Polyphosphate-modified calcium aluminate cement under normal and elevated temperatures: Phase evolution, microstructure, and mechanical properties

Xu, Weiting; Dai, Jian‐Guo; Ding, Zhu; Wang, Yanshuai

doi:10.1016/j.ceramint.2017.08.102

Cited by 30 publications

(9 citation statements)

References 25 publications

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“…Fresh CPC is a castable paste which is preferable for bone defects reconstruction with minimum invasive surgery since it can be resorbed under physiological conditions after embedding into the body (Xue et al, 2012;Inzana et al, 2014;Xu et al, 2017). Thus, the moldable properties of calcium-blended SAP geopolymer extend its applications to 3D printing for building arts in civil engineering or other aesthetic fields.…”

Section: Effect Of "Impurities" In Sap Geopolymermentioning

confidence: 99%

Silico-Aluminophosphate and Alkali-Aluminosilicate Geopolymers: A Comparative Review

2019

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Chemically activated materials (often termed as geopolymer) have received attracting attentions in civil, material and environmental research fields as a toolkit alternative to traditional Portland cement in specific applications. This paper presents a comparative review on silico-aluminophosphate (SAP) geopolymers in terms of definition, chemistries involved during geopolymerization, mechanical performance, durability, environmental impacts, and their potentials in applications relative to conventional alkali-aluminosilicate (AAS) geopolymers. Recommendations for future applications are also highlighted. It is found that S-A-P gels with six-coordinated aluminum environment dominate in SAP geopolymers, while the aluminum in N-A-S-H gels formed in the AAS geopolymers is characterized by four-coordinated features. Besides, the slow performance development of SAP geopolymer matrix under ambient temperature curing can be compensated through incorporating additional countermeasures (e.g., metal sources) which allow the tailored design of such geopolymers for certain in-situ applications. Generally, the calcium-bearing C-(A)-S-H gels co-existing with N-A-S-H gels are dominant in AAS geopolymers, while the S-A-P gels enhanced by phosphate-containing crystalline/amorphous phases are the main products in SAP geopolymers. The SAP geopolymers show their environmental friendliness relative to the AAS geopolymers due to the utilization of phosphate activators that require lower production energy relative to silicate-containing activators. However, the higher cost of phosphate activators may confine the applications of SAP geopolymers in some exquisite or special fields.

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Section: Effect Of "Impurities" In Sap Geopolymermentioning

confidence: 99%

Silico-Aluminophosphate and Alkali-Aluminosilicate Geopolymers: A Comparative Review

2019

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“…The Gd–Eu couple is well known for its efficient conversion of the absorbed high-energy photons into two visible ones [20–24]. This phenomenon may be followed by a sequence of two steps of energies transfer.…”

Section: Introductionmentioning

confidence: 99%

Structural Study of Europium Doped Gadolinium Polyphosphates LiGd(PO₃)₄ and Its Effect on Their Spectroscopic, Thermal, Magnetic, and Optical Properties

Hammami

Boudjada

Megriche

2018

International Journal of Analytical Chemistry

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Alkali metal-rare earth polyphosphates LiGd(1-x)Eux(PO3)4 (LGP:Eu3+) (where x= 0, 0.02 and 0.04) were synthesized by solid-state reaction. The Rietveld refinement showed the following cell parameters: I 2/a space group, a=9.635(3) Å, b=7.035(3) Å, c=13.191(3) Å, β=90.082°, V= 894.214Å3, and Z=4. The similarity between RF=4.21% and RB=4.31% indicated that the realized refinement is reliable. The crystal structure consists of infinite zig-zag chains of (PO4)3- tetrahedra, linked by bridging oxygen. The acyclic structure of polyphosphates is confirmed by infrared and Raman (IR) spectroscopies. A good thermal stability up to 940°C and paramagnetic behavior of these compounds were also proved by thermal analyses and magnetic susceptibility measurements, respectively. Excitation spectra revealed the charge transfer phenomenon between O2- and Eu3+ (CTB), the energy transfer from Gd3+ to Eu3+, and the intrinsic 4f-4f transitions of Eu3+ where the electronic transitions were also identified. Moreover, LGP:Eu3+ can emit intense reddish orange light under excitation at 394 nm. The strongest tow at 578 and 601 nm can be attributed to the transitions from excited state 5D0 to ground states 7F1 and 7F2, respectively.

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“…One of the reasons why the interest in the development of geopolymers activated with acid solutions based on potassium is increasing, is the superior compressive strength of the resulting materials, compared to those which are alkaline-activated [ 17 ]. Moreover, the economic aspects also tip the scales in favour of the acid-activated ones, this aspect is due to the fact that the sodium hydroxide solutions do not present a sufficiently high geopolymerization potential when used alone.…”

Section: Introductionmentioning

confidence: 99%

XRD and TG-DTA Study of New Phosphate-Based Geopolymers with Coal Ash or Metakaolin as Aluminosilicate Source and Mine Tailings Addition

et al. 2021

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Coal ash-based geopolymers with mine tailings addition activated with phosphate acid were synthesized for the first time at room temperature. In addition, three types of aluminosilicate sources were used as single raw materials or in a 1/1 wt. ratio to obtain five types of geopolymers activated with H3PO4. The thermal behaviour of the obtained geopolymers was studied between room temperature and 600 °C by Thermogravimetry-Differential Thermal Analysis (TG-DTA) and the phase composition after 28 days of curing at room temperature was analysed by X-ray diffraction (XRD). During heating, the acid-activated geopolymers exhibited similar behaviour to alkali-activated geopolymers. All of the samples showed endothermic peaks up to 300 °C due to water evaporation, while the samples with mine tailings showed two significant exothermic peaks above 400 °C due to oxidation reactions. The phase analysis confirmed the dissolution of the aluminosilicate sources in the presence of H3PO4 by significant changes in the XRD patterns of the raw materials and by the broadening of the peaks because of typically amorphous silicophosphate (Si–P), aluminophosphate (Al–P) or silico-alumino-phosphate (Si–Al–P) formation. The phases resulted from geopolymerisation are berlinite (AlPO4), brushite (CaHPO4∙2H2O), anhydrite (CaSO4) or ettringite as AFt and AFm phases.

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Polyphosphate-modified calcium aluminate cement under normal and elevated temperatures: Phase evolution, microstructure, and mechanical properties

Cited by 30 publications

References 25 publications

Silico-Aluminophosphate and Alkali-Aluminosilicate Geopolymers: A Comparative Review

Silico-Aluminophosphate and Alkali-Aluminosilicate Geopolymers: A Comparative Review

Structural Study of Europium Doped Gadolinium Polyphosphates LiGd(PO₃)₄ and Its Effect on Their Spectroscopic, Thermal, Magnetic, and Optical Properties

XRD and TG-DTA Study of New Phosphate-Based Geopolymers with Coal Ash or Metakaolin as Aluminosilicate Source and Mine Tailings Addition

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Polyphosphate-modified calcium aluminate cement under normal and elevated temperatures: Phase evolution, microstructure, and mechanical properties

Cited by 30 publications

References 25 publications

Silico-Aluminophosphate and Alkali-Aluminosilicate Geopolymers: A Comparative Review

Silico-Aluminophosphate and Alkali-Aluminosilicate Geopolymers: A Comparative Review

Structural Study of Europium Doped Gadolinium Polyphosphates LiGd(PO3)4 and Its Effect on Their Spectroscopic, Thermal, Magnetic, and Optical Properties

XRD and TG-DTA Study of New Phosphate-Based Geopolymers with Coal Ash or Metakaolin as Aluminosilicate Source and Mine Tailings Addition

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Structural Study of Europium Doped Gadolinium Polyphosphates LiGd(PO₃)₄ and Its Effect on Their Spectroscopic, Thermal, Magnetic, and Optical Properties