Effect of mixed fibers on fly ash-based geopolymer resistance against carbonation

Li, Faping; Chen, Defeng; Yang, Zheming; Lu, Yiyan; Zhang, Haojun; Li, Shan

doi:10.1016/j.conbuildmat.2022.126394

Cited by 30 publications

(11 citation statements)

References 40 publications

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“…Murthy's study shows that 1% is the best content for polypropylene fiber to improve the compressive strength of geopolymer, 41 while Bellum's research indicates that 2% is the best content for polypropylene fiber to improve the compressive strength of geopolymer, 16 and Wang's study considers 0.8% polyvinyl alcohol fiber the best dosage to improve the compressive strength of geopolymer. However, Wang and Li's study indicates that a higher polypropylene fiber content represents a higher compressive strength 2143 . Xu has found that the optimal dosage of basalt fiber to improve the compressive strength of geopolymer is 0.6%, and that the comprehensive performance of 6 mm basalt fiber is better than that of 3 mm basalt fiber 44 .…”

Section: Mechanical Properties Of Fiber Reinforced Geopolymersmentioning

confidence: 99%

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Mechanical properties and durability of fiber reinforced geopolymer composites: A review on recent progress

Qin,

Yan,

Zhou

et al. 2023

Engineering Reports

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Geopolymer concrete has similar mechanical properties to ordinary Portland cement (OPC) concrete, and even better properties in high temperature, high corrosion environment. However, geopolymer still has the disadvantages of large shrinkage and high brittleness, which greatly limit its application. Fiber reinforcement is widely used in various geopolymer systems to overcome the brittleness issue, but still retains the high strength. Over the past 10 years, great progress has been made in the research of fiber reinforced geopolymers in the aspect of toughening efficiency and durability improvement. Many studies have been conducted on fiber reinforced geopolymers, but there are still few systematic summaries on the addition of inorganic fibers and organic fibers to geopolymers. What is more there are many novel studies such as the application of geopolymers to 3D printing and the new concept of fiber factor have not been reviewed. In this paper, inorganic fibers, natural fibers and synthetic fibers in geopolymers are briefly reviewed, and their specific effects on geopolymers' compressive, flexural, tensile strength, fracture toughness, shear strength and durability such as shrinkage, chemical resistance, freeze–thaw resistance are reviewed. The current understanding of bonding mechanism and fiber‐geopolymer interface are also discussed, and related knowledge gaps and future work challenges are correspondingly pointed out.

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Section: Mechanical Properties Of Fiber Reinforced Geopolymersmentioning

confidence: 99%

“…Effect of fiber content on the compressive strength of geopolymer 15–17,21,24,26,31,39–47 . Reproduced with permission 15–17,21,24,26,31,39–47 . Elsevier 2023.…”

Section: Mechanical Properties Of Fiber Reinforced Geopolymersmentioning

confidence: 99%

Mechanical properties and durability of fiber reinforced geopolymer composites: A review on recent progress

Qin,

Yan,

Zhou

et al. 2023

Engineering Reports

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“…While GPs can be synthesized with no Ca in the system, such GPs require curing at elevated temperatures of at least 50 °C. This restricts their practical application in the field of civil engineering but not necessarily in wellbore construction. , In GP systems based on precursors that do not contain Ca, Ca is commonly incorporated as an additive to eliminate this need for elevated curing temperatures, for example, through the addition of OPC, GGBFS, class C fly ash, calcium hydroxide, calcium carbonates, calcium aluminate cement, or natural calcium silicate materials. ,,,− In fact, many argue that the coexistence of N–A–S–H and C(−A)–S–H gels leads to the reduced porosity/permeability, reduced water adsorption, increased density, stronger networks benefiting from composite binding phases, and higher compressive strengths of the GP system. ,,,, For instance, the positive impacts that Ca can have on GP gel structures is demonstrated by Yang et al, who reported the presence of amorphous homogeneous N–C(−A)–S–H in fly-ash-based GPs modified with slags, where calcium contributes to the formation of a more compact microstructure and consequently higher compressive strengths compared to unmodified fly-ash-based GPs. , …”

Section: Factors Affecting the Properties Of Gpsmentioning

confidence: 99%

“…In GP systems, however, carbonation mechanisms are different, as the main sources of alkalinity are the activator solutions used, based mainly on NaOH and KOH. A reaction of these components with CO 2 produces Na 2 CO 3 and K 2 CO 3 , which can induce a carbonate–bicarbonate phase equilibrium and reduce the alkalinity of the system (to pH values around 10–10.5). ,,,,,, Due to the presence of free alkalis and the high reactivity of these unreacted species, GPs are also prone to carbonation; however, some studies have demonstrated a much lower impact of carbonation on GP properties compared to OPC. ,,,,,,,, This might be due to the fact that, in OPC, both C(−A)–S–H and portlandite can be carbonated, while in GP systems, C(−A)–S–H gel (if present) is the phase that can be directly carbonated …”

Section: Factors Affecting the Properties Of Gpsmentioning

confidence: 99%

“…When considering carbonation as a purely deleterious effect, the dissolution and ingress of CO 2 into the pore solution lead to reduced pore-fluid pH and degradation of the cementitious material . In accelerated carbonation experiments, such as are commonly used to explore the degrees and mechanisms of carbonation, a lower resistance to carbonation is frequently recorded for AAMs compared to OPCs. , However, such results are not necessarily applicable, as bicarbonate formation and the subsequent phase equilibrium alterations occurring at the high CO 2 concentrations imposed in these tests can lead to higher pH reductions compared to natural carbonation. ,, Hence, the more appropriate method to assess the carbonation-induced durability damage of GPs is to measure the natural carbonation depth of materials at a more realistic CO 2 content.…”

Section: Factors Affecting the Properties Of Gpsmentioning

confidence: 99%

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Review on Geopolymers as Wellbore Sealants: State of the Art Optimization for CO₂ Exposure and Perspectives

et al. 2023

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Wellbores used in underground production and storage activities, including carbon capture and storage (CCS), are typically sealed using sealants based on Ordinary Portland Cement (OPC). However, leakage along these seals or through them during CCS operations can pose a significant threat to long-term storage integrity. In this review paper, we explore the potential of geopolymer (GP) systems as alternative sealants in wells exposed to CO 2 during CCS. First, we discuss how key parameters control the mechanical properties, permeability, and chemical durability of GPs based on different starting materials as well as their optimum values. These parameters include the chemical and mineralogical composition, particle size, and particle shape of the precursor materials; the composition of the hardener; the chemistry of the full system (particularly the Si/Al, Si/(Na+K), Si/Ca, Si/Mg, and Si/Fe ratios); the water content of the mix; and the conditions under which curing occurs. Next, we review existing knowledge on the use of GPs as wellbore sealants to identify key knowledge gaps and challenges and the research needed to address these challenges. Our review shows the great potential of GPs as alternative wellbore sealant materials in CCS (as well as other applications) due to their high corrosion durability, low matrix permeability, and good mechanical properties. However, important challenges are identified that require further research, such as mix optimization, taking into account curing and exposure conditions and available starting materials; the development of optimalization workflows, along with building larger data sets on how the identified parameters affect GP properties, can streamline this optimization for future applications.

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Comprehensive Review of Fly Ash: Environmental Impact and Applications

Sharma,

Dash,

Gupta

2024

Environmental Quality Mgmt

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Fly ash (FyA), a byproduct from coal combustion in power plants, has become increasingly valuable due to its pozzolanic properties. Primarily, FyA finds applications in the construction industry, including road and brick construction, forest road building, and the cement industry. When added to concrete, it enhances splitting tensile strength, compressive strength, and workability, while also reducing the environmental impact of cement production. Beyond construction, FyA is utilized for air pollutant removal and serves as an adsorbent for various contaminants. It also plays a role in creating geopolymers and nanocomposites, promoting the development of eco‐friendly construction materials. This review article presents current data on thermal power plants (ThPPs) in India, the challenges in FyA management, and its environmental impact. It also discusses relevant Indian policies and highlights ongoing research aimed at improving the efficiency and expanding the applications of FyA in various industrial sectors, such as battery manufacturing, zeolite synthesis, and cenosphere extraction. These efforts underscore FyA's potential in supporting sustainable practices. The findings of this review address critical issues related to FyA. By reducing the environmental footprint of cement manufacturing, removing air pollutants, and acting as an adsorbent for various contaminants, FyA demonstrates significant potential in pollution mitigation. It also contributes to the development of eco‐friendly construction materials and promotes sustainability in the construction sector. Effective management practices are essential to minimize FyA's negative impact on human health and the environment. The article emphasizes the need for greater awareness and implementation of policies to address these issues comprehensively. By providing a detailed understanding of the benefits and challenges associated with FyA, it aims to pave the way for more effective and sustainable utilization of this industrial byproduct.

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Effect of mixed fibers on fly ash-based geopolymer resistance against carbonation

Cited by 30 publications

References 40 publications

Mechanical properties and durability of fiber reinforced geopolymer composites: A review on recent progress

Mechanical properties and durability of fiber reinforced geopolymer composites: A review on recent progress

Review on Geopolymers as Wellbore Sealants: State of the Art Optimization for CO₂ Exposure and Perspectives

Comprehensive Review of Fly Ash: Environmental Impact and Applications

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Effect of mixed fibers on fly ash-based geopolymer resistance against carbonation

Cited by 30 publications

References 40 publications

Mechanical properties and durability of fiber reinforced geopolymer composites: A review on recent progress

Mechanical properties and durability of fiber reinforced geopolymer composites: A review on recent progress

Review on Geopolymers as Wellbore Sealants: State of the Art Optimization for CO2 Exposure and Perspectives

Comprehensive Review of Fly Ash: Environmental Impact and Applications

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Product

Resources

About

Review on Geopolymers as Wellbore Sealants: State of the Art Optimization for CO₂ Exposure and Perspectives