Mechanical properties of ambient cured fly ash‐slag‐based engineered geopolymer composites with different types of fibers

Li, Zeya; Sheikh, M. Neaz; Feng, Hu; Hadi, Muhammad N.S.

doi:10.1002/suco.202200871

Cited by 4 publications

(7 citation statements)

References 44 publications

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“…The impact of PE fibers on the compressive strength of AAP is marginal and is influenced by positive fiber bridging effects [ 67 ] and the negative air entrapping effect [ 68 ]. The stress-strain graph in Fig 6 illustrates that increasing the PE fiber content up to 1% enhances the compressive strength of AAP which can be attributed to the fiber bridging effect that improves resistance against microcrack sliding and propagation by enhancing the bonding strength between the fiber and the matrix, ultimately increasing load-carrying capacity [ 69 ]. This effect is further accentuated by ensuring good dispersion of fibers throughout the matrix.…”

Section: Resultsmentioning

confidence: 99%

“…The diminishing compressive strength with higher fiber percentages is also observed in AACs reinforced with cotton fibers [ 71 ], and a similar detrimental effect on compressive strength is noted with the incorporation of PVA fibers at volume fractions of 1.5% and 2%. Polypropylene (PP) fiber reinforced composites are not different [ 69 , 72 , 73 ].…”

Section: Resultsmentioning

confidence: 99%

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Development of innovative alkali activated paste reinforced with polyethylene fibers for concrete crack repair

Iqbal,

Ashraf,

Nazar

et al. 2024

PLoS ONE

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Concrete structures are susceptible to cracking, which can compromise their integrity and durability. Repairing them with ordinary Portland cement (OPC) paste causes shrinkage cracks to appear in the repaired surface. Alkali-activated binders offer a promising solution for repairing such cracks. This study aims to develop an alkali-activated paste (AAP) and investigate its effectiveness in repairing concrete cracks. AAPs, featuring varying percentages (0.5%, 0.75%, 1%, 1.25%, 1.5%, and 1.75%) of polyethylene (PE) fibers, are found to exhibit characteristics such as strain hardening, multiple plane cracking in tension and flexure tests, and stress-strain softening in compression tests. AAP without PE fibers experienced catastrophic failure in tension and flexure, preventing the determination of its stress-strain relationship. Notably, AAPs with 1.25% PE fibers demonstrated the highest tensile and flexural strength, exceeding that of 0.5% PE fiber reinforced AAP by 100% in tension and 70% in flexure. While 1% PE fibers resulted in the highest compressive strength, surpassing AAP without fibers by 17%. To evaluate the repair performance of AAP, OPC cubes were cast with pre-formed cracks. These cracks were induced by placing steel plates during casting and were designed to be full and half-length with widths of 1.5 mm and 3 mm. AAP both with and without PE fibers led to a substantial improvement in compressive strength, reducing the initial strength loss of 30%-50% before repair to a diminished range of 2%-20% post-repair. The impact of PE fiber content on the compressive strength of repaired OPC cube is marginal, providing more flexibility in using AAP with any fiber percentage while still achieving effective concrete crack repair. Considering economic and environmental factors, along with observed mechanical enhancements, AAPs show promising potential for widespread use in concrete repair and related applications, contributing valuable insights to the field of sustainable construction materials.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Development of innovative alkali activated paste reinforced with polyethylene fibers for concrete crack repair

Iqbal,

Ashraf,

Nazar

et al. 2024

PLoS ONE

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“…That is to say, the higher the content of sodium silicate in the blended AS solution, the more likely the AAFS binder was to undergo physical degradation, and the AAFS binders using a sodium silicate or sodium hydroxide solution more easily suffer physical degradation than those using a blend of them. The authors found that the strength of AAFS concrete, using a blended AS of NaOH and sodium silicate, decreased as the fraction of sodium silicate in the AS increased [ 37 ]. Greater strength should make AAMs less susceptible to physical degradation, such as cracking.…”

Section: Resultsmentioning

confidence: 99%

Influencing Factors of Sulfuric Acid Resistance of Ca-Rich Alkali-Activated Materials

Ikeda

2023

Materials

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In this paper, we distinguished the degradation of alkali-activated material (AAM) exposed to sulfuric acid as physical (scaling, spalling, cracking, breaking, etc.) and chemical degradation (neutralization), because the mechanisms of these two types of degradation are different. Then, the effects of curing method, raw materials, and their mixing proportions on the two kinds of degradation of AAMs containing GGBFS were investigated in detail, including liquid-filler ratio, component of alkali activator, chemical admixture, inactive filler alternative to fly ash (FA), addition of municipal waste incineration bottom ash (BA), etc. The experimental results show that (a) small liquid-filler ratio, heat-curing, and the use of blended alkali activator solution of sodium silicate and NaOH can reduce both physical and chemical degradation of AAMs; (b) large GGBFS content or AE agent addition decreases the physical degradation, but increases the chemical degradation; (c) using crushed stone powder to replace FA and adding BA or a retarder would increase the physical and chemical degradation; but (d) the use of drying shrinkage reducer composed of polyether derivatives does not affect acid resistance. We also discussed the applicability and limitation of XRD and SEM-EDS in analyzing the chemical compositions of Ca-rich AAMs exposed to sulfuric acid, and found that (e) XRD analysis can identify the gypsum formation, and the gypsum peak intensity is related to the physical degradation of the Ca-rich AAMs; (f) by SEM-EDS analysis, the decalcification and dealkalization of C-A-S-H gels can be judged from the decrease in the average Ca/Si atomic ratio and the average Na atomic percentage in the acid corrosion area, but dealumination can be only determined from the dissimilarity of Al and Si elemental maps; and (g) if the CaO/SO3 molar ratio ranges from 0.8 to 1.0, gypsum formation can be estimated.

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“…In recent years, the application of fibers in geopolymers has become more and more widespread, and many scholars have conducted in-depth studies on fibers. The incorporation of fibers has different effects on the flowability [8,9], density [10,11], shrinkage [12,13], and mechanical properties [14][15][16][17][18][19][20][21] of the geopolymer. Xu et al [14] studied the effect of two different lengths of PVA fibers on the geopolymer, and the results showed that 12 mm PVA fibers toughened the geopolymer better than 8 mm PVA fibers.…”

Section: Introductionmentioning

confidence: 99%

“…Xu et al [14] studied the effect of two different lengths of PVA fibers on the geopolymer, and the results showed that 12 mm PVA fibers toughened the geopolymer better than 8 mm PVA fibers. Li et al [16] studied the effect of low-strength polyvinyl alcohol (L-PVA) fibers, high-strength polyvinyl alcohol (H-PVA) fibers, and polyethylene (PE) fibers on geopolymer by changing the fiber type and fiber incorporation amount, and obtained the optimal incorporation amounts of 1.75%, 2.25% and 1.5% for the three; however, PE fiber was not widely used due to its high price. Khan et al [22] investigated the effect of polyethylene terephthalate (PET) fibers, PVA fibers, and PP fibers on the mechanical properties of engineered cementitious and geopolymer composites (ECC and EGC) blends, respectively.…”

Section: Introductionmentioning

confidence: 99%

Effect of Different Fibers on Shrinkage Properties and Bonding Properties of Geopolymer Mortar Repair Materials and Analysis of the Mechanism

Sui,

Li,

Zhang

et al. 2023

Coatings

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The geopolymer uses fly ash, slag, and other solid wastes as raw materials and is widely used in building repair, but it is brittle and can be made tougher by incorporating fibers. In this study, polyvinyl alcohol (PVA) fibers, polyoxymethylene (POM) fibers, and polypropylene (PP) fibers were incorporated into the geopolymer mortar repair material, and the geopolymer was tested by changing the amount of fibers incorporation as well as the type. The effect of different fibers on the geopolymer mortar repair material was analyzed by comparing the flexural strength, compressive strength, flexural toughness, shrinkage, and bonding properties with cement mortar of different samples. The geopolymer was analyzed by Diffraction of X-rays (XDR) and Scanning Electron Microscopy (SEM) to further understand the hydration products and microstructure of the geopolymer. The results showed that the incorporation of fibers reduced the flexural strength and increased the compressive strength of the geopolymer mortar repair material; the mechanical properties of the geopolymer mortar repair material decreased with the increase in fiber incorporation, and the best mechanical properties of the geopolymer mortar repair material incorporated with 1.0% PP fibers; the toughening effect of PVA fiber was best when the amount of fiber incorporated was the same; the shrinkage properties of the geopolymer were good and had little effects on the building repair; the bonding properties of repaired specimens repaired with geopolymer mortar repair materials depended on the bonding area of the fracture surface, and the bonding area was enhanced with the increase in fiber incorporation; the XRD pattern showed that the hydration products of the geopolymer were mainly CaCO3 and C–S–H gels.

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Mechanical properties of ambient cured fly ash‐slag‐based engineered geopolymer composites with different types of fibers

Cited by 4 publications

References 44 publications

Development of innovative alkali activated paste reinforced with polyethylene fibers for concrete crack repair

Development of innovative alkali activated paste reinforced with polyethylene fibers for concrete crack repair

Influencing Factors of Sulfuric Acid Resistance of Ca-Rich Alkali-Activated Materials

Effect of Different Fibers on Shrinkage Properties and Bonding Properties of Geopolymer Mortar Repair Materials and Analysis of the Mechanism

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