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Francisca Puertas

Bio: Francisca Puertas is an academic researcher from Spanish National Research Council. The author has contributed to research in topics: Portland cement & Cement. The author has an hindex of 45, co-authored 190 publications receiving 8913 citations.


Papers
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TL;DR: The activation of fly ash/slag pastes with NaOH solutions has been studied in this paper, where the authors established the equations of the models describing the mechanical behaviour of these pastes as a function of the factors and levels considered.

745 citations

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TL;DR: In this article, an experimental and computational study has been conducted to define a structural model for the C-A-S-H gel forming in alkali-activated slag (AAS) pastes that would account for the mechanical properties of these materials.
Abstract: For first time, an experimental and computational study has been conducted to define a structural model for the C-A-S-H gel forming in alkali-activated slag (AAS) pastes that would account for the mechanical properties of these materials. The study involved a comparison with the C-S-H gel forming in a Portland cement paste. The structure of the C-A-S-H gels in AAS pastes depends on the nature of the alkali activator. When the activator is a NaOH, the structure of the C-S-H gel falls in between tobermorite 1.4 nm with a mean chain length of five, and tobermorite 1.1 nm with a mean length of 14. When waterglass is the activator the structure of the C-A-S-H gel is indicative of the co-existence of tobermorite 1.4 nm with a chain length of 11 and tobermorite 1.1 nm with a chain length of 14. This very densely packed structure gives rise to excellent mechanical properties.

547 citations

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TL;DR: In this paper, the joint influence of a series of factors (specific surface of slag, curing temperature, activator concentration, and the nature of the alkaline activator) on the development of mechanical strengths in alkaline-activated slag cement mortars was investigated.

520 citations

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TL;DR: In this article, the results of a research project initiated to study the stability of these materials when exposed to aggressive solutions were presented, where prisms of mortar made of sand and alkali-activated metakaolin were immersed in deionized water, ASTM sea water, sodium sulfate solution (4.4% wt), and sulfuric acid solution (0.001 M).

510 citations

Journal ArticleDOI
TL;DR: A mechanical, mineralogical and microstructural characterisation of the cement pastes obtained by alkaline activation of fly ash/slag mixtures cured at different temperatures has been carried out in this article.
Abstract: A mechanical, mineralogical and microstructural characterisation of the cement pastes obtained by alkaline activation of fly ash/slag mixtures cured at different temperatures has been carried out. The pastes obtained were characterised by XRD, FTIR, MAS NMR, SEM/EDX, atomic absorption and ion chromatography, also the insoluble residue in HCl was determined. The results obtained have proved the existence of two different reaction products in those activated pastes. The average atomic ratios in the main reaction product were Ca/Si∼0.8, Al/Ca∼0.6, Si/Al∼2–3. Such analysis corresponds to calcium silicate hydrate rich in Al, which includes Na in its structure. Other reaction product which was detected in the pastes as result of fly ash activation, was an alkaline aluminosilicate hydrate with a three-dimensional structure.

375 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the mechanism of activation of fly ash with highly alkaline solutions is described, and the product of the reaction is an amorphous aluminosilicate gel having a structure similar to that of zeolitic precursors.

1,779 citations

Journal ArticleDOI
TL;DR: In this paper, the potential position of and drivers for inorganic polymers (“geopolymers”) as an element of the push for a sustainable concrete industry are discussed.

1,444 citations

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TL;DR: In this paper, a mechanistic model accounting for reduced structural reorganization and densification in the microstructure of geopolymer gels with high concentrations of soluble silicon in the activating solution has been proposed.

1,309 citations

Journal ArticleDOI
TL;DR: In this paper, four promising alternative binders available as alternatives to Portland cement are discussed, namely calcium aluminate cement, calcium sulfoaluminate cements, alkali-activated binders, and supersulfated cements.

1,237 citations

Journal ArticleDOI
TL;DR: Aluminosilicate-based alkaline cements have been classified into five categories as discussed by the authors, and the key advances made in the understanding of synthetic gels are discussed, which ultimately finds hybrid cements to be technologically viable materials for contemporary construction.

1,104 citations