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The spectroscopy technique of Micro-Raman is an appropriate method to investigate the microscopic structure of internally heterogeneous (i.e., composed of multiple layers) agro-food products. The effects of applying magnetic fields (magneto-priming technique) and imbibition on the chemical makeup of Triticale seed were studied, particularly in its pericarp, germ and endosperm parts, with the help of Micro-Raman. In light of the results obtained, the magneto-primed seeds soaked in water presented a greater number of chemical compounds than the control seeds, although those treatments were not as effective as the ones with only magneto-priming. The effects of the magneto-priming treatment were especially noticeable in the endosperm due to the large number of chemical compounds identified. The seed composition differences among treatments showed that the use of Micro-Raman jointly with magneto-priming is an appropriate method to obtain and analyse information of the key components of Triticale seeds, notably regarding their pericarp and endosperm.
Jose Alvarez; Sagrario Martinez-Ramirez; Elvira Martinez. Magneto-Primed Triticale Seeds Studied by Micro-Raman Spectra. Plants 2021, 10, 1083 .
AMA StyleJose Alvarez, Sagrario Martinez-Ramirez, Elvira Martinez. Magneto-Primed Triticale Seeds Studied by Micro-Raman Spectra. Plants. 2021; 10 (6):1083.
Chicago/Turabian StyleJose Alvarez; Sagrario Martinez-Ramirez; Elvira Martinez. 2021. "Magneto-Primed Triticale Seeds Studied by Micro-Raman Spectra." Plants 10, no. 6: 1083.
This work analyses the influence of fine concrete fractions (<5 mm) of different natures —calcareous (HcG) and siliceous (HsT)—obtained from construction and demolition waste (C&DW) on the behaviour of blended cement pastes with partial replacements between 5 and 10%. The two C&DW fractions were characterised by different instrumental techniques. Subsequently, their lime-fixing capacity and the physico-mechanical properties of the blended cement pastes were analysed. Lastly, the environmental benefits of reusing these fine wastes in the manufacture of future eco-efficient cement pastes were examined. The results show that HsT and HcG exhibit weak pozzolanic activity, owing to their low reactive silica and alumina content. Despite this, the new cement pastes meet the physical and mechanical requirements of the existing regulations for common cements. It should be highlighted that the blended cement pastes initially showed a coarser pore network, but then they underwent a refinement process between 2 and 28 days, along with a gain in compressive strength, possibly due to the double pozzolanic and filler effect of the wastes. The environmental viability of the blended cements was evaluated in a Life Cycle Assessment (LCA) concluding that the overall environmental impact could be reduced in the same proportion of the replacement rate. This is in line with the Circular Economy goals and the 2030 Agenda for Sustainable Development.
Laura Caneda-Martínez; Manuel Monasterio; Jaime Moreno-Juez; Sagrario Martínez-Ramírez; Rosario García; Moisés Frías. Behaviour and Properties of Eco-Cement Pastes Elaborated with Recycled Concrete Powder from Construction and Demolition Wastes. Materials 2021, 14, 1299 .
AMA StyleLaura Caneda-Martínez, Manuel Monasterio, Jaime Moreno-Juez, Sagrario Martínez-Ramírez, Rosario García, Moisés Frías. Behaviour and Properties of Eco-Cement Pastes Elaborated with Recycled Concrete Powder from Construction and Demolition Wastes. Materials. 2021; 14 (5):1299.
Chicago/Turabian StyleLaura Caneda-Martínez; Manuel Monasterio; Jaime Moreno-Juez; Sagrario Martínez-Ramírez; Rosario García; Moisés Frías. 2021. "Behaviour and Properties of Eco-Cement Pastes Elaborated with Recycled Concrete Powder from Construction and Demolition Wastes." Materials 14, no. 5: 1299.
The main objective of RILEM TC LHS-277 “Specifications for testing and evaluation of lime-based repair materials for historic Structures” is the revision, adaption and, when necessary proposal, of the test methods to accurately study lime-based binding systems and mixtures, such as mortars and grouts. The empiric use of the lime-based composites and the predominant employ of cement in the field of Civil Engineering have led to the widespread application of test methods developed for cement-based composites to test the former. However, the clear differences in composition and performance between modern cement binders and lime-based materials would advise to explore specific test methods for the latter. To undertake this task the previous knowledge on the mechanisms of setting and hardening of these binders must be revised, arranged and synthesized. Processes such as drying, carbonation, hydration and pozzolanic reaction may occur during the setting and hardening of lime-based mortars and competition between them cannot be underestimated. With the aim of underpinning the revision and proposal of test methods for lime-based systems, this review paper reports a comprehensive study of the mechanisms of setting and hardening of these binders, considering the variability of the composition, which includes pure air lime as well as lime with hydraulic properties, lime-cement and lime-pozzolan systems.
J. I. Alvarez; R. Veiga; S. Martínez-Ramírez; M. Secco; P. Faria; P. N. Maravelaki; M. Ramesh; I. Papayianni; J. Válek. RILEM TC 277-LHS report: a review on the mechanisms of setting and hardening of lime-based binding systems. Materials and Structures 2021, 54, 1 -30.
AMA StyleJ. I. Alvarez, R. Veiga, S. Martínez-Ramírez, M. Secco, P. Faria, P. N. Maravelaki, M. Ramesh, I. Papayianni, J. Válek. RILEM TC 277-LHS report: a review on the mechanisms of setting and hardening of lime-based binding systems. Materials and Structures. 2021; 54 (2):1-30.
Chicago/Turabian StyleJ. I. Alvarez; R. Veiga; S. Martínez-Ramírez; M. Secco; P. Faria; P. N. Maravelaki; M. Ramesh; I. Papayianni; J. Válek. 2021. "RILEM TC 277-LHS report: a review on the mechanisms of setting and hardening of lime-based binding systems." Materials and Structures 54, no. 2: 1-30.
Concrete is one of the most fire‐resistant materials, whose resistance depends on the chemical and structural characteristics of the hydrated calcium silicate (C‐S‐H) formed in the hydration and hardening process. However, the structure and composition of this C‐S‐H varies with the time of hydration. The effect of the composition of the calcium silicate on the anhydrous material formed has been studied after subjecting it to an accelerated study of the effect of fire, irradiating it with a CO2 laser. Changes in the composition of C‐S‐H can lead to changes in the mechanical properties of the cement. C‐S‐H samples with different chemical composition (Ca/Si ratios 1 and 2) as well as different synthesis processes (double decomposition and hydrothermal) were studied. The crystalline phases obtained after heating were identified through micro‐Raman spectroscopy, which confirmed the formation of anhydrous calcium silicates with the same Ca/Si ratio as the initial one. In C‐S‐H gels with a Ca/Si ratio of over 1.5, stable Ca (OH)2 was formed. Scanning electron microscopy/energy dispersive X‐ray analysis analysis determined that in the process of heating with the laser, water is lost fast, generating porous structures. Such porosity is higher in materials with a lower Ca/Si ratio.
Moisés Martín‐Garrido; Sagrario Martínez‐Ramírez; Gloria Pérez; Ana M. Guerrero. Study of C‐S‐H dehydration due to temperature increase during fires. Journal of Raman Spectroscopy 2020, 51, 2318 -2327.
AMA StyleMoisés Martín‐Garrido, Sagrario Martínez‐Ramírez, Gloria Pérez, Ana M. Guerrero. Study of C‐S‐H dehydration due to temperature increase during fires. Journal of Raman Spectroscopy. 2020; 51 (11):2318-2327.
Chicago/Turabian StyleMoisés Martín‐Garrido; Sagrario Martínez‐Ramírez; Gloria Pérez; Ana M. Guerrero. 2020. "Study of C‐S‐H dehydration due to temperature increase during fires." Journal of Raman Spectroscopy 51, no. 11: 2318-2327.
This study analysed the fine particle (4AH13, C4AcH12) were identified during the pozzolanic reaction in CDW/lime system. Therefore, this type of waste can be reused as supplementary cementitious material with low-medium pozzolanic activity.
Moisés Frías; Raquel Vigil De La Villa; Sagrario Martínez-Ramírez; Lucía Fernández-Carrasco; Ernesto Villar-Cociña; Rosario García-Giménez. Multi-Technique Characterization of a Fine Fraction of CDW and Assessment of Reactivity in a CDW/Lime System. Minerals 2020, 10, 590 .
AMA StyleMoisés Frías, Raquel Vigil De La Villa, Sagrario Martínez-Ramírez, Lucía Fernández-Carrasco, Ernesto Villar-Cociña, Rosario García-Giménez. Multi-Technique Characterization of a Fine Fraction of CDW and Assessment of Reactivity in a CDW/Lime System. Minerals. 2020; 10 (7):590.
Chicago/Turabian StyleMoisés Frías; Raquel Vigil De La Villa; Sagrario Martínez-Ramírez; Lucía Fernández-Carrasco; Ernesto Villar-Cociña; Rosario García-Giménez. 2020. "Multi-Technique Characterization of a Fine Fraction of CDW and Assessment of Reactivity in a CDW/Lime System." Minerals 10, no. 7: 590.
The requirements for the formation of a protective patina on conventional weathering steels (WS) are well known in the scientific literature related to civil structures. However, these criteria are not always given due consideration when WS is used in cultural heritage, as in the case of sculptural work. An artificial patina was produced simulating artists’ working procedures using a direct patination technique, applying a solution of 10% H2SO4 on WS specimens. These were exposed for two years in the urban atmosphere of Madrid along with weathering steel specimens without artificial patina, called natural patina. The patinas generated have been analyzed using colorimetry, micro-Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thickness measurements.The artificial patina color formed hardly differs from the color that the natural patina acquires from practically the beginning of its formation in the atmosphere of Madrid. After two years, the atmospheric corrosion rate of patinated WS is lower than 6 µm/year. The sulfuric acid treatment accelerates the protective ability of the patina with respect to the natural patina according to the ratio goethite to lepidocrocite (α/γ). Chromium-rich goethite is located in the inner part of the artificial patina as well as chromium-rich ferrihydrite. Ferrihydrite may act as a precursor of nanophasic goethite.
Ana Crespo; Emilio Cano Díaz; Delphine Neff; Irene Llorente; Sagrario Martínez-Ramírez; Emilio Cano. Effect of Sulfuric Acid Patination Treatment on Atmospheric Corrosion of Weathering Steel. Metals 2020, 10, 591 .
AMA StyleAna Crespo, Emilio Cano Díaz, Delphine Neff, Irene Llorente, Sagrario Martínez-Ramírez, Emilio Cano. Effect of Sulfuric Acid Patination Treatment on Atmospheric Corrosion of Weathering Steel. Metals. 2020; 10 (5):591.
Chicago/Turabian StyleAna Crespo; Emilio Cano Díaz; Delphine Neff; Irene Llorente; Sagrario Martínez-Ramírez; Emilio Cano. 2020. "Effect of Sulfuric Acid Patination Treatment on Atmospheric Corrosion of Weathering Steel." Metals 10, no. 5: 591.
The calcium silicate hydrate gel (C–S–H) was synthesized by the double decomposition method because of the simplicity and the quickness of the procedure. The structure of the C–S–H gels after 1 week and 4 weeks in contact with the formation solution was studied through micro-Raman, Fourier transformed infrared spectroscopy and 29Si nuclear magnetic resonance. Simultaneous thermodifferential–thermogravimetric analysis and mass spectrometry (DTA/TG/MS) was used to identify the amount of calcium carbonate formed due to the reaction between the calcium and atmospheric CO2. With DTA/TG/MS, mass loss due to CO2 was observed to take place at temperatures below 400 °C, unidentified to date, which might be associated with the CO2 adsorbed on the C–S–H gel. Thus, in the TG analysis in the 300–430 °C range, both the loss of water due to the decomposition of the amorphous calcium carbonate and the loss of CO2 adsorbed on the gel must be considered. Additionally, polymerization of the gel and a decrease in the Ca/Si ratio was observed from the samples from 1 to 4 weeks.
Moisés Martín-Garrido; Sagrario Martínez-Ramírez. CO2 adsorption on calcium silicate hydrate gel synthesized by double decomposition method. Journal of Thermal Analysis and Calorimetry 2020, 143, 4331 -4339.
AMA StyleMoisés Martín-Garrido, Sagrario Martínez-Ramírez. CO2 adsorption on calcium silicate hydrate gel synthesized by double decomposition method. Journal of Thermal Analysis and Calorimetry. 2020; 143 (6):4331-4339.
Chicago/Turabian StyleMoisés Martín-Garrido; Sagrario Martínez-Ramírez. 2020. "CO2 adsorption on calcium silicate hydrate gel synthesized by double decomposition method." Journal of Thermal Analysis and Calorimetry 143, no. 6: 4331-4339.
The main component of the cement hydration, are both, the calcium silicate hydrate (C–S–H) and calcium silicate hydrate with Al (C–S(A)–H), whose composition is characterized by its calcium to silicon ratio (Ca/Si), which normally varies from 0.6 to 1.6. The theoretical Ca/Si ratios of the synthesized gels were compared with those of the experimental gels, which were determined by inductively coupled plasma atomic emission spectroscopy (ICP-OES). In addition, the microstructure of the gels was studied by spectroscopic techniques: infrared and Raman spectroscopy and nuclear magnetic resonance. By the double-decomposition method used in this work (1 day at 25 °C, inert atmosphere and pH = 12.3), only C–S–H and C–S(A)–H gels with a maximum Ca/Si ratio ranging from 0.8 to 1.0 were synthesized. However, the structures of the gels are slightly different as the Ca/Si ratio increases. Calcium silicate hydrate, with and without Al has been synthetized following double decomposition method, with different Ca/Si ratio. Analyzing Ca/Si ratio of the formed compounds, indicate that C–S(A)-H with Ca/Si ratios from 0.6 to 1.1 can be formed.
Moisés Martín-Garrido; M. Teresa Molina-Delgado; Sagrario Martínez-Ramírez. A comparison between experimental and theoretical Ca/Si ratios in C–S–H and C–S(A)–H gels. Journal of Sol-Gel Science and Technology 2019, 94, 11 -21.
AMA StyleMoisés Martín-Garrido, M. Teresa Molina-Delgado, Sagrario Martínez-Ramírez. A comparison between experimental and theoretical Ca/Si ratios in C–S–H and C–S(A)–H gels. Journal of Sol-Gel Science and Technology. 2019; 94 (1):11-21.
Chicago/Turabian StyleMoisés Martín-Garrido; M. Teresa Molina-Delgado; Sagrario Martínez-Ramírez. 2019. "A comparison between experimental and theoretical Ca/Si ratios in C–S–H and C–S(A)–H gels." Journal of Sol-Gel Science and Technology 94, no. 1: 11-21.
Non-fossil alternative fuels from biomass (agro-industrial, forestry and fodder plants) focus on getting cleaner, cheaper and more environmentally friendly energy sources directly related to the sustainable development of future societies. The resulting ash produced from the biomass calcination is a viable alternative for use as supplementary cementing materials in the construction industry. This study explores the scientific knowledge of calcium-silicate hydrate (C-S-H) gel formation during pozzolanic reaction between the biomass ash and calcium hydroxide through nuclear magnetic resonance technique with two different types of elephant grass ash that have different microstructure. The ash with the highest initial percentage of Q4 and Q3 units was found to react most actively and give rise to gels with the greatest inter-tetrahedral connectivity. In contrast, ash with higher content of total SiO2, exhibited lower reactivity and the C-S-H gel formed is characterised by low inter-tetrahedral connectivity from the earliest ages. Evaluation of C-S-H gel by nuclear magnetic resonance (NMR), as main hydrated phase for the engineering properties, revealed the potential of this tool to determine the effectiveness of this type of grass as raw material in cementing matrices through the evolution of the microstructure of the gel C-S-H formed.
Sagrario Martínez-Ramírez; Moisés Frías; Erika Y. Nakanishi; Holmer Savastano. Pozzolanic Reaction of a Biomass Waste as Mineral Addition to Cement Based Materials: Studies by Nuclear Magnetic Resonance (NMR). International Journal of Concrete Structures and Materials 2019, 13, 31 .
AMA StyleSagrario Martínez-Ramírez, Moisés Frías, Erika Y. Nakanishi, Holmer Savastano. Pozzolanic Reaction of a Biomass Waste as Mineral Addition to Cement Based Materials: Studies by Nuclear Magnetic Resonance (NMR). International Journal of Concrete Structures and Materials. 2019; 13 (1):31.
Chicago/Turabian StyleSagrario Martínez-Ramírez; Moisés Frías; Erika Y. Nakanishi; Holmer Savastano. 2019. "Pozzolanic Reaction of a Biomass Waste as Mineral Addition to Cement Based Materials: Studies by Nuclear Magnetic Resonance (NMR)." International Journal of Concrete Structures and Materials 13, no. 1: 31.
This study explored the viability of synthesising nanolime at ambient temperature by raising calcium solubility through the formation of complexes with dissolved sugars. Micro-Raman findings confirmed the formation of nanolime particles whilst the percentage of Ca(OH)2 formed, observed to vary with synthesis conditions, was calculated with thermogravimetry. Nanoparticles were synthesised most productively (77%) in a 5% sugary solution at a temperature of 25 °C and a 4 h reaction time. The hexagonal nanoparticles synthesised ranged in size from 200 to 25 nm. Portlandite formation is related to calcium complex formation with less mannitol that sucrose needed to form similar NPs of Ca(OH)2. The sugary media also favoured the formation of amorphous calcium carbonate.
Sagrario Martínez-Ramírez; Laura R. Higueruela; Ignacio Cascales; Moisés Martín-Garrido; María Teresa Blanco-Varela. New approach to nanolime synthesis at ambient temperature. SN Applied Sciences 2018, 1, 105 .
AMA StyleSagrario Martínez-Ramírez, Laura R. Higueruela, Ignacio Cascales, Moisés Martín-Garrido, María Teresa Blanco-Varela. New approach to nanolime synthesis at ambient temperature. SN Applied Sciences. 2018; 1 (1):105.
Chicago/Turabian StyleSagrario Martínez-Ramírez; Laura R. Higueruela; Ignacio Cascales; Moisés Martín-Garrido; María Teresa Blanco-Varela. 2018. "New approach to nanolime synthesis at ambient temperature." SN Applied Sciences 1, no. 1: 105.
The cement industry involves high-energy consumption that generates high CO2 emissions into the atmosphere. Environmental concerns can be addressed by replacing parts of Portland cement clinkers with pozzolanic materials in mortars and concrete. Slag, fly ash and silica fume are materials considered for the planned replacement. Research studies on clay minerals, such as kaolinite, are being followed with special attention by the scientific community and the cement industry. It is well known that these minerals require an activation process to transform kaolinite (K) into metakaolinite (MK). MK is an amorphous material from the transformation of K with high pozzolanic activity, which is its capacity to react with the portlandite released during the hydration of Portland cement, generating compounds such as C–S–H gels and some aluminum-phase hydrates. One of the MK production methods is heat treatment controlled by kaolinite at temperatures in the range of 600–900 ∘C. Different residues have been used (coal mining, paper sludge and waste from a drinking water treatment plant) activated at 600 ∘C for 2 h to elaborate blended cements. Due to their good behaviour as future eco-efficient additions, this research is a study by x-ray fluorescence (XRF), x-ray diffraction (XRD) and scanning electron microscopy (SEM) of their influence on the performances of blended cement mixtures (binary and ternary one), with substitutions of pozzolan ratio at 28 days of hydration. The porosity of pozzolanic cements decreases because of the formation of hydrated phases during pozzolanic reaction.
Rosario García Giménez; Raquel Vigil De La Villa Mencía; Moises Frías; Sagrario Martínez Ramírez; Iñigo Vegas Ramiro; Lucía Fernández Carrasco. Cements based on kaolinite waste. Advances in Geosciences 2018, 45, 133 -138.
AMA StyleRosario García Giménez, Raquel Vigil De La Villa Mencía, Moises Frías, Sagrario Martínez Ramírez, Iñigo Vegas Ramiro, Lucía Fernández Carrasco. Cements based on kaolinite waste. Advances in Geosciences. 2018; 45 ():133-138.
Chicago/Turabian StyleRosario García Giménez; Raquel Vigil De La Villa Mencía; Moises Frías; Sagrario Martínez Ramírez; Iñigo Vegas Ramiro; Lucía Fernández Carrasco. 2018. "Cements based on kaolinite waste." Advances in Geosciences 45, no. : 133-138.
The worldwide pursuit of new eco-efficient pozzolans is ongoing. Kaolinite-based waste is an eco-friendly source of recycled metakaolinite, a highly pozzolanic product. In this study, a blended cement paste containing 20% activated coal waste (ACW) was exposed to a 100% CO2 atmosphere at 65% RH for 7 days. The variations in its phase composition and strength were studied and compared to an OPC control. Both pastes were cured for 28 days prior to the carbonation test. Reaction kinetics were assessed using XRD, SEM/EDX, TG/DTG, FT-IR, Micro-Raman spectroscopy, pore solution pH and the cumulative carbonated fraction. The blended cement carbonated 68% faster than the control. While portlandite carbonation was the main reaction in both cements, decalcification was also observed (more intensely in the 20% ACW paste) in other hydraulic calcium phases (C-S-H gel, monocarboaluminate (C4AcH12), ettringite and tetracalcium aluminate (C4AH13). The end product of this reaction was calcium carbonate, mainly in the form of calcite, although traces of aragonite and amorphous carbonate were also detected. Compressive strength values rose with accelerated carbonation time and pore size reduction in both cement pastes.
Moises Frías; Raquel Vigil De La Villa; Rosario García; Olga Rodriguez; Lucía Fernández-Carrasco; Sagrario Martinez-Ramirez. Carbonation-Induced Mineralogical Changes in Coal Mining Waste Blended Cement Pastes and Their Influence on Mechanical and Microporosity Properties. Minerals 2018, 8, 169 .
AMA StyleMoises Frías, Raquel Vigil De La Villa, Rosario García, Olga Rodriguez, Lucía Fernández-Carrasco, Sagrario Martinez-Ramirez. Carbonation-Induced Mineralogical Changes in Coal Mining Waste Blended Cement Pastes and Their Influence on Mechanical and Microporosity Properties. Minerals. 2018; 8 (4):169.
Chicago/Turabian StyleMoises Frías; Raquel Vigil De La Villa; Rosario García; Olga Rodriguez; Lucía Fernández-Carrasco; Sagrario Martinez-Ramirez. 2018. "Carbonation-Induced Mineralogical Changes in Coal Mining Waste Blended Cement Pastes and Their Influence on Mechanical and Microporosity Properties." Minerals 8, no. 4: 169.
Kaolinite-based wastes are researched as an alternative means of extracting metakaolinite, a pozzolanic product for the manufacture of eco-efficient cements. However, both crystallinity and the content of this crystalline phase play important roles during their thermal activation and, therefore, in their subsequent behavior in the matrix with cementitious properties. In this study, the initial compositions of two thermally activated products (paper sludge and coal waste) are studied for both the mineralogy and the mechanical properties of binary cements. The elemental composition of the materials was analyzed with X-ray Fluorescence (XRF). The mineralogy of the crystalline materials was determined by X-ray Diffraction (XRD). The sample morphology was determined with scanning electron microscopy (SEM). The pozzolanic activity is measured by accelerated methods and the preparation of the specimens of blended cement is prepared following the procedure described by Kock-Steinegger. The results showed that the pozzolanic activity of the waste (in terms of fixed lime) was similar at 90 days but that its reaction rate was different. The pozzolanic reaction of both wastes produced stratlingite and C-S-H gels, with the presence of C4AH13. The C-S-H gel generated with coal waste had very short chains, was poorer in Ca and was rich in Al. The addition of both wastes to the cement modified its mineralogical composition in comparison with a conventional cement, favoring the formation of C4AH13 over the formation of ettringite.
Rosario García-Giménez; Moisés Frias; Raquel Vigil De La Villa; Sagrario Martínez-Ramírez. Ca/Si and Si/Al Ratios of Metakaolinite-Based Wastes: Their Influence on Mineralogy and Mechanical Strengths. Applied Sciences 2018, 8, 480 .
AMA StyleRosario García-Giménez, Moisés Frias, Raquel Vigil De La Villa, Sagrario Martínez-Ramírez. Ca/Si and Si/Al Ratios of Metakaolinite-Based Wastes: Their Influence on Mineralogy and Mechanical Strengths. Applied Sciences. 2018; 8 (4):480.
Chicago/Turabian StyleRosario García-Giménez; Moisés Frias; Raquel Vigil De La Villa; Sagrario Martínez-Ramírez. 2018. "Ca/Si and Si/Al Ratios of Metakaolinite-Based Wastes: Their Influence on Mineralogy and Mechanical Strengths." Applied Sciences 8, no. 4: 480.
Fire-induced compositional changes lead to strength loss and even failure in cement and concrete. Calcium silicate hydrate (C–S–H) gel, the main product of cement hydration, dehydrates at 25–200 °C, while temperatures of 850–900 °C alter its structure. A Raman spectroscopic study of the amorphous and crystalline phases forming after CO2 laser radiation of cement mortar showed that C–S–H dehydration yielded tricalcium silicate at higher, and dicalcium silicate at lower, temperatures. Post-radiation variations were identified in the position of the band generated by Si–O bond stretching vibrations.
Sagrario Martínez-Ramírez; Luis Díaz; Moisés Martín-Garrido; Lucia Fernández-Carrasco; David Torrens. In situ chemical modification of C–S–H induced by CO2 laser irradiation. Materials and Structures 2018, 51, 24 .
AMA StyleSagrario Martínez-Ramírez, Luis Díaz, Moisés Martín-Garrido, Lucia Fernández-Carrasco, David Torrens. In situ chemical modification of C–S–H induced by CO2 laser irradiation. Materials and Structures. 2018; 51 (1):24.
Chicago/Turabian StyleSagrario Martínez-Ramírez; Luis Díaz; Moisés Martín-Garrido; Lucia Fernández-Carrasco; David Torrens. 2018. "In situ chemical modification of C–S–H induced by CO2 laser irradiation." Materials and Structures 51, no. 1: 24.
Raquel Vigil de la Villa; Rosario García; Sagrario Martínez-Ramírez; Moisés Frías. Effects of calcination temperature and the addition of ZnO on coal waste activation: A mineralogical and morphological evolution. Applied Clay Science 2017, 150, 1 -9.
AMA StyleRaquel Vigil de la Villa, Rosario García, Sagrario Martínez-Ramírez, Moisés Frías. Effects of calcination temperature and the addition of ZnO on coal waste activation: A mineralogical and morphological evolution. Applied Clay Science. 2017; 150 ():1-9.
Chicago/Turabian StyleRaquel Vigil de la Villa; Rosario García; Sagrario Martínez-Ramírez; Moisés Frías. 2017. "Effects of calcination temperature and the addition of ZnO on coal waste activation: A mineralogical and morphological evolution." Applied Clay Science 150, no. : 1-9.
This paper studied in situ, by Micro-Raman spectroscopy, the very early hydration of C3A in the presence and absence of sulphates and with sucrose as an additive. For C3A hydration in the absence of gypsum, when carbonation is not avoided, carbonate-AFm phases are formed, but in the presence of gypsum, hydroxi-AFm are the main phases. Ettringite is the AFm stable phase developed initially at 70 min of hydration with gypsum and no monosulphate is formed. In the presence of sucrose, this salt, instead of sulphate, is adsorbed over the surface of the C3A, avoiding its reaction with sulphates until sucrose desorption. Three hours are necessary to lead to ettringite formation. A nucleation poisoning/adsorption surface mechanism is proposed for added sucrose systems.
Sagrario Martínez-Ramírez; Rocio Gutierrez-Contreras; Nuria Husillos; Lucia Fernández-Carrasco. In-situ reaction of the very early hydration of C3A-gypsum-sucrose system by Micro-Raman spectroscopy. Cement and Concrete Composites 2016, 73, 251 -256.
AMA StyleSagrario Martínez-Ramírez, Rocio Gutierrez-Contreras, Nuria Husillos, Lucia Fernández-Carrasco. In-situ reaction of the very early hydration of C3A-gypsum-sucrose system by Micro-Raman spectroscopy. Cement and Concrete Composites. 2016; 73 ():251-256.
Chicago/Turabian StyleSagrario Martínez-Ramírez; Rocio Gutierrez-Contreras; Nuria Husillos; Lucia Fernández-Carrasco. 2016. "In-situ reaction of the very early hydration of C3A-gypsum-sucrose system by Micro-Raman spectroscopy." Cement and Concrete Composites 73, no. : 251-256.
The application of a solid-state electrochemical technique, voltammetry of microparticles (VMP), for studying archeological lead glass is described. Upon attachment to graphite electrodes immersed into aqueous acetate buffer, characteristic voltammetric profiles were obtained for submicrosamples of archeological glasses dated between the 9th and 19th centuries. Bivariate and multivariate chemometric analyses of the VMP data allowed us to characterize individual workshops/provenances which enabled a clear discrimination between soda-rich and potash-rich glasses. An analysis of the VMP data, combined by XRF, FESEM, AFM and ATR-FTIR and Micro-Raman spectroscopies, denoted the presence of Pb(IV) centers accompanying network-former and network-modifier Pb(II).
Antonio Doménech-Carbó; Maria-Angeles Villegas; Fernando Agua; Sagrario Martínez-Ramírez; María Teresa Doménech-Carbó; Fernando Agua Martinez. Electrochemical Fingerprint of Archeological Lead Silicate Glasses Using the Voltammetry of Microparticles Approach. Journal of the American Ceramic Society 2016, 99, 3915 -3923.
AMA StyleAntonio Doménech-Carbó, Maria-Angeles Villegas, Fernando Agua, Sagrario Martínez-Ramírez, María Teresa Doménech-Carbó, Fernando Agua Martinez. Electrochemical Fingerprint of Archeological Lead Silicate Glasses Using the Voltammetry of Microparticles Approach. Journal of the American Ceramic Society. 2016; 99 (12):3915-3923.
Chicago/Turabian StyleAntonio Doménech-Carbó; Maria-Angeles Villegas; Fernando Agua; Sagrario Martínez-Ramírez; María Teresa Doménech-Carbó; Fernando Agua Martinez. 2016. "Electrochemical Fingerprint of Archeological Lead Silicate Glasses Using the Voltammetry of Microparticles Approach." Journal of the American Ceramic Society 99, no. 12: 3915-3923.
The stockpiling of tailings around coal mines poses a major environmental problem. Nonetheless, this clay mineral (kaolinite)-based waste can be reused as a supplementary cementitious material (recycled metakaolinite) in the manufacture of future eco-efficient cements. This paper explores the most significant scientific questions posed in connection with the conversion of this waste into pozzolans, such as the variation in product mineralogy depending on the sintering temperature and its effect on reaction kinetics in the pozzolan/Ca(OH)2 system over a period of 365 days. The findings show that the optimal sintering temperature is 600 °C, such that the cementitious properties of the activated product are determined solely by the conversion of kaolinite into metakaolinite and are unaffected by the other clay minerals (micas). The presence of 20% activated coal waste favors the formation of larger amounts of aluminous phases such as C4AH13 and C4AcH12 than in the reference paste and enhances C–S–H gel polymerization.
Moisés Frías; Rosario García; Raquel Vigil De La Villa; Sagrario Martínez-Ramírez. Coal Mining Waste as a Future Eco-Efficient Supplementary Cementing Material: Scientific Aspects. Recycling 2016, 1, 232 -241.
AMA StyleMoisés Frías, Rosario García, Raquel Vigil De La Villa, Sagrario Martínez-Ramírez. Coal Mining Waste as a Future Eco-Efficient Supplementary Cementing Material: Scientific Aspects. Recycling. 2016; 1 (2):232-241.
Chicago/Turabian StyleMoisés Frías; Rosario García; Raquel Vigil De La Villa; Sagrario Martínez-Ramírez. 2016. "Coal Mining Waste as a Future Eco-Efficient Supplementary Cementing Material: Scientific Aspects." Recycling 1, no. 2: 232-241.
A convenient ligand‐free catalytic system has been developed for the chemoselective cyclization reaction of various α‐allenol derivatives by palladium nanoparticles (PdNPs) in an aqueous reaction medium.
Benito Alcaide; Pedro Almendros; Ana M. González; Amparo Luna; Sagrario Martínez-Ramírez. Palladium Nanoparticles in Water: A Reusable Catalytic System for the Cycloetherification or Benzannulation of α-Allenols. Advanced Synthesis & Catalysis 2016, 358, 2000 -2006.
AMA StyleBenito Alcaide, Pedro Almendros, Ana M. González, Amparo Luna, Sagrario Martínez-Ramírez. Palladium Nanoparticles in Water: A Reusable Catalytic System for the Cycloetherification or Benzannulation of α-Allenols. Advanced Synthesis & Catalysis. 2016; 358 (12):2000-2006.
Chicago/Turabian StyleBenito Alcaide; Pedro Almendros; Ana M. González; Amparo Luna; Sagrario Martínez-Ramírez. 2016. "Palladium Nanoparticles in Water: A Reusable Catalytic System for the Cycloetherification or Benzannulation of α-Allenols." Advanced Synthesis & Catalysis 358, no. 12: 2000-2006.
Spent activated carbon is a by-product of potabilization plants. The present study explored the feasibility of valorizing this waste as an alternative fuel to replace oil coke in portland clinker furnaces. This involved determining its composition, calorific value, and ash and heavy metal content. Since the ash generated by spent activated carbon firing is taken up by the clinker, the possible effect of such uptake on clinkerization or the properties of the clinker obtained were also ascertained. Although spent activated carbon has an 18% lower calorific value than oil coke, one of the traditional cement kiln fuels, it was found to be apt for the purpose envisaged. Its ash content (10 wt%) is one order of magnitude higher than the ash content in coke. Spent activated carbon ash contains substantial proportions of anhydrite and quartz, hematite and augite, but consists primarily of amorphous matter (59 wt%). The effect of this ash on clinker phases was studied by clinkerizing raw meal in which it was used as a replacement for clay. Such meal exhibited high burnability and yielded clinkers with a composition and mineralogy comparable to the properties found in the industrial product. The sulfate present in the ash induced substantial alite crystal growth in the clinker. The loss of minority elements during clinkerization was likewise studied.
Nuria Husillos Rodríguez; Sagrario Martínez-Ramírez; María Teresa Blanco-Varela. Activated carbon as an alternative fuel. Effect of carbon ash on cement clinkerization. Journal of Cleaner Production 2016, 119, 50 -58.
AMA StyleNuria Husillos Rodríguez, Sagrario Martínez-Ramírez, María Teresa Blanco-Varela. Activated carbon as an alternative fuel. Effect of carbon ash on cement clinkerization. Journal of Cleaner Production. 2016; 119 ():50-58.
Chicago/Turabian StyleNuria Husillos Rodríguez; Sagrario Martínez-Ramírez; María Teresa Blanco-Varela. 2016. "Activated carbon as an alternative fuel. Effect of carbon ash on cement clinkerization." Journal of Cleaner Production 119, no. : 50-58.