Effect of phosphoric acid content on the microstructure and compressive strength of phosphoric acid-based metakaolin geopolymers

Gao, Li; Zheng, Youxiong; Tang, Yan; Yu, Xingchang; Liu, Bingxin

doi:10.1016/j.heliyon.2020.e03853

Cited by 42 publications

(16 citation statements)

References 16 publications

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“…One-part mixtures usually have a much lower carbon footprint than two-part-based mixtures [ 24 ], but also often lower mechanical properties [ 25 , 26 ]. Much less often used are the other activators for geopolymer materials such as phosphate acid or lithium silicate [ 24 , 25 , 26 , 27 ].…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Fracture Properties of Long Fiber Reinforced Geopolymer Composites

et al. 2021

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The aim of the article is to analyze the structure and mechanical properties in terms of the cracking mechanics of geopolymer composites based on fly ash and river sand, as well as metakaolin and river sand with three types of reinforcement material: glass fiber, carbon fiber, and aramid fiber, in terms of their use in additive manufacturing. Geopolymer composites were reinforced with fibers in a volume ratio of 0.5%, 1.0%, and 2.0%. Subsequently, these samples were subjected to bending strength tests in accordance with the European standard EN 12390-3. The addition of fibers significantly improved the bending strength of all composites made of metakaolin and sand. The reinforcement with aramid fiber in the amount of 2.0% resulted in more than a 3-fold increase in strength compared to the reinforcement-free composites. An analysis of the morphology of the fibers was carried out on the basis of photos taken from an electron microscope. The correct addition of fibers changes the nature of the fracture from brittle to more ductile and reduces the number of cracks in the material.

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Section: Introductionmentioning

confidence: 99%

Mechanical and Fracture Properties of Long Fiber Reinforced Geopolymer Composites

et al. 2021

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“…As seen in the XRD spectra (Figure 1), the raw MK exhibited two main phases that were associated with quartz (2θ = 26.6°) (ICDD: 01-070-7344) and potassium aluminum silicate (2θ = 17.5°, 19.6°, and 20.8°) (ICDD: 00-046-0741) [29]. The AC/MK, AC/MK_Fe, PSD/MK, and PSD/MK_Fe catalysts exhibited similar XRD patterns compared to MK, and the main crystalline phase belonged to quartz, supporting the results of the elemental studies ( Table 2).…”

Section: /G) Porosity (%) --mentioning

confidence: 99%

“…MK is a highly reactive material as its surface silicon-oxygen and aluminum-oxygen structures can enhance mineralization through surface reactions [28]. Furthermore, MK, especially when treated with acid (e.g., phosphoric acid), increases the number of acidic sites and improves the strength and resistance of a material to high temperatures and to chemicals [29][30][31]. On the other hand, the mechanical strength and water stability of the material can be tailored using a crosslinking agent (e.g., boric acid) together with organic polar polymer, such as polyvinyl alcohol (PVA) [32].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Granulated Biomass Carbon Catalysts—Structure Tailoring, Characterization, and Use in Catalytic Wet Air Oxidation of Bisphenol A

et al. 2021

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New carbonized biomass–metakaolin (PSD/MK_Fe) granular composite catalyst materials were manufactured for the catalytic wet air oxidation (CWAO) of bisphenol A (BPA). These catalysts were characterized using different analytical and spectroscopic techniques, and results showed that the catalysts’ final properties were influenced by the addition of metakaolin (MK), polyvinyl alcohol, boric acid, and iron. Under the optimal CWAO experimental conditions (p: 20 bar, T: 160 °C, initial pH: 5–6, c[catalyst]: 1.0 g/L), nearly complete BPA conversion (>98%) and total organic carbon (TOC) conversion of 70% were reached. A key factor behind the enhanced catalytic activity was high specific surface area, although catalytic activity was also affected by surface acidity. These results confirmed the high efficiency of the current BPA conversion process involving the use of the easily separable and reusable PSD/MK_Fe catalyst. Therefore, biomass composite catalysts can be regarded as efficient catalysts for the oxidation of BPA during the CWAO process.

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“…In order to improve some properties, other additives are added to these binders. The most widely used additives in recent years include boric acid, which was used in the previous studies by the authors [ 9 , 10 ], and phosphoric acid and its salts [ 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

“…The addition of phosphorus-containing compounds has already been described in several publications [ 11 , 12 , 13 , 14 ]. Phosphoric acid is most often used in connection with so-called acid-based geopolymers, in which case phosphoric acid completely replaces the alkaline component of the material [ 7 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Potassium Phosphate Content in Aluminosilicate Matrix on Mechanical Properties of Carbon Prepreg Composites

et al. 2021

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Six matrices based on alkali-activated aluminosilicate with different amounts of potassium phosphate were prepared for the production of six-layer composite plates. The addition of potassium phosphate in the matrix was 2 wt%, 4 wt%, 6 wt%, 8 wt% and 10 wt% of its total weight. The matrix without the potassium phosphate was also prepared. The aim of this study was to determine whether this addition has an effect on the tensile strength or Young’s modulus of composites at temperatures up to 800 °C. Changes in the thickness and weight of the samples after this temperature were also monitored. Carbon plain weave fabric was chosen for the preparation of the composites. The results show that under normal conditions, the addition of potassium phosphate has no significant effect on the mechanical properties; the highest measured tensile strengths were around 350 MPa. However, at temperatures of 600 °C and 800 °C the addition of potassium phosphate had a positive effect, with the tensile strength of the composites being up to 300% higher than the composites without the addition. The highest measured values of composites after one hour at 600 °C were higher than 100 MPa and after 1 h at 800 °C higher than 85 MPa.

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Effect of phosphoric acid content on the microstructure and compressive strength of phosphoric acid-based metakaolin geopolymers

Cited by 42 publications

References 16 publications

Mechanical and Fracture Properties of Long Fiber Reinforced Geopolymer Composites

Mechanical and Fracture Properties of Long Fiber Reinforced Geopolymer Composites

Preparation of Granulated Biomass Carbon Catalysts—Structure Tailoring, Characterization, and Use in Catalytic Wet Air Oxidation of Bisphenol A

Effect of Potassium Phosphate Content in Aluminosilicate Matrix on Mechanical Properties of Carbon Prepreg Composites

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