engineering, Central South University, Changsha 410075, China

Author to whom correspondence should be addressed.

Sustainability 2022, 14(20), 13046; https://doi.org/10.3390/su142013046

Submission received: 11 September 2022 / Revised: 8 October 2022 / Accepted: 9 October 2022 / Published: 12 October 2022

(This article belongs to the Special Issue Marine Geotechnical Engineering and Marine Civil Engineering Construction)

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Abstract

Grouting materials require not only high ultra-early-stage strength of the stone body, but also proper working performances, such as high fluidity and fast setting time, as well as good stability. Compared with the traditional pure cement grout, geopolymer grouting material has the advantages of fast setting time, high fluidity, good slurry stability, and high early strength of the slurry stone body, which is beneficial to reuse solid waste resources and can be applied to the conditions of rapid construction or repair work to a certain extent. This paper presents an experimental investigation into the performance variation of geopolymer grouting material with varied mass fractions of raw materials, and the grouting performance of geopolymer material with optimal mix proportion is also presented. The study is implemented by employing the designed experimental schemes, focused on fluidity and setting times, as well as ultra-early-stage (4 h, 8 h, 12 h, 16 h, 20 h, and 24 h) mechanical strength. The experimental result demonstrates that both ground granulated blast-furnace slag (GGBS) content and the mass ratio of activator solution to solid have influence on the working performance of geopolymers, and both GGBS content and activator concentration have influence on the mechanical strength of geopolymers. Furthermore, the variance analysis demonstrates that the fluidity of geopolymer material is dominantly affected by the mass ratio of activator solution to solid, the setting time of geopolymer material is mainly influenced by GGBS content, and the mechanical strength of geopolymer material is mainly affected by activator concentration. Moreover, the recommended mix proportion of geopolymer grouting material is proposed in this study, in which the replacement rate of GGBS is 45%; the modulus and concentration of modified sodium silicate activator are 1.5 and 75%, respectively; and the mass ratio of activator solution to solid is 1.5. In the recommended mix proportion, the geopolymer material has excellent comprehensive performance to implement grouting operation, in which the compressive and tensile strengths of the stone body reach 12.2 MPa and 0.8 MPa in 4 h, and reach 21.2 MPa and 2.1 MPa in 24 h. The fluidity is 223 mm, the initial setting and final setting times are 50 min and 57 min, the slurry stability of geopolymer material is good without liquid precipitation, in which the setting time is far less than 2 h. This work provides the experimental foundations for investigating the performance of geopolymer grouting material, which is also expected to provide reference for the further application and promotion of geopolymer materials used for grouting operations in rapid construction or repair work.

Keywords:

geopolymer material; varied mix proportion; working performance; ultra-early-stage mechanical strength; experimental investigation

1. Introduction

Grouting materials require not only high ultra-early-stage strength of the stone body, but also proper working performances, such as high fluidity and fast setting time, as well as good stability [1]. In comparison to conventional cementitious grouting materials, geopolymer is an excellent grouting material with obvious advantages of fast hardening and high early strength, as well as corrosion resistance and high temperature resistance [2,3,4], which is beneficial to reuse solid waste resources and can be adopted in infrastructure construction, such as tunneling work [5,6,7,8]. Moreover, geopolymer is a kind of inorganic cementitious material, developed from raw materials with rich aluminosilicate, as well as synthesized by the action of an alkali activator, in which the curing reaction of geopolymer is different from the hydration of portland cement. As mentioned above, the application of geopolymer material as grouting material also requires high strength slurry stone body as well as proper working performance, and the factors that affect the performance of geopolymer material are complex and diverse. Among them, the type of raw materials adopted in mix proportions is one of the main influencing factors, in which the commonly used raw materials include metakaolin, fly ash, and blast furnace slag at present, and the potential pozzolanic activities of different kinds of raw materials are quite different. In view of previous investigations, the alkali activator and ground granulated blast-furnace slag (GGBS), as well as metakaolin (MK), are dominant compositions of geopolymer at present [9,10,11,12]. The commonly used metakaolin and blast furnace slag have higher potential pozzolanic activities than fly ash [13,14], in which the content of Si and Al in metakaolin is higher as well as conducive to the polymerization reaction [14], and blast furnace slag contains some calcium ions as well as being conducive to the early strength of stones at the same time. Moreover, another major factor affecting the performance of geopolymer is the composition of the alkali activator, in which many alkaline solutions can realize alkali excitation reaction, whereas NaOH solution and water glass composite solution are commonly used as the alkali activator in consideration of economic benefits, process conditions, and actual effects. The existing literature has studied the influence of the alkali activator on the performance of geopolymer material. The systematical investigation of the content of sodium hydroxide, sodium silicate, and water in the alkali activator, influencing the mechanical properties of geopolymer material, has been realized, in which the mechanical properties of geopolymer material is firstly increased and then decreased with the increase of alkali equivalent [15,16].

As described above, the mechanical strength and its growth rate as well as the working performance of setting time and fluidity are the main influencing factors of geopolymer material used for grouting application. In view of previous literatures, several researchers have carried out relevant studies from different perspectives on using the advantages of geopolymer materials for grouting operation in the rapid construction or repairing work [17,18,19], which is expected to obtain geopolymer grouting materials with suitable working performance and high physical strength. The existing research demonstrate that the factors affecting the mechanical properties of geopolymer material have been studied to a certain extent, and the application of geopolymer as grouting material has also been explored accordingly. Especially, the aforementioned mechanical strength and working performances of geopolymer material are varied with different types of raw materials in mix proportions [9,20,21,22], such as the very high activator concentration, which can easily induce the flash coagulation of geopolymer, and the material performance can show different trends with the increased amount of activator in the range of different alkali excitation dosage [23,24,25]. However, there are relatively few factors affecting the performance in the current research of geopolymer-based grouting material unfortunately, and there is no corresponding research on ultra-early-stage mechanical performance of geopolymer material used for the rapid grouting reinforcement of broken rock mass within a few hours, at present. Therefore, the performance of geopolymer grouting material with varied mix proportions has not yet been clearly understood until now, which may lead to an incomplete performance of geopolymer material in grouting operation, and there is therefore, an urgent requirement for the further study of the performance of geopolymer material used for grouting reinforcement.

In this paper, the experimental investigation into the ultra-early-stage mechanical strength and the working performances of fluidity and setting times in geopolymer material is implemented with varied mass fractions of raw materials in mix proportions. The study focuses on the performance variation of geopolymer materials influenced by varied mass fractions of raw materials with different mix proportions [26,27,28,29], considering the influence of four factors of ground granulated blast-furnace slag (GGBS). Sodium silicate modulus, activator concentration, as well as the mass ratio of activator solution to solid in the different mix proportions [30,31,32], in which the metakaolin mixed with slag is used as raw material, sodium hydroxide, and sodium silicate composite solution are used as activators. The optimum mix proportion of geopolymer with excellent material properties is recommended and used for grouting operation in the process of rapid construction or repair work, since high mechanical performance within a few hours and the excellent working performance of geopolymer grouting material are required in the rapid grouting and reinforcement of broken rock mass. The study promotes the comprehensiveness of geopolymer performance and application research, and further explores the performance potential of geopolymers in the early stage. Additionally, the possibility of using geopolymer as a rapid grouting material for strengthening broken rock mass with excellent working performance, in which the slurry fluidity, viscosity, setting time, and water separation rate and other working properties, as well as ultra-early-stage (4 h, 8 h, 12 h, 16 h, 20 h, and 24 h) mechanical properties, including compressive strength and tensile strength, are studied through experimental tests.

2. Experiment Design of Geopolymer Material with Varied Mass Fractions of Raw Materials in Mix Proportions

The experiment is designed to investigate the performance variation of geopolymer material influenced by varied mass fractions of raw materials in different mix proportions, in which the geopolymer is made of dry powders mixed with alkali-activated solution.

2.1. Selected Raw Materials in Geopolymer

Figure 1 demonstrates the typical raw materials selected in the mix proportions, in which the dry powders are composed of metakaolin (MK) and ground granulated blast-furnace slag (GGBS). Table 1 shows the ingredients and mass fractions of the used compositions, GGBS and MK, in which GGBS is S95 level and MK is produced by Hunan Chaopai Technology Co., Ltd. Figure 2 demonstrates the granularity distribution of cumulative volume content versus particle size in the compositions of GGBS and MK. Moreover, the alkali-activator is made from the mixed solutions of sodium hydroxide and sodium silicate, in which the sodium hydroxide solution is produced using water and tablets with analytical purity, and the sodium silicate solution has 34% concentration with 3.3 molar ratio of SiO₂ to Na₂O.

2.2. Design of Experimental Scheme

Table 2 demonstrates the designed schemes of experimental investigation into the performance of geopolymer material with varied mass fractions of raw materials in mix proportions, including GGBS content (A), sodium silicate modulus (B), activator concentration (C), as well as the mass ratio of activator solution to solid (D), in which B and C are molar ratio of SiO₂ to Na₂O in sodium silicate solution and the mass ratio of modified sodium silicate solution to activator solution, respectively. The sodium silicate modulus (B) can be changed by adding NaOH flakes with analytically pure levels in the solution, and activator concentration (C) is varied by adjusting water in the mix proportion and keeping for 12 h thereafter. Moreover, variance analysis is implemented to clarify the experimental result, in which the variance is the difference between maximum and minimum values of the statistical data [32]. The three levels of GGBS content (A) are 25%, 35%, and 45%, respectively; those of sodium silicate modulus (B) are 1.3, 1.4, and 1.5, respectively; those of activator concentration (C) are 55%, 65%, and 75%, respectively, and those of the mass ratio of activator solution to solid (D) are 1.4, 1.5, and 1.6, respectively, which are determined with referencing to previously implemented tests.

2.3. Setup and Specimen Characteristics

Figure 3 shows the setup of a truncated circular die and a VICAT instrument, which were respectively adopted to test the fluidity and setting time of geopolymer material with varied mass fractions in mix proportion. The setting time of geopolymer material is recorded by VICAT instrument, and the fluidity of geopolymer material is determined as the maximum diameter of geopolymer material freely flowing on a glass plane over 30 s, which is tested by lifting the truncated circular die after fully filling with stirred grout.

Moreover, the compressive and flexural strengths of the stone body are also tested by a compression tester and a bending tester, in which all the specimens are cured in air condition with 20 ± 2 °C temperature. The bleeding rate of the geopolymer is determined using the measuring cylinder with 1000 mL capacity, in which the mixed batch of geopolymer is poured into the measuring cylinder with 850 mL volume. The initial height of geopolymer and height after keeping stationary for 2 h are recorded during the testing process, and the bleeding rate of geopolymer is accurately calculated by the following equation:

B = \frac{h_{0} - h_{1}}{h_{1}}

(1)

where B is the bleeding rate, h₀ and h₁ are the initial height and height after keeping stationary for 2 h.

3. Performance Variation of Geopolymer Material with Varied Mix Proportions

3.1. Test Results

In the performance requirements of grouting material for rapid grouting reinforcement of broken rock mass, the early mechanical strength and strength growth rate of the stone body are the most important indicators. In view of previous studies, some scholars have conducted relevant research from different perspectives on employing the advantages of rapid setting and early strength in geopolymer materials used for grouting operations. These were conducted to obtain grouting materials with an appropriate working performance and a high physical strength of stones, in which the obtained 1d maximum compressive strength of alkali-activated geopolymer slurry stone body was 5.53 MPa [33]. Table 3 shows the statistical analysis of compression and tensile strengths of slurry stone body from test results, in which 4 h, 8 h, 12 h, 16 h, 20 h, and 24 h represent 4 h, 8 h, 12 h, 16 h, 20 h, and 24 h; f_c and f_t are the compression and tensile strengths of geopolymer material, respectively. It can be seen that the maximum compressive and tensile strengths of the stone body after the solidification of geopolymer grout are 12.2 MPa and 0.8 MPa after 4 h, and the maximum compressive and tensile strengths are 21.2 MPa and 2.1 MPa after 24 h. As discussed above, the compressive strength of 4h slurry stone body obtained from this study can reach 12 MPa, which is obviously larger than the 1d maximum compressive strength of geopolymer slurry stone body with 5.53 MPa in the existing literature. Therefore, the mass fractions of raw materials in mix proportions proposed in this study have certain advantages from the perspective of early mechanical strength of slurry stone body.

Table 4 demonstrates the statistical analysis of slurry performance from test results. The good fluidity of the fresh grout is a necessary condition for grouting operation, and the maximum fluidity of the fresh grout is 231 mm. Moreover, the proper setting time represents the pumpability and timeliness of the slurry, and the proper time interval between the initial setting time and the final setting time is conducive to the subsequent construction process at the same time. It can be seen that the initial setting time of the slurry described in this paper ranges from 35 min to 62 min, the final setting time ranges from 46 min to 72 min, and the interval between the initial setting time and the final setting time ranges from 6 min to 15 min.

Based on the statistical analysis of the aforementioned mechanical strength and working performance, the optimal mix proportion of the geopolymer material is determined by comprehensively considering the significance of each index, in which the replacement rate of mineral powder is 45%, the modulus and concentration of the modified sodium silicate activator are 1.5 and 75%, respectively, and the mass ratio of activator solution to solid is 1.5.

3.2. Working Performance Variation

As one of the main performance indexes of grouting operation during the process of rapid construction or repairing work, fluidity affects the diffusion ability of geopolymer grouting material and also relates to the difficulty of grouting operation. Figure 4 demonstrates the fluidity variation of geopolymer influenced by varied mass fractions of raw materials in mix proportions, in which the influence from varied mass fractions of GGBS content (A), sodium silicate modulus (B), activator concentration (C), and the mass ratio of activator solution to solid (D) are studied. It can be clearly seen that all the fluidity results of the tested geopolymer materials are larger than 200 mm, which are little changed with the increasing content of sodium silicate modulus (B) and activator concentration (C); whereas those tend to gradually increase with the increasing mass ratio of activator solution to solid (D). Moreover, the geopolymer fluidities are increased with the increasing GGBS content (A), whereas the fluidity increment is reduced thereafter, in which the adsorbability of composite powder is relatively decreased with the increase of GGBS content (A), the metakaolin (MK) itself has strong adsorbability, and the free water in the slurry increases with a certain mass ratio of activator solution to solid (D), and then the fluidity of the slurry is thus increased.

Grout setting time is a key indicator of grouting operation in the process of rapid construction or repair work. Setting time that is too short is not conducive to field operation, which cannot guarantee the slurry diffusion range, since it is easy to cause blockage of grouting machines and tools. Through analysis of the initial setting time and final setting time of the slurry, the influence trend of each influencing factor on the setting time of the slurry is obtained. Figure 5 demonstrates the setting times variation in geopolymer with varied mass fractions of raw materials in mix proportions, in which the influence from varied mass fractions of GGBS content (A), sodium silicate modulus (B), activator concentration (C), and the mass ratio of activator solution to solid (D) are studied. It can be clearly seen geopolymer has the advantage of a short setting time far less than 2 h, in which the initial setting time is varied from 35 min to 62 min, and the final setting time is varied from 46 min to 72 min; the interval of both is ranged from 6 min to 15 min. There are few changes in both initial and final setting times with the increasing content of sodium silicate modulus (B) and activator concentration (C), whereas those are decreased with the increasing GGBS content (A). Especially, both initial and final setting times are first increased with the increasing mass ratio of activator solution to solid (D), whereas the time increment is reduced thereafter. This behavior is quite different from ordinary cement slurry. Moreover, the geopolymer has good stability without liquid precipitation in the experiment, which is probably due to the short setting time being far less than 2 h, as well as the water retaining capacity of metakaolin (MK) in geopolymer materials.

The mineral powder contains calcium ions, which have a stronger charge attraction than sodium ions. Therefore, the initial setting time and final setting time of the slurry are reduced with increasing GGBS content (A). In view of previous literature, the theoretical reaction model of the geopolymer includes three processes: dissolution, recombination, and polycondensation [34]. The coagulation time is the performance of the reaction rate to a certain extent, in which the dissolution, recombination, and polycondensation processes overlap each other when the activator concentration (C) is low, and the gel is wrapped around the undissolved aluminosilicate, inhibiting the reaction and resulting in an increase in the coagulation time. On the contrary, the reaction has an obvious sequence and the dissolution and polycondensation processes are clearly different when the activator concentration (C) is high, in which the reaction rate is also faster and the coagulation time is reduced [34]. The increase in the mass ratio of activator solution to solid (D) separates the distance between solid particles, and the spatial flocculation structure can’t be formed in time, which increases the coagulation time of geopolymer material.

This implies that both sodium silicate modulus (B) and activator concentration (C) have little effect on the working performance of geopolymer material. However, both GGBS content (A) and the mass ratio of activator solution to solid (D) have influence on the working performance of geopolymer material, in which the implemented variance analysis demonstrates that the fluidity is dominantly affected by the mass ratio of activator solution to solid (D), and the setting time is mainly influenced by GGBS content (A).

3.3. Mechanical Strength Variation

In the special requirements for rapid grouting reinforcement, the early mechanical strength of the slurry stone body is one of the most important indexes among all the performance indexes. Figure 6 demonstrates the compressive and tensile strengths in geopolymer material with varied mass fractions of raw materials in mix proportions, in which the influence from varied mass fractions of GGBS content (A), sodium silicate modulus (B), activator concentration (C), and the mass ratio of activator solution to solid (D) are studied. It can be clearly seen that there are few changes in the compressive and tensile strengths with the increasing content of sodium silicate modulus (B) and the mass ratio of activator solution to solid (D), whereas those are linearly increased with the increasing GGBS content (A) and activator concentration (C). This implies that both sodium silicate modulus (B) and the mass ratio of activator solution to solid (D) have little effect on the mechanical strength of geopolymer. However, both GGBS content (A) and activator concentration (C) have influence on the mechanical strength of geopolymer, in which the implemented variance analysis demonstrates that the mechanical strength is mainly affected by activator concentration (C) in the mix proportions.

4. Performance of Geopolymer Material with Recommended Mix Proportion

In view of the above experimental investigation, the aforementioned Scheme 7 in Table 2 is recommended as an optimum mix proportion of geopolymer material used for grouting operation in the process of rapid construction or repair work, in which GGBS content (A) and activator concentration (C) are 45% and 75%, respectively, sodium silicate modulus (B) is 1.3, and the mass ratio of activator solution to solid (D) is 1.5.

Figure 7 demonstrates the geopolymer material with recommended mix proportion, as well as the scanning electron microscope (SEM) image with 10,000 times, in which dense internal structure can be clearly observed in the geopolymer material with recommended mix proportion. Table 5 shows the working performance and mechanical strength of geopolymer with recommended mix proportion, in which the initial and final setting times are 49 min and 57 min, respectively, and the fluidity is 223 mm. This means the recommended geopolymer has good fluidity and an appropriate setting time for slurry diffusion in grouting operations. Moreover, the ultra-early-stage mechanical strength of the recommended geopolymer adequately satisfies the requirements of grouting reinforcement.

The performance of the slurry stone body left by the grout with good stability can ensure good homogeneity, and the slurry stability is also one of the key factors to ensure the effect of grouting operation in the process of rapid construction or repair work, in which the water separation rate is generally taken account by an index for calibrating the stability of slurry, and the slurry is considered as stable if the water separation rate is less than 5% within 2 h. Different from the traditional cement slurry, the setting time of the geopolymer grouting material in this study is far less than 2 h, in which the metakaolin in the composition system of the geopolymer grouting material has the characteristics of strong water retention, as well as being similar to that of kaolin at the same time, and the recommended geopolymer grouting material thus has good stability in this study.

5. Conclusions

In this paper, the experimental investigation into the performance variation of geopolymer grouting material with varied raw materials is implemented by employing the designed experimental schemes, in which the applicability, ultra-early-stage working performance, and mechanical performance of geopolymer material used for grouting operation in the process of rapid construction or repairing work are studied through tests with varied mix proportions. Range analysis is adopted to investigate the specific working performance of the fresh grout and the physical strength of the slurry stone body, as well as the performance impact of geopolymer grouting material induced by the substitution rate of ground granulated blast-furnace slag (GGBS), sodium silicate modulus, activator concentration, and the mass ratio of activator solution to solid. Moreover, the recommended mix proportion of geopolymer grouting material is proposed, the grouting performance of geopolymer material with optimal mix proportion is also presented, and the following conclusions can be drawn.

(1): Both sodium silicate modulus and activator concentration have little effect on the working performance of geopolymer, whereas both GGBS content and the mass ratio of activator solution to solid have influence on the working performance of geopolymer, in which the variance analysis demonstrates that the fluidity is dominantly affected by the mass ratio of activator solution to solid, and the setting time is mainly influenced by GGBS content.
(2): Both sodium silicate modulus and the mass ratio of activator solution to solid have little effect on the mechanical strength of geopolymer, whereas both GGBS content and activator concentration have influence on the mechanical strength of geopolymer, in which the variance analysis demonstrates that the mechanical strength is mainly affected by activator concentration.
(3): The geopolymer material with the recommended mix proportion has good fluidity and appropriate setting time for slurry diffusion in grouting operations and the ultra-early-stage mechanical strength of the recommended geopolymer material adequately satisfies the requirement of grouting application, in which a dense internal structure can be observed in the image obtained by scanning electron microscope (SEM).
(4): Considering the working performance of the fresh grout and the physical strength of the slurry stone body, the optimal mass fractions of raw materials in mix proportion of geopolymer material used for grouting operation is suggested, in which the replacement rate of mineral powder is 45%, sodium silicate modulus and activator concentration are 1.5 and 75%, respectively, and the mass ratio of activator solution to solid is 1.5.
(5): Compared with the traditional pure cement grout, the geopolymer grouting material has obvious advantages in rapid construction or repairing work, as well as green and environmental protection, mainly manifested in the strong early mechanical strength of the slurry stone body and excellent working performances of fluidity and setting time, as well as good stability without liquid precipitation, in which the setting time is far less than 2 h.
(6): In the recommended mix proportion, the geopolymer material has excellent comprehensive performance to implement grouting operation, in which the compressive and tensile strengths of the stone body reach 12.2 MPa and 0.8 MPa in 4 h, and those reach 21.2 MPa and 2.1 MPa in 24 h. The fluidity is 223 mm, the initial setting and final setting times are 50 min and 57 min, respectively, and the slurry stability of geopolymer material is good. Specifically, the aforementioned 4 h compressive strength of slurry stone body in the geopolymer grouting material with recommended mix proportion can reach 12.2 MPa, which has an obvious advantage over existing geopolymer material.

Author Contributions

Conceptualization, J.L., H.F. and Y.Z.; validation, J.L., H.F. and K.Z.; investigation, J.L. and H.F.; data curation, J.L. and H.F.; writing—original draft preparation, J.L.; writing—review and editing, H.F. and Y.Z.; supervision, Y.Z.; funding acquisition, J.L. and K.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Natural Science Foundation of Jiangsu Province (No. BK20211281), Postgraduate Research and Practice Innovation Program of Jiangsu Province (KYCX22_1060), Six Talent Peak Projects and Open Fund Project from Key Laboratory of Concrete and Pre-stressed Concrete Structure of Ministry of Education (Southeast university) (CPCSME2018-10).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data used to support the findings of this study are available from the corresponding author upon request.

Conflicts of Interest

The authors declare that there are no conflicts of interest regarding the publication of this paper.

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Figure 1. Typical raw materials selected in geopolymer material.

Figure 2. Granularity distribution in the compositions of MK and GGBS.

Figure 3. Setup of truncated circular die and VICAT instrument.

Figure 4. Geopolymer fluidity with varied mass fractions of raw materials in mix proportion.

Figure 5. Setting times with varied mass fractions of raw materials in mix proportion.

Figure 6. Mechanical strength with varied mass fractions of raw materials in mix proportion. (a) Compressive strength variation. (b) Tensile strength variation.

Figure 7. Recommended geopolymer material and SEM image. (a) Geopolymer material with recommended mix proportion. (b) SEM image at 10,000 times.

Table 1. Ingredients of metakaolin and ground granulated blast-furnace slag.

	Mass Fraction of Compositions (%)
MK	SiO₂	Al₂O₃	Na₂O	TiO₂	K₂O	MgO	Fe₂O₃	CaO	LOI
MK	44.29	37.22	0.62	0.5	0.13	0.14	0.36	0.39	14.98
GGBS	CaO	SiO₂	Al₂O₃	MgO	SO₃	TiO₂	MnO	Fe₂O₃	K₂O
GGBS	36.91	33.98	15.22	9.27	1.81	0.80	0.59	0.62	0.41

Table 2. Designed schemes of experimental investigation.

Scheme	Factor Compositions
Scheme	A	B	C	D
1	25%	1.3	55%	1.4
2	25%	1.4	65%	1.5
3	25%	1.5	75%	1.6
4	35%	1.3	65%	1.6
5	35%	1.4	75%	1.4
6	35%	1.5	55%	1.5
7	45%	1.3	75%	1.5
8	45%	1.4	55%	1.6
9	45%	1.5	65%	1.4

Table 3. Statistical analysis of compression and flexure strengths of stone body from test results.

Scheme	4 h (MPa)		8 h (MPa)		12 h (MPa)		16 h (MPa)		20 h (MPa)		24 h (MPa)
Scheme	f_c	f_t	f_c	f_t	f_c	f_t	f_c	f_t	f_c	f_t	f_c	f_t
1	1.8	0.5	2.4	0.5	1.7	0.6	2.5	0.6	2.3	0.7	2.2	1.2
2	4.4	0.2	6.1	0.6	6.1	0.9	7.4	1.3	7.6	1.3	9.6	1.6
3	5.1	0.8	7.2	0.9	8.5	1.2	10.8	1.6	12.2	1.8	13.4	2.0
4	4.2	0.7	5.3	1.1	6.0	1.2	7.1	1.4	9.3	1.6	10.8	1.7
5	7.6	0.7	9.5	0.9	10.2	1.2	14.2	1.5	16.8	2.0	18.6	2.3
6	1.4	0.3	1.8	0.5	2.1	0.6	2.2	0.8	3.5	0.9	3.8	1.0
7	12.2	0.8	14.1	1.2	18.0	1.7	19.5	1.9	20.8	2.0	21.2	2.1
8	0.5	0.5	0.9	0.6	1.4	0.7	2.0	0.8	3.4	1.2	4.1	1.4
9	6.2	1.1	8.9	1.2	10.1	1.6	11.8	1.6	12.7	1.7	14.1	1.8

Table 4. Statistical analysis of slurry performance from test results.

Scheme	Factor Compositions				Fluidity (mm)	Setting Time (min)
Scheme	A	B	C	D	Fluidity (mm)	Initial Setting	Final Setting
1	0.25	1.3	55%	1.4	201	54	63
2	0.25	1.4	65%	1.5	208	56	65
3	0.25	1.5	75%	1.6	215	59	66
4	0.35	1.3	65%	1.6	227	52	60
5	0.35	1.4	75%	1.4	212	48	54
6	0.35	1.5	55%	1.5	221	58	63
7	0.45	1.3	75%	1.5	223	50	57
8	0.45	1.4	55%	1.6	229	54	61
9	0.45	1.5	65%	1.4	213	46	54

Table 5. Working performance and mechanical strength of recommended geopolymer material.

Composition				Fluidity (mm)	Setting Time (min)		Strength (MPa)
Composition					Setting Time (min)		Compressive		Tensile
A	B	C	D		Initial	Final	4 h	24 h	4 h	24 h
45%	1.3	75%	1.5	223	49	57	12.2	21.2	0.8	2.1

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Liu, J.; Feng, H.; Zhang, Y.; Zheng, K. Performance Investigation of Geopolymer Grouting Material with Varied Mix Proportions. Sustainability 2022, 14, 13046. https://doi.org/10.3390/su142013046

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Liu J, Feng H, Zhang Y, Zheng K. Performance Investigation of Geopolymer Grouting Material with Varied Mix Proportions. Sustainability. 2022; 14(20):13046. https://doi.org/10.3390/su142013046

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Liu, Jianwei, Han Feng, Yongxing Zhang, and Kaiqi Zheng. 2022. "Performance Investigation of Geopolymer Grouting Material with Varied Mix Proportions" Sustainability 14, no. 20: 13046. https://doi.org/10.3390/su142013046

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Liu, J., Feng, H., Zhang, Y., & Zheng, K. (2022). Performance Investigation of Geopolymer Grouting Material with Varied Mix Proportions. Sustainability, 14(20), 13046. https://doi.org/10.3390/su142013046

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