Fundamental study on chemical stability of phosphoaluminate cement hardened pastes

Li, S.; Yi, Zhihua; Wang, W.; Zhao, Feng Qing; Liu, B.; Hu, Jun

doi:10.1179/143307507x196590

Cited by 15 publications

(8 citation statements)

References 6 publications

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“…The short setting time was in line with data reported by Swift et al (2013b). However, on the mechanical strength, data from literature show higher values: in general, the polyphosphate-modified mortars attained compressive strengths in the range from 90 to 100 MPa after 28 curing days (Swift et al 2013b, Li et al, 2007. Differences could arise from the different chemical composition of the raw CAC, since in the present work an iron-rich CAC cement (17 wt.% of Fe 2 O 3 , similar to Ciment Fondu) was used, instead of an iron-lean CAC employed in the papers quoted (< 2wt.% Fe 2 O 3 ).…”

Section: Setting Time Mechanical Performance and Microstructural Anasupporting

confidence: 78%

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Treatment of toxic metal aqueous solutions: Encapsulation in a phosphate-calcium aluminate matrix

Fernández

Navarro-Blasco

Durán

et al. 2014

Journal of Environmental Management

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Polyphosphate-modified calcium aluminate cement matrices were prepared by using aqueous solutions polluted with toxic metals as mixing water to obtain wastecontaining solid blocks with improved management and disposal. Synthetically contaminated waters containing either Pb or Cu or Zn were incorporated into phosphoaluminate cement mortars and the effects of the metal's presence on setting time and mechanical performance were assessed. Sorption and leaching tests were also executed and both retention and release patterns were investigated. For all three metals, high uptake capacities as well as percentages of retention larger than 99.9% were measured. Both Pb and Cu were seen to be largely compatible with this cementitious matrix, rendering the obtained blocks suitable for landfilling or for building purposes. However, Zn spoilt the compressive strength values because of its reaction with hydrogen phosphate anions, hindering the development of the binding matrix.

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Section: Setting Time Mechanical Performance and Microstructural Anasupporting

confidence: 78%

“…S5, in Supplementary materials). According to the reported data (Li et al, 2007;Sugama et al, 1999) and to our experimental measures, the pH of a phosphoaluminate cement matrix usually ranges from 6 to 10.5 (i.e. from slightly acidic to mild alkaline media, depending on the extent of the acid-base reaction).…”

Section: Metal-binder Interactionmentioning

confidence: 99%

Treatment of toxic metal aqueous solutions: Encapsulation in a phosphate-calcium aluminate matrix

Fernández

Navarro-Blasco

Durán

et al. 2014

Journal of Environmental Management

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“…As the figure shows, the main phases identified in specimen A (0% In specimens B to E, with Fe 2 O 3 ranging from 10 to 13%, the main phases were CA 1-Y (P Y ) and CP 1-z (A z ). In these patterns, the LHss signal was more intense than on the pattern for specimen A, while the line for C 12 Figure 2. Al, P and Ca overlapped in the regularly shaped α particles, which consequently consisted of calcium phosphoaluminate or modified monocalcium aluminate.…”

Section: Variation In Phase Compositionmentioning

confidence: 99%

“…PALC is characterised by high early age and increasing long-term strength. Its low alkalinity affords it long durability, its low porosity, high resistance to frost and penetration, and the absence of Ca(OH) 2 in its hydraulic system, resistance to carbonation (12).…”

Section: Introductionmentioning

confidence: 99%

Constituent phases and mechanical properties of iron oxide-additioned phosphoaluminate cement

et al. 2015

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Iron oxide was added to phosphoaluminate clinker and its effects on cement constituents were determined using XRD, DSC, SEM-EDS and conduction calorimetry analysis. The variations in compressive strength were also studied. The results showed that in moderate amounts, iron oxide acts as a mineraliser during clinker sintering, furthering the conversion of CA 1-Y (P Y ) to LHss at a lower temperature than normally required for that reaction. The main constituents of iron oxide-rich phosphoaluminate clinker included LHss, CA 1-Y (P Y ), CP 1-Z (A Z ) and ferrite. The EDS findings showed that the composition of the ferrite phase was nonuniform. The conclusion drawn was that by modifying the dose of Fe 2 O 3 , the composition of phosphoaluminate cement can be controlled to produce clinker and cement compliant with different mechanical strength requirements. The conduction calorimetry findings were consistent with those results. RESUMEN: Fases constituyentes y propiedades mecánicas de un cemento de fosfoaluminato con adición de óxido de hierro.Este trabajo estudia, mediante DRX DSC, SEM-EDS y calorimetría de conducción, el efecto de la adición de óxido de hierro a un clinker de fosfoaluminato, así como las variaciones sufridas en su resistencia a compresión. Los resultados mostraron que en cantidades moderadas, el óxido de hierro actúa como mineralizador durante la sinterización del clinker, promoviendo la conversión de CA 1-Y (P Y ) a LHss a una temperatura más baja de la normalmente requerida. Los componentes principales del clínker de fosfoaluminato con óxido de hierrop son LHss, CA 1-Y (P Y ), CP 1-Z (A Z ) y fase ferritica. Los resultados de EDS mostraron que la composición de esta fase ferrítica no era uniforme. DE este estudio se ha podido concluir que variando la dosificación del Fe 2 O 3 , se puede controlar la composición del fosfoaluminato para producir clinker y cemento compatibles con diferentes requisitos de resistencia mecánica. Los resultados de calorimetría de conducción fueron consistentes con los resultados.

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“…(solid solution of calcium phosphoaluminate), CA S.S. , C 2 AS, C X P and a certain amount of amorphous phase, has been developed. The hydrates of PALC are Hydrated calcium phosphoaluminate gel (C-A-P (Si)-H, C-A-P-H), hydrated calcium phosphate gel (C-P-H) and their corresponding hydration crystals [8] . In this paper, the mechanical properties and the microstructure of the PALC with and without SF/NS at different ages will be discussed in detail.…”

Section: Introductionmentioning

confidence: 99%

Influence of Silica Fume/Nanosilica on the Strength and Microstructure of Phosphoaluminate Cement

Ren

Tian

2011

AMR

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The influence of Silica fume/Nanosilica on the Performance of phosphoaluminate cement was studied in the paper. The microstructure and morphology was determined by X-ray diffraction and scanning electron microscopy. The experimental results show that the phosphoaluminate cement with 4% of added Silica fume/Nanosilica(1:1) by weight of cement has an optimum splitting strength, in which the increase of splitting strength are about 15.1%,11.8% and 24.6% at 3days,7days and 28 days. The reason for causing the above results are the hydration rate and the amount of the hydrates of PALC with 4% Silica fume/Nanosilica have been increased significantly at different hydration time because of the role played by Silica fume and Nanosilica together.

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Fundamental study on chemical stability of phosphoaluminate cement hardened pastes

Cited by 15 publications

References 6 publications

Treatment of toxic metal aqueous solutions: Encapsulation in a phosphate-calcium aluminate matrix

Treatment of toxic metal aqueous solutions: Encapsulation in a phosphate-calcium aluminate matrix

Constituent phases and mechanical properties of iron oxide-additioned phosphoaluminate cement

Influence of Silica Fume/Nanosilica on the Strength and Microstructure of Phosphoaluminate Cement

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