Geopolymers and Geopolymer-Derived Composites

Kriven, Waltraud M.

doi:10.1016/b978-0-12-818542-1.00100-4

Cited by 21 publications

(27 citation statements)

References 52 publications

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“…2,3 In terms of mechanical performance of GP composites, there is already a large body of work that indicates them to be superior to OPC. 4,5 Aside from mechanical strength, the thermal properties of construction materials can be extremely important and a valuable tool to achieve a desired functionality.…”

Section: Introductionmentioning

confidence: 99%

“…Geopolymers (GPs) are a potential replacement for OPC concrete in construction because the manufacturing process can reduce CO 2 emissions by up to 80%, depending on raw material sourcing 2,3 . In terms of mechanical performance of GP composites, there is already a large body of work that indicates them to be superior to OPC 4,5 . Aside from mechanical strength, the thermal properties of construction materials can be extremely important and a valuable tool to achieve a desired functionality.…”

Section: Introductionmentioning

confidence: 99%

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Thermal conductivity of several geopolymer composites and discussion of their formulation

Samuel

Inumerable

Stumpf

et al. 2022

Int J Applied Ceramic Tech

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We fabricated 50.8-mm cube-shaped samples of metakaolin geopolymer (GP) composites with various additives chosen to increase or decrease the thermal conductivity of the composite. Sodium-based GP (NaGP) and GP composites were more conductive than potassium-based GP (KGP) composites for a given phase fraction of filler, but the maximum amount of filler phase was higher with KGP due to the lower viscosity of the KGP mixture. The highest thermal conductivity achieved was about 8 W/m K by KGP + 44-vol% graphite flakes, whereas NaGP + 27 vol% graphite flakes reached 4.7 W/m K. The thermal conductivity was strongly affected by the moisture remaining in the composite, which appeared to have a greater effect at higher filler content. On the other hand, the size of alumina particles (6, 40, or 120 µm) did not have any apparent effect on thermal conductivity for the same filler content. Larger particles caused less change in mixture viscosity, though, thus permitting incorporation of higher filler phase fractions and therefore higher thermal conductivity.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermal conductivity of several geopolymer composites and discussion of their formulation

Samuel

Inumerable

Stumpf

et al. 2022

Int J Applied Ceramic Tech

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“…Geopolymer processing involves the reaction of an aluminosilicate source with a highly alkaline or acidic solution, 1,4 where particle size, chemical balance, and water content are responsible for the fresh and hardened state properties 1,5 . In general, geopolymer composite compressive strengths are comparable and often superior to those of cement‐based materials, 1–5 with major advantages related to setting time and thermal performance 1,6 . Brittleness is a concerning property found for both geopolymer and cement‐based materials, 7,8 that is, poor deformation capacity.…”

Section: Introductionmentioning

confidence: 99%

“…Geopolymers are inorganic polymers manufactured under ambient temperature conditions, 1,2 resulting in a chemically‐bonded, ceramic material that requires lower energy consumption when compared to conventional ceramic sintering 3 . Geopolymer processing involves the reaction of an aluminosilicate source with a highly alkaline or acidic solution, 1,4 where particle size, chemical balance, and water content are responsible for the fresh and hardened state properties 1,5 . In general, geopolymer composite compressive strengths are comparable and often superior to those of cement‐based materials, 1–5 with major advantages related to setting time and thermal performance 1,6 .…”

Section: Introductionmentioning

confidence: 99%

V‐notched rail shear test applied to geopolymer composites

2022

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This work presents a systematic study of the shear properties of a potassiumbased geopolymer reinforced with distinct types of fibers. Chopped basalt reinforcements in lengths from 3 mm up to 50 mm and 13 μm in diameter were compared with thicker 20-mm length, basalt mini bars, sand-coated basalt mini rods, and steel fibers. The samples were tested under a V-notched rail shear tests (ASTM D7078), coupled with optical measurements, namely, digital image correlation, allowing a novel study of their crack patterns and failure modes under shear loading. In general, the use of chopped fibers resulted in shear strengths of up to 9 MPa and shear moduli of 4.3 GPa, with no significant variation with fiber length increments, neither in shear stress nor strain at peak load (0.1%). Mini bars and steel fiber reinforcements resulted in slightly lower shear stresses of 7.1 and 8.4 MPa, respectively. They exhibited greater strain values at peak loads, up to 2.1% which were attributed to fiber-matrix enhanced adhesions, thereby allowing gradual debonding and increased ductility. This effect was also recorded for mini rods, but at much lower strength levels, which did not contribute to their multiple cracking capacities. The alignment of the mini rods in 45 • directions resulted in a 50% increase in shear stress, showing the feasibility of tailoring the manufacturing process to attend to distinct demands.

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“…Geopolymer refers to a large group of nanoporous, nanoparticulate materials that are synthesized by dissolution and polycondensation of aluminosilicates in basic solutions and can be made from a variety of starting materials, such as industrial waste ash, volcanic rock, or calcined clay. [1][2][3][4][5][6][7][8][9] Geopolymers are a castable refractory, meaning complex molds and shapes can be filled and cured at room temperature in as little as 24 h and subsequently used at high temperature. 10 Geopolymers are X-ray amorphous, corrosion resistant, refractory, and made at ambient temperature and pressure in a manner similar to cements.…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution of amorphous self‐healing geopolymer composites containing alumina and glass frit

Keane

Jacob

Belusko³

et al. 2022

Int J Ceramic Engine & Sci

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Geopolymer refers to a large group of nanoporous, nanoparticulate materials that are synthesized by dissolution and polycondensation of aluminosilicates in basic solutions and can be made from a variety of starting materials, such as industrial waste ash, volcanic rock, or calcined clay. Geopolymers are X-ray amorphous, corrosion resistant, refractory, and made at ambient temperature and pressure similar to cements. In this study, potassium metakaolin-based geopolymer (KGP) composites containing alumina platelets and glass frit were fabricated, and the impact of heating temperature, dwell time, and heating/cooling rate on the microstructure was studied. The composites, heat treated up to 900 • C for up to 20 h using heating/cooling rates of up to 1 • C/min, showed that the addition of alumina platelets prevented major microcracking and was also able to reduce linear shrinkage. Glass frit has been shown to heal microcracks formed during KGP dehydration and crystallization. The resulting material had an open porosity of less than 1% and a uniform surface glaze of 250 μm thickness, while Oswald ripening of round closed pores occurred due to the migration of molten glass in the system.

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Geopolymers and Geopolymer-Derived Composites

Cited by 21 publications

References 52 publications

Thermal conductivity of several geopolymer composites and discussion of their formulation

Thermal conductivity of several geopolymer composites and discussion of their formulation

V‐notched rail shear test applied to geopolymer composites

Microstructural evolution of amorphous self‐healing geopolymer composites containing alumina and glass frit

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