Next Article in Journal
Can Environmental, Social, and Governance Ratings Promote Green Innovation in Chinese Heavy Polluters? Perspectives from “Greening” Behaviors
Previous Article in Journal
Why Do Some Countries Innovate Better than Others? A New Perspective of Science, Technology, and Innovation Policy Regimes and National Absorptive Capacity
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Sustainability
Volume 16
Issue 7
10.3390/su16072841
sustainability-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Impact of Alkaline Concentration on the Mechanical Properties of Geopolymer Concrete Made up of Fly Ash and Sugarcane Bagasse Ash

by
Mohammed Ali M. Rihan
1,2,*,
Turki S. Alahmari
3,
Richard Ocharo Onchiri
4,
Naftary Gathimba
5 and
Bernadette Sabuni
6
1
Pan African University Institute for Basic Sciences, Technology, and Innovation, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O. Box 62000-00200, Kenya
2
Civil Engineering Department, Faculty of Engineering, University of Kordofan, El Obeid 51111, Sudan
3
Department of Civil Engineering, Faculty of Engineering, University of Tabuk, P.O. Box 741, Tabuk 71491, Saudi Arabia
4
Department of Building and Civil Engineering, Technical University of Mombasa (TUM), Mombasa P.O. Box 90420-80100, Kenya
5
Department of Civil, Construction and Environmental Engineering, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O. Box 62000-00200, Kenya
6
Department of Civil and Structural Engineering, Masinde Muliro University of Science and Technology, Kakamega P.O. Box 190 50100, Kenya
*
Author to whom correspondence should be addressed.
Sustainability 2024, 16(7), 2841; https://doi.org/10.3390/su16072841
Submission received: 17 February 2024 / Revised: 15 March 2024 / Accepted: 26 March 2024 / Published: 28 March 2024
Browse Figures
Versions Notes

Abstract

:
Geopolymer concrete (GPC) is a novel and environmentally friendly type of concrete that eliminates the use of cement, resulting in a significant reduction in carbon emissions and a more sustainable construction material. Alkaline activators are used in GPC to achieve rapid strength development. The most popular alkaline activators are sodium/potassium silicate and sodium/potassium hydroxide, which are known contributors to carbon emissions, hence limiting the advantages of GPC; therefore, reducing the amount of these alkaline activators that contribute to carbon emissions is necessary for developing a more sustainable geopolymer concrete. In this study, the influence of the variation in sodium hydroxide molarities on the performance of fly ash/sugarcane bagasse ash-based-geopolymer concrete was investigated. The different molarities used were 10 M, 12 M, 14 M, and 16 M sodium hydroxide solutions. In addition, the effect of sugarcane bagasse ash content (0%, 5%, 10%, 15%, and 20%) on the fresh and hardened geopolymer concrete properties were examined. The slump test, compression test, split tensile test, and flexure test were conducted on the cast samples. The results of this study showed that raising the concentration of NaOH from 10 M to 16 M while maintaining a sodium silicate to sodium hydroxide ratio of 2.5 resulted in a 3.75–10.2% improvement in compressive strength after 28 days. It is worth noting that, even at a concentration of 10 M, the concrete still achieved high strength.

1. Introduction

Concrete is one of the most frequently utilized building materials, and Portland cement commonly features as one of its primary components. Because of increased urbanization and industrialization, there is increased demand for extensive infrastructural development, requiring more concrete as a construction material. In 2021, cement production reportedly reached 4.4 billion tons worldwide [1,2], and the annual concrete consumption is forecasted to pass 18 billion tons by 2050 [3]. The manufacture of Portland cement (PC) used in concrete has substantial effects on the environment in terms of high energy use, natural resource depletion, and carbon dioxide (CO2) emissions [4,5,6]. The cement manufacturing industries contribute roughly 7% of global CO2 emissions [7,8,9,10,11]. This environmental effect could be minimized by using less cement in concrete production or by developing a strategy for lowering CO2 emissions. This strategy includes finding ecologically suitable materials to replace Portland cement, preferably utilizing waste byproduct materials [12,13].
In the construction sector, low carbon concrete, also known as geopolymer concrete (GPC), should be preferred over Portland cement concrete due to the essential roles it can play in waste disposal, carbon dioxide emission reduction, durability, and environmental compatibility [14,15]. This inorganic alumino-silicate geopolymer has been invented and is being suggested as a PC substitute in the construction industry [16]. Alkali activation is used to make the geopolymer from geological or byproduct materials rich in silicon and aluminum, such as ground granulated blast furnace slag (GGBFs), fly ash (FA), and metakaolin [17]. In addition to having a low environmental consequence, geopolymer concrete has superior properties, including good resistance to attacks from acids and sulfates, high early age strength, low setting time, minimal shrinkage, resistance to fire, and low heat conductivity [8,10,18]. In addition to its durability and mechanical performance, GPC has good thermal resistance and can withstand temperatures as high as 1200 °C without experiencing any sudden degradation [19]. The expression “geopolymer” refers to a category of materials formed through the reaction of an alkali activator to aluminosilicate powder [20,21]. Davidovits, in 1978, was the one who first presented geopolymers to the scientific community as a novel class of binders that belonged to inorganic polymers [22,23].
Industrial byproducts, such as fly ash (FA) and sugarcane bagasse ash (SCBA), have been found to contain aluminosilicates that can be used to manufacture geopolymer concrete. About 60% of FA produced in thermal power stations is deposited in landfills [11,24]. On the other hand, SCBA is a globally available byproduct made by burning bagasse to produce energy in boilers [25,26]. The estimated annual output of SCBA is predicted to range from 48 to 60 million tonnes, depending on the yield [27], and these substances pollute the environment when dumped. One can obtain sugarcane bagasse with good pozzolanic characteristics by burning it for 20 min at 800–1000 °C [28,29] or 3 h of air calcining at 600 °C [30]. The percentage of silica in the ash varies based on temperature, the kind of soil in which the sugarcane is grown, and the burning method [31,32].
One of the crucial parameters for influencing GPC performance is the concentration of alkali activator (i.e., sodium hydroxide) present. As a result, several studies have been undertaken to determine the effect of alkali concentration. Verma and Dev [33] investigated how sodium hydroxide affected the mechanical characteristics of GPC made with FA and slag, with their findings indicating that, when the sodium hydroxide molarity increases, the mix design’s compressive strength increases to an optimum value for the oven-cured specimens. Ghafoor et al. [34] assessed the impact of activators on the compressive strength of GPC cured at normal temperature. Their findings indicate that the strength initially increased when the sodium hydroxide molarity rose to 14 M but then subsequently declined. Investigations by Alghannam et al. [35] showed that the compressive strength decreased as the molarity was elevated from 14 M to 20 M. Pratap et al. [11] investigated the effect of sodium hydroxide molarity on the compressive strength of GPC prepared with FA and phosphogypsum. The findings indicated that the strength characteristics rose with increasing molar concentration, with a peak at 12 M, and then fell as sodium hydroxide concentration continued to rise. H.M. and Unnikrishnan [36] also studied the mechanical strength of GGBFs-SCBA-based GPC. They observed that all the mixtures’ mechanical strength characteristics improved when molarity rose to 12 M from 8 M.
Research has demonstrated promising results in utilizing industrial and agricultural byproducts such as FA, GGBS, metakaolin, rice husk ash, and corncob ash for geopolymer concrete development. However, there is minimal available research on the performance of sustainable geopolymer concrete that relies only on FA and SCBA. Alkaline activators are the main cause of carbon emissions in geopolymer concrete manufacturing. As a result, lowering the amount of these components that contribute to carbon emissions is essential for the development of a more sustainable geopolymer concrete. Lowering the molarity of alkaline activator in geopolymer concrete can significantly improve sustainability by reducing the quantities consumed; however, this contradicts the common idea of increasing molarity to enhance strength. The reduction in molarity of NaOH is expected to provide further benefits, such as lower economic costs and convenience of handling. The primary objective of the present study is to investigate the influence of NaOH molarity from 10 to 14 M on the strength of geopolymer concrete containing FA and different percentages of SCBA. The slump test, compressive strength, split tensile strength, and flexural strength of the resulting geopolymer concrete mixes were evaluated.

2. Materials and Methods

2.1. Materials Acquisition and Preparation

The materials utilized in this investigation included SCBA, FA, fine and coarse aggregate, superplasticizer, and an alkaline solution containing sodium hydroxide and sodium silicates. FA was supplied from India, while SCBA was acquired from Sukari Industries Ltd., in Western Kenya. Sugarcane ash was sieved through a 75 μm mesh screen to reach the necessary particle size and eliminate residual carbonaceous elements and large particles. After that, the loss of ignition (LOI) was assessed. The unprocessed SCBA has a LOI of 10.20%. To comply with ASTM C618, the raw SCBA was re-burned for four hours at 650 °C in a muffle furnace to lower the LOI below 6%. X-ray fluorescence (XRF) examination was used to assess the chemical compositions of FA and SCBA, with the outcomes being shown in Table 1. The specific gravity of FA and SCBA were 2.5 and 2.2, respectively.
Figure 1 shows the X-ray diffraction (XRD) pattern of FA and SCBA. The main FA’s mineralogical phases were quartz, chlorite, and muscovite, while SCBA has more quartz phases than FA. Figure 2 illustrates the scanning electron microscopy (SEM) graphics of the FA and SCBA, which provide a more intricate depiction of the particle’s structure. The SCBA particles were found to be shaped like fibrous and irregular flakes, and they feature round surface capillary pores.
The crushed stone used as coarse aggregate had a specific gravity of 2.66 and a maximum aggregate size of 12.5 mm. The fine aggregate was a mixture of quarry dust (30%) and river sand (70%) that had been sieved through an ASTM 0.18 mm filter, followed by oven drying for 24 h at 105 °C. The properties of the aggregates are presented in Table 2. Figure 3 depicts the distribution of particle sizes in the aggregate. A combination of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) was utilized as the alkaline activator in this study. Na2SiO3 was employed in solution form with a specific gravity of 1.530 at 20 °C and a Na2O:SiO2 ratio of 1:2.10 (Na2O of 13.76% and SiO2 of 28.9). The NaOH pearls used in the study had a purity of at least 99%.

2.2. Mix Proportions, Mixing, Casting and Curing

Table 3 displays the different mix proportions of geopolymer concrete used in this investigation, including SCBA and FA. The mixed variables consisted of the proportion of SCBA used as a substitute for fly ash, measured by mass. Additionally, the concentration of NaOH (ranging from 10–16 M) was also considered. The ratio of Na2SiO3 to NaOH has been taken to be 2.5 and 1.5, which could result in maximum compressive strengths [34,37,38]. In this investigation, the mixing technique adopted began by combining the SCBA, FA, and aggregates with the NaOH solution in order to dissolve the aluminum and silicon found in the unprocessed material. Then, Na2SiO3 solution was added to increase the binding strength [39], as this approach could result in greater strength in comparison to alternative production methods [40]. In detail, the dried aggregate, FA, and SCBA were combined in the mixer for three minutes. Then, the NaOH solution was progressively added and mixed for another three minutes. To guarantee perfect homogeneity, the wet mix was treated with Na2SiO3 solution and mixed for a further five minutes. A superplasticizer was added to enhance workability. Following the process of mixing, the GPC was poured into several molds to form cubes, cylinders, and beam specimens. Specimens were then cured at a high temperature of 80 °C in an oven for 24 h in order to accelerate the geopolymerization process while enhancing the concrete’s physical and mechanical properties.

2.3. Testing Specimens

Compressive strength testing was achieved in line with the BS EN [41] BS EN 12390-03 standard. A universal compression test machine with a 1500 kN capacity was used to test the cube samples. Three cubes for each mix were tested. ASTM [42] ASTM C 496/C 496 M 04 standards were employed to measure the tensile strength of the geopolymer concrete after 28 days of the curing period. The average of three cylinder readings for each mixture was taken. In accordance with the ASTM [43] ASTM C78-02 standard, the flexural strength was evaluated after curing for a period of 28 days.

3. Results and Discussion

3.1. Workability

The effect of the molarity of the NaOH solution on the workability of fly ash−sugarcane bagasse ash-based GPC is illustrated in Figure 4. These graphs show that the slump is lowered when the sodium hydroxide solution’s molarity is increased. This is the same trend as reported by Naenudon et al. [44]. Utilization of a higher concentration of NaOH solution resulted in increased alumina and silica leaching from FA and SCBA, and hence caused the mixture’s viscosity to rise [45,46]. Furthermore, the decrease in water contents in an alkaline solution with the increase in NaOH molarity resulted in a decline of GPC workability [47,48]. It is worth mentioning that the slump values that were recorded for each of the combinations exhibited satisfactory workability.

3.2. Compressive Strength

The compressive strength of geopolymer concrete mixes containing 10 M, 12 M, 14 M, and 16 M after 28 days of curing are displayed in Figure 5a,b, respectively. According to the test results, the compressive strength of the GPC mixes increased when the molarity of the NaOH solution was increased from 10 to 16 M for a Na2SiO3/NaOH ratio of 2.5. However, for mixtures containing 0% and 15% of SCBA, the strength decreased after 14 M, although the decrease was not substantial, which is similar to what several researchers have reported [33,35]. Alghannam et al. [35] found that the compressive strength declined as the molarity of NaOH increased from 14 to 20 M, indicating that the correlation between molarity and compressive strength aligns with prior research [49,50]. Meanwhile, as the molarity of NaOH rose from 10 to 16 M, with a Na2SiO3/NaOH ratio of 1.5, it resulted in an overall improvement in compressive strength, even though a slight drop was observed at 12 M. The observed variation in compressive strength clearly demonstrates the influence of NaOH molarity on GPC. The reason behind this is that sodium hydroxide creates the alkaline environment that geopolymer gels need to bind together [51,52,53]. Raising the concentration of NaOH can speed up the breakdown of aluminosilicates, encouraging the quick creation of geopolymer gels and the attainment of superior compressive strength [33,54,55,56]. The reduction in strength can be ascribed to the delay of geopolymerization induced by an overabundance of soluble silicates, specifically when the molar concentration surpasses 12 M or 14 M [33], resulting in the extraction of the Al3+ and Si4+ ions by leaching [57]. This may have potentially compromised the synthesis of C-A-S-H and N-A-S-H gel structures, consequently resulting in a fall in the material’s strength [58].
Finally, the compressive strength of GPC composites is enhanced as the molarity of NaOH is increased. This effect is due to the breakdown of aluminum and silicon particles throughout the polymerization process [59], consequently contributing to the enhancement of the compressive strength of geopolymer concrete mixtures [47].

3.3. Tensile Strength

Figure 6 depicts the tensile strength of GPC investigated after 28 days of curing. The tensile strength of GPC obtained using 10 M, 12 M, 14 M, and 16 M mixes showed a comparable tendency to that of compressive strength at all replacement levels. The tensile strength rises from 15.5% to 61% when the molarity is raised from 10 to 14 M. Molar concentrations are essential for increasing strength during polymerization. The increase in molarity raises the matrix’s pH, which promotes the development of the amorphous phase. Lower dissolution of Si4+ and Al3+ ions causes a decrease in matrix strength growth when the molarity ratio is smaller [60]. The higher splitting tensile strength is a result of increased silica and alumina dissolution. Beyond a certain point, additional increases in molarity result in a decline in GPC strength [61,62].

3.4. Flexural Strength

The 28-day flexural strength of fly ash−sugarcane bagasse ash-based GPC is shown in Figure 7. The findings indicate that, in all cases, flexural strength tends to decrease as SCBA content substitution increases. As the molarity of NaOH rises, the flexural strength value increases up to 14 M and then declines at 16 M. With the molarity rising to 14 M, the flexural strength increases from 17.3 to 40%. This is because a higher concentration of sodium hydroxide promotes better alumina and silica leaching, which improves geopolymerization and increases strength.

3.5. Correlation between the Mechanical Properties

In this section, a regression analysis was conducted with the aid of the Origin Pro program in order to determine the correlation between the splitting tensile strength and compressive strength, as well as flexural strength with compressive strength.

3.5.1. Splitting Tensile Strength vs. Compressive Strength

Table 4 shows the models that have been proposed to explain the relation between the splitting tensile strength and the compressive strength of geopolymer concrete composed of fly ash and sugarcane bagasse ash. The equations for the proposed model have been constructed for a mean compressive strength ranging from 47 to 75 MPa. The equations that are proposed for the model are represented as Equations (1)–(8).
Figure 8 illustrates the correlation between the splitting tensile strength and compressive strength of geopolymer concrete. It shows that the coefficient of determination (R2) for all models of 10, 12, and 16 M was 94% fit to forecast the connection of 94% confidence bound of compressive strength. The correlation established in this experiment is comparable to Alomayri et al. [63] and Zareei et al. [64], where the R2 for the relation between tensile strength and compressive strength were 92 and 94%, respectively. As a result, the derived model equations can be utilized to forecast the compressive strength of FA-SCBA-based GPC between 47 and 75 MPa.

3.5.2. Flexural Strength vs. Compressive Strength

Table 5 shows the models that have been proposed to explain the relationship between the flexural strength and compressive strength of GPC that is based on FA-SCBA. The equations for the proposed model have been constructed for a mean compressive strength ranging from 47 to 75 MPa. The equations that are proposed for the model are represented as Equations (9)–(16).
As can be seen in Figure 9, the relationship between the compressive strength and the flexural strength of GPC demonstrates that the coefficient of determination (R2) of the models was 93 percent. This indicates that the models were able to accurately predict the connection with 93% confidence. Therefore, the model equations generated can be used to forecast the 47–75 MPa compressive strength of FA-SCBA-based geopolymer concrete, given the flexural strength.

4. Conclusions

In this study, the impact of sodium hydroxide molarity on fly ash−sugarcane bagasse ash-based geopolymer concrete was explored. Based on the investigation carried out, the sodium hydroxide molarity plays a vital role in the compressive strength, splitting strength, and flexural strength of geopolymer concrete samples. From the investigations, the following can be concluded:
1-
An increase in the molarity of the sodium hydroxide solution decreases the slump because the higher concentration of the sodium hydroxide solution enhanced the leaching of silica and alumina from GPC, which raised the mixture’s viscosity and lowered its water content. Remarkably, the reported slump values for all combinations demonstrated acceptable workability.
2-
Increasing the molarity of NaOH in the mix increases the compressive strength; however, the compressive strength decreases after a certain point. This is because sodium hydroxide produces the alkaline environment that geopolymer gels require to bind together.
3-
Increasing the NaOH concentration can accelerate the aluminosilicates’ breakdown, promoting the rapid formation of geopolymer gels and achieving excellent compressive strength.
4-
The splitting tensile strength of fly ash−sugarcane bagasse ash-based GPC produced with 10, 12, 14, and 16 M mixes has demonstrated a comparable pattern to compressive strength at all the replacement levels in most cases.
5-
The flexural strength decreased as the substitution of SCBA concentration increased. As the concentration of NaOH increased, the flexural strength value initially increased to 14 M and subsequently decreased at 16 M.
6-
The findings of the regression analysis demonstrated that there was a substantial correlation between the suggested model equations and the experimental data.
The results will be valuable as the utilization of sugarcane bagasse ash appears to positively impact the strength properties of GPC, supporting its potential as a sustainable construction material. However, future studies should investigate the impact of low molarity on the mechanical properties and long-term durability of geopolymer concrete made from fly ash and sugarcane bagasse ash.

Author Contributions

The article was written with the collaboration of all the contributors. All the authors contributed equally to the scientific information collection, analysis of the data, writing and editing of the article, as well as to the concept design and study proposal. All authors have read and agreed to the published version of the manuscript.

Funding

The authors appreciate and acknowledge that African Union financially support this research.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data will be available upon request.

Acknowledgments

The authors would like to express their gratitude to Pan African University, Institute for Basic Science, Technology, and Innovation, Department of Civil Engineering, and Jomo Kenyatta University of Agriculture and Technology for their technical assistance of this research. Also, the authors wish to express their deep gratitude to the University of Kordofan and the University of Tabuk.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Abbas, S.N.; Qureshi, M.I.; Abid, M.M.; Zia, A.; Tariq, M.A.U.R. An Investigation of Mechanical Properties of Fly Ash Based Geopolymer and Glass Fibers Concrete. Sustainability 2022, 14, 10489. [Google Scholar] [CrossRef]
  2. Alahmari, T.S.; Abdalla, T.A.; Rihan, M.A.M. Review of Recent Developments Regarding the Durability Performance of Eco-Friendly Geopolymer Concrete. Buildings 2023, 13, 3033. [Google Scholar] [CrossRef]
  3. Alawi Al-Sodani, K.A. Mix design, mechanical properties and durability of the rubberized geopolymer concrete: A review. Case Stud. Constr. Mater. 2022, 17, e01480. [Google Scholar] [CrossRef]
  4. Haddad, R.H.; Alshbuol, O. Production of geopolymer concrete using natural pozzolan: A parametric study. Constr. Build. Mater. 2016, 114, 699–707. [Google Scholar] [CrossRef]
  5. Moradikhou, A.B.; Safehian, M.; Golafshani, E.M. High-strength geopolymer concrete based on coal washing waste. Constr. Build. Mater. 2023, 362, 129675. [Google Scholar] [CrossRef]
  6. Luhar, S.; Cheng, T.-W.; Nicolaides, D.; Luhar, I.; Panias, D.; Sakkas, K. Valorisation of glass wastes for the development of geopolymer composites—Durability, thermal and microstructural properties: A review. Constr. Build. Mater. 2019, 222, 673–687. [Google Scholar] [CrossRef]
  7. Shumuye, E.D.; Zhao, J.; Wang, Z. Effect of the Curing Condition and High-Temperature Exposure on Ground-Granulated Blast-Furnace Slag Cement Concrete. Int. J. Concr. Struct. Mater. 2021, 15, 15. [Google Scholar] [CrossRef]
  8. Zhao, J.; Wang, K.; Wang, S.; Wang, Z.; Yang, Z.; Shumuye, E.D.; Gong, X. Effect of Elevated Temperature on Mechanical Properties of High-Volume Fly Ash-Based Geopolymer Concrete, Mortar and Paste Cured at Room Temperature. Polymers 2021, 13, 1473. [Google Scholar] [CrossRef] [PubMed]
  9. Kotop, M.A.; El-Feky, M.S.; Alharbi, Y.R.; Abadel, A.A.; Binyahya, A.S. Engineering properties of geopolymer concrete incorporating hybrid nano-materials. Ain Shams Eng. J. 2021, 12, 3641–3647. [Google Scholar] [CrossRef]
  10. Assi, L.N.; Deaver, E.; ElBatanouny, M.K.; Ziehl, P. Investigation of early compressive strength of fly ash-based geopolymer concrete. Constr. Build. Mater. 2016, 112, 807–815. [Google Scholar] [CrossRef]
  11. Pratap, B.; Mondal, S.; Hanumantha Rao, B. NaOH molarity influence on mechanical and durability properties of geopolymer concrete made with fly ash and phosphogypsum. Structures 2023, 56, 105035. [Google Scholar] [CrossRef]
  12. Nagajothi, S.; Elavenil, S.; Angalaeswari, S.; Natrayan, L.; Mammo, W.D.; Putra Jaya, R. Durability Studies on Fly Ash Based Geopolymer Concrete Incorporated with Slag and Alkali Solutions. Adv. Civ. Eng. 2022, 2022, 7196446. [Google Scholar] [CrossRef]
  13. Alnahhal, M.F.; Alengaram, U.J.; Jumaat, M.Z.; Abutaha, F.; Alqedra, M.A.; Nayaka, R.R. Assessment on engineering properties and CO2 emissions of recycled aggregate concrete incorporating waste products as supplements to Portland cement. J. Clean. Prod. 2018, 203, 822–835. [Google Scholar] [CrossRef]
  14. Amran, M.; Al-Fakih, A.; Chu, S.H.; Fediuk, R.; Haruna, S.; Azevedo, A.; Vatin, N. Long-term durability properties of geopolymer concrete: An in-depth review. Case Stud. Constr. Mater. 2021, 15, e00661. [Google Scholar] [CrossRef]
  15. Amran, M.; Debbarma, S.; Ozbakkaloglu, T. Fly ash-based eco-friendly geopolymer concrete: A critical review of the long-term durability properties. Constr. Build. Mater. 2021, 270, 121857. [Google Scholar] [CrossRef]
  16. Hardjito, D.; Wallah, S.E.; Sumajouw, D.M.J.; Rangan, B.V. On the Development of Fly Ash-Based Geopolymer Concrete. ACI Mater. J. 2004, 101, 467–472. [Google Scholar] [CrossRef]
  17. Amin, M.; Elsakhawy, Y.; Abu el-hassan, K.; Abdelsalam, B.A. Behavior evaluation of sustainable high strength geopolymer concrete based on fly ash, metakaolin, and slag. Case Stud. Constr. Mater. 2022, 16, e00976. [Google Scholar] [CrossRef]
  18. Duxson, P.; Fernández-Jiménez, A.; Provis, J.L.; Lukey, G.C.; Palomo, A.; van Deventer, J.S.J. Geopolymer technology: The current state of the art. J. Mater. Sci. 2007, 42, 2917–2933. [Google Scholar] [CrossRef]
  19. Part, W.K.; Ramli, M.; Cheah, C.B. An overview on the influence of various factors on the properties of geopolymer concrete derived from industrial by-products. Constr. Build. Mater. 2015, 77, 370–395. [Google Scholar] [CrossRef]
  20. Chindaprasirt, P.; Chalee, W. Effect of sodium hydroxide concentration on chloride penetration and steel corrosion of fly ash-based geopolymer concrete under marine site. Constr. Build. Mater. 2014, 63, 303–310. [Google Scholar] [CrossRef]
  21. Aslani, F.; Asif, Z. Properties of Ambient-Cured Normal and Heavyweight Geopolymer Concrete Exposed to High Temperatures. Materials 2019, 12, 740. [Google Scholar] [CrossRef]
  22. Davidovits, J. Geopolymers. J. Therm. Anal. 1991, 37, 1633–1656. [Google Scholar] [CrossRef]
  23. Ekinci, E.; Türkmen, İ.; Kantarci, F.; Karakoç, M.B. The improvement of mechanical, physical and durability characteristics of volcanic tuff based geopolymer concrete by using nano silica, micro silica and Styrene-Butadiene Latex additives at different ratios. Constr. Build. Mater. 2019, 201, 257–267. [Google Scholar] [CrossRef]
  24. Rashidian-Dezfouli, H.; Rangaraju, P.R. Study on the effect of selected parameters on the alkali-silica reaction of aggregate in ground glass fiber and fly ash-based geopolymer mortars. Constr. Build. Mater. 2021, 271, 121549. [Google Scholar] [CrossRef]
  25. El-said, A.; Awad, A.; Ahmad, M.; Sabri, M.M.S.; Deifalla, A.F.; Tawfik, M. The Mechanical Behavior of Sustainable Concrete Using Raw and Processed Sugarcane Bagasse Ash. Sustainability 2022, 14, 11181. [Google Scholar] [CrossRef]
  26. Abdalla, T.A.; Koteng, D.O.; Shitote, S.M.; Matallah, M. Mechanical and durability properties of concrete incorporating silica fume and a high volume of sugarcane bagasse ash. Results Eng. 2022, 16, 100666. [Google Scholar] [CrossRef]
  27. Torres de Sande, V.; Sadique, M.; Pineda, P.; Bras, A.; Atherton, W.; Riley, M. Potential use of sugar cane bagasse ash as sand replacement for durable concrete. J. Build. Eng. 2021, 39, 102277. [Google Scholar] [CrossRef]
  28. Jha, P.; Sachan, A.K.; Singh, R.P. Agro-waste sugarcane bagasse ash (ScBA) as partial replacement of binder material in concrete. Mater. Today Proc. 2021, 44, 419–427. [Google Scholar] [CrossRef]
  29. Chindaprasirt, P.; Sujumnongtokul, P.; Posi, P. Durability and Mechanical Properties of Pavement Concrete Containing Bagasse Ash. Mater. Today Proc. 2019, 17, 1612–1626. [Google Scholar] [CrossRef]
  30. Sua-iam, G.; Makul, N. Use of increasing amounts of bagasse ash waste to produce self-compacting concrete by adding limestone powder waste. J. Clean. Prod. 2013, 57, 308–319. [Google Scholar] [CrossRef]
  31. Abdalla, T.A.; Koteng, D.O.; Shitote, S.M.; Matallah, M. Mechanical Properties of Eco-friendly Concrete Made with Sugarcane Bagasse Ash. Civ. Eng. J. 2022, 8, 1227–1239. [Google Scholar] [CrossRef]
  32. Ahmad, W.; Ahmad, A.; Ostrowski, K.A.; Aslam, F.; Joyklad, P.; Zajdel, P. Sustainable approach of using sugarcane bagasse ash in cement-based composites: A systematic review. Case Stud. Constr. Mater. 2021, 15, e00698. [Google Scholar] [CrossRef]
  33. Verma, M.; Dev, N. Sodium hydroxide effect on the mechanical properties of flyash-slag based geopolymer concrete. Struct. Concr. 2020, 22, E368–E379. [Google Scholar] [CrossRef]
  34. Ghafoor, M.T.; Khan, Q.S.; Qazi, A.U.; Sheikh, M.N.; Hadi, M.N.S. Influence of alkaline activators on the mechanical properties of fly ash based geopolymer concrete cured at ambient temperature. Constr. Build. Mater. 2021, 273, 121752. [Google Scholar] [CrossRef]
  35. Alghannam, M.; Albidah, A.; Abbas, H.; Al-Salloum, Y. Influence of Critical Parameters of Mix Proportions on Properties of MK-Based Geopolymer Concrete. Arab. J. Sci. Eng. 2021, 46, 4399–4408. [Google Scholar] [CrossRef]
  36. Tanu, H.M.; Unnikrishnan, S. Mechanical Strength and Microstructure of GGBS-SCBA based Geopolymer Concrete. J. Mater. Res. Technol. 2023, 24, 7816–7831. [Google Scholar] [CrossRef]
  37. Hadi, M.N.S.; Farhan, N.A.; Sheikh, M.N. Design of geopolymer concrete with GGBFS at ambient curing condition using Taguchi method. Constr. Build. Mater. 2017, 140, 424–431. [Google Scholar] [CrossRef]
  38. Aziz, I.H.; Abdullah, M.M.A.B.; Mohd Salleh, M.A.A.; Azimi, E.A.; Chaiprapa, J.; Sandu, A.V. Strength development of solely ground granulated blast furnace slag geopolymers. Constr. Build. Mater. 2020, 250, 118720. [Google Scholar] [CrossRef]
  39. Bezabih, T.; Kanali, C.; Thuo, J. Effects of teff straw ash on the mechanical and microstructural properties of ambient cured fly ash-based geopolymer mortar for onsite applications. Results Eng. 2023, 18, 101123. [Google Scholar] [CrossRef]
  40. Hanjitsuwan, S.; Hunpratub, S.; Thongbai, P.; Maensiri, S.; Sata, V.; Chindaprasirt, P. Effects of NaOH concentrations on physical and electrical properties of high calcium fly ash geopolymer paste. Cem. Concr. Compos. 2014, 45, 9–14. [Google Scholar] [CrossRef]
  41. EN 12390-3:2019; Testing Hardened Concrete—Part 3: Compressive Strength of Test Specimens. iTeh Standards: Newark, DE, USA, 2019.
  42. ASTM C496/C496M-04; Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens. iTeh Standards: Newark, DE, USA, 2004.
  43. ASTM C78-02; Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading). iTeh Standards: Newark, DE, USA, 2002.
  44. Naenudon, S.; Wongsa, A.; Ekprasert, J.; Sata, V.; Chindaprasirt, P. Enhancing the properties of fly ash-based geopolymer concrete using recycled aggregate from waste ceramic electrical insulator. J. Build. Eng. 2023, 68, 106132. [Google Scholar] [CrossRef]
  45. Rattanasak, U.; Chindaprasirt, P. Influence of NaOH solution on the synthesis of fly ash geopolymer. Miner. Eng. 2009, 22, 1073–1078. [Google Scholar] [CrossRef]
  46. Perez-Cortes, P.; Escalante-Garcia, J.I. Gel composition and molecular structure of alkali-activated metakaolin-limestone cements. Cem. Concr. Res. 2020, 137, 106211. [Google Scholar] [CrossRef]
  47. Görhan, G.; Kürklü, G. The influence of the NaOH solution on the properties of the fly ash-based geopolymer mortar cured at different temperatures. Compos. Part B Eng. 2014, 58, 371–377. [Google Scholar] [CrossRef]
  48. Elyamany, H.E.; Abd Elmoaty, A.E.M.; Elshaboury, A.M. Setting time and 7-day strength of geopolymer mortar with various binders. Constr. Build. Mater. 2018, 187, 974–983. [Google Scholar] [CrossRef]
  49. Kantarcı, F.; Türkmen, İ.; Ekinci, E. Optimization of production parameters of geopolymer mortar and concrete: A comprehensive experimental study. Constr. Build. Mater. 2019, 228, 116770. [Google Scholar] [CrossRef]
  50. Fang, G.; Ho, W.K.; Tu, W.; Zhang, M. Workability and mechanical properties of alkali-activated fly ash-slag concrete cured at ambient temperature. Constr. Build. Mater. 2018, 172, 476–487. [Google Scholar] [CrossRef]
  51. Alam, S.; Das, S.K.; Rao, B.H. Strength and durability characteristic of alkali activated GGBS stabilized red mud as geo-material. Constr. Build. Mater. 2019, 211, 932–942. [Google Scholar] [CrossRef]
  52. Reddy, M.S.; Dinakar, P.; Rao, B.H. Mix design development of fly ash and ground granulated blast furnace slag based geopolymer concrete. J. Build. Eng. 2018, 20, 712–722. [Google Scholar] [CrossRef]
  53. Pavithra, P.; Srinivasula Reddy, M.; Dinakar, P.; Hanumantha Rao, B.; Satpathy, B.K.; Mohanty, A.N. A mix design procedure for geopolymer concrete with fly ash. J. Clean. Prod. 2016, 133, 117–125. [Google Scholar] [CrossRef]
  54. Liang, X.; Ji, Y. Mechanical properties and permeability of red mud-blast furnace slag-based geopolymer concrete. SN Appl. Sci. 2021, 3, 23. [Google Scholar] [CrossRef]
  55. Muthukrishnan, S.; Ramakrishnan, S.; Sanjayan, J. Effect of alkali reactions on the rheology of one-part 3D printable geopolymer concrete. Cem. Concr. Compos. 2021, 116, 103899. [Google Scholar] [CrossRef]
  56. Zakira, U.; Zheng, K.; Xie, N.; Birgisson, B. Development of high-strength geopolymers from red mud and blast furnace slag. J. Clean. Prod. 2023, 383, 135439. [Google Scholar] [CrossRef]
  57. Bheem, P.; Somenath, M.; Bendadi, H.R. Synthesis of alkali-activated mortar using phosphogypsum-neutralised bauxite residue. Environ. Geotech. 2023; ahead of print. [Google Scholar] [CrossRef]
  58. Ranjbar, N.; Kuenzel, C.; Spangenberg, J.; Mehrali, M. Hardening evolution of geopolymers from setting to equilibrium: A review. Cem. Concr. Compos. 2020, 114, 103729. [Google Scholar] [CrossRef]
  59. Nath, P.; Sarker, P.K. Flexural strength and elastic modulus of ambient-cured blended low-calcium fly ash geopolymer concrete. Constr. Build. Mater. 2017, 130, 22–31. [Google Scholar] [CrossRef]
  60. Shilar, F.A.; Ganachari, S.V.; Patil, V.B.; Khan, T.M.Y.; Dawood Abdul Khadar, S. Molarity activity effect on mechanical and microstructure properties of geopolymer concrete: A review. Case Stud. Constr. Mater. 2022, 16, e01014. [Google Scholar] [CrossRef]
  61. Their, J.M.; Özakça, M. Developing geopolymer concrete by using cold-bonded fly ash aggregate, nano-silica, and steel fiber. Constr. Build. Mater. 2018, 180, 12–22. [Google Scholar] [CrossRef]
  62. Mousavinejad, S.H.G.; Gashti, M.F. Effects of alkaline solution/binder and Na2SiO3/NaOH ratios on fracture properties and ductility of ambient-cured GGBFS based heavyweight geopolymer concrete. Structures 2021, 32, 2118–2129. [Google Scholar] [CrossRef]
  63. Alomayri, T.; Adesina, A.; Das, S. Influence of amorphous raw rice husk ash as precursor and curing condition on the performance of alkali activated concrete. Case Stud. Constr. Mater. 2021, 15, e00777. [Google Scholar] [CrossRef]
  64. Zareei, S.A.; Ameri, F.; Bahrami, N. Microstructure, strength, and durability of eco-friendly concretes containing sugarcane bagasse ash. Constr. Build. Mater. 2018, 184, 258–268. [Google Scholar] [CrossRef]
Sustainability 16 02841 g001
Figure 1. XRD of FA and SCBA.
Figure 1. XRD of FA and SCBA.
Sustainability 16 02841 g001
Sustainability 16 02841 g002
Figure 2. SEM picture of (a) FA and (b) Processed SCBA.
Figure 2. SEM picture of (a) FA and (b) Processed SCBA.
Sustainability 16 02841 g002
Sustainability 16 02841 g003
Figure 3. Aggregates’ distribution of particle sizes.
Figure 3. Aggregates’ distribution of particle sizes.
Sustainability 16 02841 g003
Sustainability 16 02841 g004
Figure 4. Effect of NaOH molarity on FA-SCBA based GPC slump.
Figure 4. Effect of NaOH molarity on FA-SCBA based GPC slump.
Sustainability 16 02841 g004
Sustainability 16 02841 g005
Figure 5. Effect of NaOH concentration in the compressive strength of FA-SCBA based GPC.
Figure 5. Effect of NaOH concentration in the compressive strength of FA-SCBA based GPC.
Sustainability 16 02841 g005
Sustainability 16 02841 g006
Figure 6. Effect of NaOH concentration in splitting strength of FA-SCBA based GPC.
Figure 6. Effect of NaOH concentration in splitting strength of FA-SCBA based GPC.
Sustainability 16 02841 g006
Sustainability 16 02841 g007
Figure 7. Effect of NaOH concentration in flexural strength of FA-SCBA based GPC.
Figure 7. Effect of NaOH concentration in flexural strength of FA-SCBA based GPC.
Sustainability 16 02841 g007
Sustainability 16 02841 g008
Figure 8. Correlation between splitting tensile strength and compressive strength of 10 M, 12 M, 14 M, and 16 M of NaOH in GPC.
Figure 8. Correlation between splitting tensile strength and compressive strength of 10 M, 12 M, 14 M, and 16 M of NaOH in GPC.
Sustainability 16 02841 g008
Sustainability 16 02841 g009
Figure 9. Correlation between flexural strength and compressive strength of 10 M, 12 M, 14 M, and 16 M of NaOH in GPC.
Figure 9. Correlation between flexural strength and compressive strength of 10 M, 12 M, 14 M, and 16 M of NaOH in GPC.
Sustainability 16 02841 g009
Table 1. Chemical Constituents of SCBA and FA.
Table 1. Chemical Constituents of SCBA and FA.
OxidesRaw SCBAProcessed SCBAFA
SiO281.327654
Al2O35.51919.6
Fe2O36.954.26.9
CaO1.713.17.9
K2O2.683.832.2
MgO-2.76.9
P2O20.50.690.34
TiO20.650.460.88
MnO0.390.20.1
LOI10.200.971.87
Table 2. Aggregate physical properties.
Table 2. Aggregate physical properties.
AggregatesFineness ModulusSpecific GravityWater Absorption (%)Density (kg/m3)Voids Ratio (%)Crush Value (%)Impact Value (%)
Coarse agg-2.663.614684217.66.2
Fine agg2.602.613.5167728--
Table 3. Mix proportions details (Kg/m3).
Table 3. Mix proportions details (Kg/m3).
Mix IDFASCBACoarse AggFine AggAlkaline SolutionS. PNaOH M
GPC0-105000100070017512.510
GPC5-1047525100070017512.510
GPC10-1045050100070017512.510
GPC15-1042575100070017512.510
GPC20-10400100100070017512.510
GPC0-125000100070017512.512
GPC5-1247525100070017512.512
GPC10-1245050100070017512.512
GPC151242575100070017512.512
GPC20-12400100100070017512.512
GPC0-145000100070017512.514
GPC5-1447525100070017512.514
GPC10-1445050100070017512.514
GPC15-1442575100070017512.514
GPC20-14400100100070017512.514
GPC0-165000100070017512.516
GPC5-1647525100070017512.516
GPC10-1645050100070017512.516
GPC15-1642575100070017512.516
GPC20-16400100100070017512.516
Table 4. Proposed model for the relationship between the splitting tensile strength and the compressive strength.
Table 4. Proposed model for the relationship between the splitting tensile strength and the compressive strength.
Na2SiO3/NaOH 2.5
NaOH molarityEquations
10 MY = 0.04932x + 0.5269(1)
12 MY = 0.10596x − 2.3292(2)
14 MY= 0.1109x − 2.41803(3)
16 MY = 0.2013x − 8.67818(4)
Na2SiO3/NaOH 1.5
NaOH molarityEquations
10 MY = 0.08939x − 0.95248(5)
12 MY = 0.08633x − 0.43122(6)
14 MY = 0.48777x − 0.79358(7)
16 MY = 0.06926x − 0.79358(8)
When Y stands for the splitting tensile strength and x denotes the compressive strength.
Table 5. Proposed model for the relation between the splitting tensile strength and the compressive strength.
Table 5. Proposed model for the relation between the splitting tensile strength and the compressive strength.
Na2SiO3/NaOH 2.5
NaOH molarityEquations
10 MY = 0.34008x − 11.69282(9)
12 MY = 0.18108x − 2.40095(10)
14 MY = 0.18962x − 1.90198(11)
16 MY = 0.48684x − 21.86886(12)
Na2SiO3/NaOH 1.5
NaOH molarityEquations
10 MY = 0.18817x − 2.54255(13)
12 MY = 0.11587x − 1.39236(14)
14 MY = 0.67945x − 30.21794(15)
16 MY = 0.1140x − 0.47941(16)
When Y stands for the flexural strength and x denotes the compressive strength.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Rihan, M.A.M.; Alahmari, T.S.; Onchiri, R.O.; Gathimba, N.; Sabuni, B. Impact of Alkaline Concentration on the Mechanical Properties of Geopolymer Concrete Made up of Fly Ash and Sugarcane Bagasse Ash. Sustainability 2024, 16, 2841. https://doi.org/10.3390/su16072841

AMA Style

Rihan MAM, Alahmari TS, Onchiri RO, Gathimba N, Sabuni B. Impact of Alkaline Concentration on the Mechanical Properties of Geopolymer Concrete Made up of Fly Ash and Sugarcane Bagasse Ash. Sustainability. 2024; 16(7):2841. https://doi.org/10.3390/su16072841

Chicago/Turabian Style

Rihan, Mohammed Ali M., Turki S. Alahmari, Richard Ocharo Onchiri, Naftary Gathimba, and Bernadette Sabuni. 2024. "Impact of Alkaline Concentration on the Mechanical Properties of Geopolymer Concrete Made up of Fly Ash and Sugarcane Bagasse Ash" Sustainability 16, no. 7: 2841. https://doi.org/10.3390/su16072841

APA Style

Rihan, M. A. M., Alahmari, T. S., Onchiri, R. O., Gathimba, N., & Sabuni, B. (2024). Impact of Alkaline Concentration on the Mechanical Properties of Geopolymer Concrete Made up of Fly Ash and Sugarcane Bagasse Ash. Sustainability, 16(7), 2841. https://doi.org/10.3390/su16072841

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop