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1. Chloride migration and long-term natural carbonation on concretes with calcined clays: A study of calcined clays in Argentina

Author

Gisela Cordoba, Ricarda Sposito, Mathias Köberl, Silvina Zito, Nancy Beuntner, Alejandra Tironi, Karl-Christian Thienel, and Edgardo F. Irassar

Subjects
Calcined common brick clay, Calcined low-grade kaolinitic clay, Concrete, Chloride ingress, Carbonation, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

The use of calcined clays as supplementary cementitious materials is one of the strategies to reduce the CO2 emissions from cement and concrete industry as they provide good mechanical and durable properties after proper calcination and grinding. In Argentina, calcined common brick clays have a significant relevance due to their proximity to the largest Portland cement plants. The aim of this study is to analyze the resistance to chloride ingress and natural carbonation up to 36 months of concretes using calcined common brick clay and calcined low-grade kaolinitic clay. The latter exhibits a much lower chloride migration coefficient than the Portland cement concrete from 28 days on, while the calcined common brick clay requires a 90 days curing to obtain lower chloride ingress. Although the blended concretes exhibit greater carbonation depths than the reference after 36 months, it is lower than the given threshold of 10 mm. Hence, durable concretes with calcined clay can be obtained if they are properly cured.

Published
2022
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2. DESARROLLO DE MICROESTRUCTURA EN CEMENTOS MEZCLA ELABORADOS CON ARCILLAS CAOLINÍTICAS CALCINADAS DE MEDIANO GRADO: EFECTO EN INDICADORES DE DURABILIDAD

Author

Martín N. Humberto, Alejandra Tironi, Alberto N. Scian, and Edgardo F. Irassar

Subjects
calcined kaolinitic clays, microstructure, water absorption, water vapor diffusion, Engineering (General). Civil engineering (General), TA1-2040, Science (General), Q1-390
Abstract

The objective of this work is to evaluate the influence of the structural arrangement of kaolinite present in medium grade clays, calcined and ground, on the development of the microstructure of pastes and its effect on durability indicators. For this purpose, three kaolinitic clays were used, then blended cements containing 25% of calcined clays were elaborated. The evolution of the microstructure in pastes was studied using XRD, DTA/TG and MIP. Two durability indicators were determined in mortars at 28 days: capillary suction velocity and water vapor diffusion coefficient. The results obtained show that, for clays with similar kaolinite content, the disordered structure of kaolinite will favor resistance to water transport (smaller pore volume with diameter greater than 60 nm) and will not be favorable for water vapor transport (larger pore volume with diameter less than 30 nm).

Published
2021

3. COMPARACIÓN DE LA EFECTIVIDAD DE ARCILLAS CAOLINÍTICAS CON ESTRUCTURA ORDENADA Y DESORDENADA PARA LA REMOCIÓN DE Cd(II)

Author

Gisele Portela, Alejandra Tironi, and Claudia C. Wagner

Subjects
clay, kaolinite, adsorption, cadmiun, Engineering (General). Civil engineering (General), TA1-2040, Science (General), Q1-390
Abstract

The presence of cadmiun in the environment has increased in the last century by anthropogenic factors. Clay minerals have proven to be useful as adsorbents of, among other substances, heavy metals; due to the high availability and low cost of the process. In this work, we evaluated the effectiveness of two clays with medium percentage of kaolinitic mineral available in Argentina, one with an ordered structure and the other with a disordered structure to remove Cd(II) from aqueous solutions. Under the operated conditions (initial concetration of Cd(II) 2-75 mg/L, 100 mL solution, 2 g/L of clay, 180 min of stirring, 22ºC) it was concluded that the disordered kaolinite has a greater adsorption capacity at low concentrations of Cd(II while orderly structure kaolinite for high Cd(II) concentrations. In addition, it was observed that the adsorption process can be effectively studied using the Freundlich and Langmuir isotherms

Published
2020

4. Study of excavated clays with kaolinite and dickite as pozzolanic materials

Author

Hernan Yanguatin, Alejandra Tironi, and Jorge Iván Tobón

Subjects
calcined clay, low grade clay, pozzolans, waste valorisation, kaolinite, Technology, Mining engineering. Metallurgy, TN1-997
Abstract

In the present study, samples of excavated waste clays were thermally activated at 550 °C and 650 °C, these clays with low kaolinite content and presence of dickite have a limited industrial exploitation but are widely availability in developing countries and have the potential to use as pozzolanic material. The effects on the calcium hydroxide fixation and the compressive strength were evaluated in lime pastes and mortars blended with calcined excavated clays. The experimental results and statistical modelling using multiple regression analysis showed that the compressive strength at 28 days increased 5%, when the kaolinite increased up to 20% and dickite up to 40%, for a clay with SSA of 4000 cm2/g and calcined at 550 °C. Also, by increasing SSA up to 6000 cm2/g and calcination temperature up to 650 °C, the compressive strength increased 10% and 15%, respectively.

Published
2022
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5. Influencia del grado de molienda en la actividad puzolánica de arcillas que contienen caolinita y halloysita

Author

Leonardo Cabrera, Alejandra Tironi, Alberto N. Scian, and Edgardo F. Irassar

Subjects
Engineering (General). Civil engineering (General), TA1-2040, Science (General), Q1-390
Abstract

El objetivo de este trabajo es analizar la influencia del grado de molienda en la actividad puzolánica de diferentes arcillas que contienen los minerales Caolinita y/o Halloysita. Se utilizaron 4 arcillas, cuantificando la fase amorfa formada durante la calcinación a 700 ºC y realizando distintos procesos de molienda. Se determinó que la actividad puzolánica de las arcillas calcinadas depende de la composición mineralógica y defectos superficiales, cantidad de fase amorfa y finura. La mayor actividad puzolánica fue obtenida para la arcilla con un elevado contenido de Halloysita finamente molida. La utilización de un 25% de reemplazo de cemento Portland (CP) por esta muestra permite superar la resistencia a la compresión respecto al mortero-CP a partir de los 7 días.

Published
2016

6. Influence of different calcined clays on the water transport performance of concretes

Author

Silvina Vanessa Zito, Alejandra Tironi, Ricarda Sposito, Gisela Paola Cordoba, Karl-Christian Thienel, Edgardo Fabián Irassar, and Viviana Rahhal

Subjects
General Materials Science, Building and Construction, Civil and Structural Engineering
Abstract

This study compares the pozzolanic activity of kaolinitic and illite clays after calcination as they are the most abundant types of clays worldwide. The impact of calcined clays on microstructure development was tested by determining the porosity of cement paste as well as by phase and optical analysis of the cement matrix and the interfacial transition zone of concrete. As water transportation with damaging carbonate or chloride ions is the main reason for reduced durability of reinforced concrete, the results were complemented with water absorption tests on blended concretes. At 28 days, the system with calcined kaolinitic clay revealed a higher densification of its microstructure with a lower water absorption rate compared with plain concrete and concrete with calcined illite clay, which is related to its higher pozzolanic reactivity. Nonetheless, calcined illite clays can be considered as a low-cost clinker replacement as a significant pozzolanic contribution is detectable and after 90 days, the water absorption behaviour is comparable to those of the other systems investigated.

Published
2022
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7. Concretes with Calcined Clay and Calcined Shale: Workability, Mechanical, and Transport Properties

Author

Alejandra Tironi, Edgardo F. Irassar, Ricarda Sposito, Christian Thienel, Gisela Cordoba, Silvina Vanessa Zito, and Viviana Fátima Rahhal

Subjects
Cement, Materials science, Metallurgy, 0211 other engineering and technologies, 020101 civil engineering, Blended cement, 02 engineering and technology, Building and Construction, Pozzolan, engineering.material, 0201 civil engineering, law.invention, Slump, Mechanics of Materials, law, 021105 building & construction, Illite, engineering, General Materials Science, Calcination, Oil shale, Civil and Structural Engineering
Abstract

This paper analyzed the eco-efficiency of concretes (water/cement ratio = 0.50; cement content=350 kg/m3, and slump = 7 cm) with blended cement containing 25% by weight calcined pozzolan o...

Published
2020
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8. Durability of Concrete Containing Calcined Clays: Comparison of Illite and Low-Grade Kaolin

Author

Alejandra Tironi, Viviana Fátima Rahhal, Edgardo F. Irassar, Silvina Vanessa Zito, and Gisela Cordoba

Subjects
Materials science, Sorptivity, Carbonation, Penetration (firestop), Chloride, Penetration test, law.invention, Slump, Portland cement, law, medicine, Composite material, Curing (chemistry), medicine.drug
Abstract

In this paper, durability parameters (water sorptivity, water penetration, chloride penetration and natural carbonation) are studied on conventional mixtures (w/cm = 0.50). Concretes were elaborated with Portland cement (PC) and blended Portland cements, containing 25% replacement by illitic calcined clay (ICC) and low-grade kaolinitic calcined clay (KCC). They were characterized by slump, compressive and tensile strengths and bulk porosity. Water sorptivity (ASTM C 1585) was determined on concretes cured 2, 7 and 28 days; water penetration test (EN 12390) and chloride penetration (ASTM C 1556) were determined on concretes cured 28 days. Carbonation depth undergoing a good and very good curing was assessed using a phenolphthalein indicator at 3 and 6 months of natural exposition. Results show that water sorptivity is reduced when concrete is curing for 2, 7 and 28 days for all concretes. KCC has a significantly lower sorptivity than PCC and ICC. At 28 days, the water penetration is deeper for ICC and lower for KCC concrete. All concretes have similar apparent chloride diffusion coefficients. After six months, the natural carbonation of all concretes is less than 2 mm, with a slightly lower performance of ICC and KCC than PCC.

Published
2020
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9. Thermal Treatment and Pozzolanic Activity of Calcined Clay and Shale

Author

H. Donza, Edgardo F. Irassar, Viviana Fátima Rahhal, Alejandra Tironi, Mónica Adriana Trezza, Alberto Nestor Scian, Viviana L. Bonavetti, and C. Cristina Castellano

Subjects
Materials science, CALCINED CLAY, Thermal treatment, INGENIERÍAS Y TECNOLOGÍAS, engineering.material, law.invention, THERMAL TREATMENT, law, Ingeniería de los Materiales, General Materials Science, Calcination, POZZOLAN, Pozzolanic activity, Civil and Structural Engineering, ILLITE, POZZOLANIC INDEX, Metallurgy, Building and Construction, Pozzolan, KAOLIN, CALCINED SHALE, SMECTITE, Illite, engineering, Clay minerals, Oil shale
Abstract

Clayminerals are the most abundant raw materials for calcined pozzolans. Thermaltransformation includes dehydration, dehy­droxylation, mineral collapse, andneo-formation. Depending on the type and amount of clay mineral, and the natureand amount of associated minerals, the thermal treatment determines the pozzo­lanicactivity. In this paper, 10 natural shales or clays (six illite, two kaolin,and two loess) from Buenos Aires Province (Argentina) were identified using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), andthermogravimetry (TG). The thermal transformation was checked by XRD or FTIR and the elec­trical conductivity (EC) at the calcination window. The pozzolanicactivity was evaluated using the Frattini test and strength activity index (SAI). The Frattini test gives positive results after 7 days and SAI is greaterthan 0.90 at 28 days, but the compressive strength development depends on mainclay mineral. The EC was effec­tive to evaluate the Ca(OH)2 fixationduring the first time and it is related to the specific surface obtained. Fil: Irassar, Edgardo Fabián. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Ingeniería Civil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Tironi, Alejandra. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Ingeniería Química; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Bonavetti, Viviana Lidia. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Ingeniería Civil; Argentina Fil: Trezza, Mónica Adriana. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Ingeniería Química; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Castellano, Claudia Cristina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Ingeniería Civil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Rahhal, Viviana Fátima. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Ingeniería Civil; Argentina Fil: Donza, Horacio Ariel. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría. Departamento de Ingeniería Civil; Argentina Fil: Scian, Alberto Nestor. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina

Published
2019

10. Effect of thermal treatment on pozzolanic activity of excavated waste clays

Author

Jose H. Ramírez, Jorge Iván Tobón, Alejandra Tironi, and Hernan Yanguatin

Subjects
Materials science, Otras Ingeniería de los Materiales, 0211 other engineering and technologies, 020101 civil engineering, 02 engineering and technology, Thermal treatment, INGENIERÍAS Y TECNOLOGÍAS, 0201 civil engineering, law.invention, chemistry.chemical_compound, CALCINED EXCAVATED CLAYS, law, Specific surface area, POZZOLANS, FRATTINI TEST, Ingeniería de los Materiales, 021105 building & construction, General Materials Science, Calcination, Pozzolanic activity, Civil and Structural Engineering, Calcium hydroxide, Metallurgy, Building and Construction, Factorial experiment, KAOLINITE, CALCIUM HYDROXIDE FIXATION, EXCAVATED WASTE CLAYS, INCREASE PERCENTAGE OF COMPRESSIVE STRENGTH, Compressive strength, chemistry, Granulometry
Abstract

Samples of excavated waste clays were characterized by X-ray fluorescence, laser granulometry, specific surface area, X-ray diffraction, and thermo-gravimetric analysis. Excavated clays were calcined at 550 ºC and 650 ºC in order to investigate their potential pozzolanic activity. The effect of thermal activation also was determined by factorial experiments with two factors in randomized complete blocks. Pozzolanic activity was evaluated by calcium hydroxide fixation, the Frattini test and the compressive strength at 7 and 28 days. The results indicate that calcined excavated clays at 650 ºC presented pozzolanic activity at 7 days and showed an increase percentage of compressive strength on average 13%. Fil: Yanguatin, Hernán Gonzalo. Universidad Nacional de Colombia; Colombia Fil: Ramírez, José Herney. Universidad Nacional de Colombia; Colombia Fil: Tironi, Alejandra. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Tobón, Jorge I.. Universidad Nacional de Colombia; Colombia

Published
2019

11. Effect of cement composition on the early hydration of blended cements with natural zeolite

Author

Viviana Fátima Rahhal, Alejandra Tironi, Mónica Adriana Trezza, Robert Černý, Edgardo F. Irassar, Claudia C. Castellano, and Zby ek Pavlík

Subjects
Materials science, CLINOPTILOLITE, 0211 other engineering and technologies, INGENIERÍAS Y TECNOLOGÍAS, 02 engineering and technology, 01 natural sciences, law.invention, law, CEMENT, 021105 building & construction, Physical and Theoretical Chemistry, Composite material, Pozzolanic activity, Zeolite, ISOTHERMAL CALORIMETRY, Cement, Clinoptilolite, HYDRATION, technology, industry, and agriculture, Condensed Matter Physics, 010406 physical chemistry, 0104 chemical sciences, Dilution, Portland cement, Compressive strength, Ingeniería Civil, ZEOLITE, Pozzolanic reaction, CATION EXCHANGE, Otras Ingeniería Civil
Abstract

This paper studies the addition (0–40% w/w) of natural zeolite (NZ, 84% clinoptilolite) in blended cements made with Portland cement (PC) with low and medium C3A content. The isothermal calorimetry was used to understand the effect of NZ on the early cement hydration. For low C3A cement, the addition of NZ produces mainly a dilution effect and then the heat released curve is similar to plain cement with lower intensity. For medium C3A cement, the curve shows the C3S peak in advance and a high intensity of third peak attributed to C3A hydration. The high cation fixed of NZ reduces the ions concentration (especially alkalis) in the mixing water stimulating the PC hydration. The flowability decreases when the NZ replacement level increases. Results of Fratini’s test show that NZ with both PCs used presents slow pozzolanic activity. At early age, XRD and FTIR analyses confirm that hydration products are the same as that of the corresponding PC and the CH is progressively reduced after 28 days and some AFm phases (hemi- and monocarboaluminate) appear depending on the NZ percentage and the PC used. For low replacement levels, the compressive strength is higher than the corresponding PC from 2 to 28 days. For high replacement levels, the early compressive strength is lower than that of corresponding plain PC and the pozzolanic reaction improves the later compressive strength of blended cements. Fil: Rahhal, Viviana Fátima. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Pavlík, Zby?ek. Czech Technical University in Prague; República Checa Fil: Tironi, Alejandra. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Castellano, Claudia Cristina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Trezza, Mónica Adriana. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Černý, Robert. Czech Technical University in Prague; República Checa Fil: Irassar, Edgardo Fabián. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina

Published
2016
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12. Thermal Activation of Two Complex Clays (Kaolinite-Pyrophillite-Illite) from Tandilia System, Buenos Aires, Argentina

Author

Alejandra Tironi, Edgardo F. Irassar, and Mónica Adriana Trezza

Subjects
Materials science, engineering.material, Feldspar, Hydrothermal circulation, law.invention, Chemical engineering, law, Differential thermal analysis, visual_art, Illite, engineering, visual_art.visual_art_medium, Kaolinite, Calcination, Cementitious, Pozzolanic activity
Abstract

The aim of this work is focused to identify natural resources with industrial potential to be used as supplementary cementitious materials (SCMs) in Portland blended cements. Two clays obtained from the quarries near to Barker in Tandilia System (Buenos Aires- Argentina) were studied. The geneses of these rocks are by a hydrothermal alteration and include the presence of pyrophillite. Whole-rock were characterized by XRD and FTIR spectroscopy indicating that main clayed minerals are kaolinite (Si2Al2O5(OH)4), illite (K0.66Si3.33Al2.66O10(OH)2) and pyrophillite (Si4Al2O10(OH)2) associated with feldspar. The thermal transformation was studied by differential thermal analysis and the phase changes were confirmed by XRD and FTIR. Samples of clays were calcined at different temperature (550 to 1050 °C), the electrical conductivity was measured and the dissolved silica in simulated pore water solution was quantified. The pozzolanic activity was measured by the compressive strength activity index, on blended cement mortars containing 25% by weight of calcined clays.

Published
2017
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13. Blended Cements with Calcined Illitic Clay: Workability and Hydration

Author

Jaroslav Pokorny, Zbyšek Pavlík, Robert Černý, Viviana Fátima Rahhal, Edgardo F. Irassar, Mónica Adriana Trezza, Alejandra Tironi, and Guillermina Marchetti

Subjects
Pore size, 0211 other engineering and technologies, 020101 civil engineering, Blended cement, 02 engineering and technology, 0201 civil engineering, law.invention, Portland cement, Compressive strength, Particle packing, law, 021105 building & construction, Geotechnical engineering, Calcination, Composite material, Geology
Abstract

In this paper, the paste workability and hydration progress of blended cements containing different calcined illitic clays were studied. For blended cements with different replacement percentages, the particle packing, the water film thickness (WFT) and the flow spread was modelled and measured. Results indicate that blended cement with ground illitic calcined clays maintain or reduce the packing, so the flow spread of blended cement pastes decrease when the replacement percentage increases. For blended cements with 25% of calcined illitic clay, the early hydration was described by the calorimetric curve, and later the hydration products were analysed by XRD and TG analysis and the pore size distribution (MIP) at 2, 7, 28 and 91 days. Finally, the performance of blended cements was evaluated by the compressive strength. For blended cements, the hydration products are similar to that corresponding to ordinary Portland Cement (OPC) and it also produce a pore size refinement that improve the compressive strength at later age.

Published
2017
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14. Hydration of Blended Cement with Halloysite Calcined Clay

Author

Alberto Nestor Scian, Alejandra Tironi, Edgardo F. Irassar, and Fernanda Cravero

Subjects
Materials science, Pozzolan, engineering.material, Halloysite, law.invention, Compressive strength, Chemical engineering, law, Differential thermal analysis, engineering, Kaolinite, Calcination, Cementitious, Porosity
Abstract

The effects of calcined kaolinitic clays as supplementary cementitious materials (SCMs) on the performance of pastes and mortars have been well studied. Less attention has been paid to the thermal transformation of halloysite than that of kaolinite and its possibility to be used as SCMs. Halloysite and kaolinite have identical chemical composition, except that halloysite may have two molecules of H2O, as interlayer water. The content of additional water in the interlayers of halloysite has a decisive influence on the crystal morphology, which is generally curled rather than platy as in kaolinite. Common forms are elongated tubes and spheroids. The aim of this investigation is to study the hydration of blended cements with 25% of different calcined clays to evaluate the influence of the content and the morphology of halloysite in the development of the hydratation compounds, and compressive strength of mortars. Three clays with different halloysite/kaolinite content, and different morphology were analyzed. The hydrated phases present in pastes at 2, 7, and 28 days were identified by X-ray diffraction (XRD), and the content of CH by differential thermal analysis (DTA/TG). The compressive strength of mortars was tested at 2, 7, and 28 days. The pozzolanic reactivity of the calcined clays was influence by the kaolinite content and morphology of halloysite in natural clays. This results in different crystalline and amorphous aluminic phases obtained at different ages, and that the ensemble results differ, this affects the porosity and the compressive strength.

Published
2017
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15. Pozzolanic activity of calcined halloysite-rich kaolinitic clays

Author

Alejandra Tironi, Edgardo F. Irassar, Fernanda Cravero, and Alberto Nestor Scian

Subjects
Recubrimientos y Películas, CALCINED CLAY, POZZOLANIC ACTIVITY, 0211 other engineering and technologies, Mineralogy, 020101 civil engineering, 02 engineering and technology, INGENIERÍAS Y TECNOLOGÍAS, engineering.material, Halloysite, 0201 civil engineering, law.invention, Geochemistry and Petrology, law, FRATTINI TEST, Ingeniería de los Materiales, 021105 building & construction, Kaolinite, Calcination, Pozzolanic activity, HALLOYSITE, Geology, KAOLINITE, STRENGTH ACTIVITY INDEX, Chemical engineering, engineering
Abstract

The aim of this study is to determine the pozzolanic activity of clays with high content of halloysite/kaolinite, and to evaluate the influence of halloysite/kaolinite ratio and halloysite morphology in the development of pozzolanic activity of the calcined clays. For this purpose, three different natural clays from Río Negro Province, Argentine, were selected and completely characterized. After calcined at 700 °C and ground to 80% of particle size < 45 μm, pozzolanic activity was determined using the electrical conductivity test, the Frattini test and the compressive strength index. Results show that all calcined clays are classified as high reactive pozzolana. The presence of kaolinite and spheroidal halloysite exerts great influence at early ages; while tubular halloysite has greater influence in the pozzolanic activity and the compressive strength of mortars at later ages. Fil: Tironi, Alejandra. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Cravero, Maria Fernanda. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina Fil: Scian, Alberto Nestor. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina Fil: Irassar, Edgardo Fabián. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina

Published
2017

16. Complex Characterization and Behavior of Waste Fired Brick Powder-Portland Cement System

Author

Alejandra Tironi, Edgardo F. Irassar, Jaroslav Pokorný, Claudia C. Castellano, Milena Pavlíková, Zbyšek Pavlík, Viviana Fátima Rahhal, Mónica Adriana Trezza, and Ondřej Jankovský

Subjects
red ceramic waste, Materials science, 0211 other engineering and technologies, 02 engineering and technology, lcsh:Technology, Article, law.invention, chemistry.chemical_compound, law, 021105 building & construction, physical and chemical parameters, General Materials Science, Calcium aluminates, Ceramic, lcsh:Microscopy, Pozzolanic activity, lcsh:QC120-168.85, Cement, heat of hydration, Brick, lcsh:QH201-278.5, lcsh:T, Metallurgy, Pozzolan, 021001 nanoscience & nanotechnology, pozzolan, Portland cement, Compressive strength, chemistry, lcsh:TA1-2040, visual_art, analysis of hydrated products, visual_art.visual_art_medium, lcsh:Descriptive and experimental mechanics, lcsh:Electrical engineering. Electronics. Nuclear engineering, lcsh:Engineering (General). Civil engineering (General), 0210 nano-technology, lcsh:TK1-9971
Abstract

Two waste fired brick powders coming from brick factories located in Argentine and Czech Republic were examined as alternative mineral admixtures for the production of blended cements. In pastes composition, local Portland cements (Argentine and Czech) were substituted with 8&ndash, 40%, by mass, with powdered ceramic waste. For the ceramic waste-Portland cement system, workability, the heat released, pozzolanity, specific density, compressive strength, hydrated phases, porosity, and pore size distribution were tested. The relevance of the dilution effect, filler effect, and pozzolanic activity was analyzed to describe the general behavior of the pozzolan/cement system. The properties and performance of cement blends made with finely ground brick powder depended on the composition of ceramic waste and its reactivity, the plain cement used, and the replacement level. Results showed that the initial mini-slump was not affected by a low ceramic waste replacement (8% and 16%), and then it was decreased with an increase in the ceramic waste content. Brick powder behaved as a filler at early ages, but when the hydration proceeded, its pozzolanic activity consumed partially the calcium hydroxide and promoted the formation of hydrated calcium aluminates depending on the age and present carbonates. Finally, blended cements with fired brick powder had low compressive strength at early ages but comparable strength-class at later age.

Published
2019
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17. Assessment of pozzolanic activity of different calcined clays

Author

Edgardo F. Irassar, Alejandra Tironi, Mónica Adriana Trezza, and Alberto Nestor Scian

Subjects
Calcium hydroxide, Materials science, Mineralogy, Building and Construction, Pozzolan, engineering.material, law.invention, chemistry.chemical_compound, Montmorillonite, chemistry, Chemical engineering, law, engineering, Pozzolanic reaction, General Materials Science, Calcination, Pozzolanic activity, Metakaolin, Lime
Abstract

The pozzolanic activity of calcined clays depends on the type and amount of clayed minerals, the nature and amount of impurities, the thermal treatment used for its activation and the specific surface obtained after calcination. In this paper, four test methods for assessment the pozzolanic activity on seven calcined clays (five kaolinites and two bentonites) were analyzed. Natural clays were calcined and investigated by two direct tests (Frattini and saturated lime) and two indirect tests (strength activity index and electrical conductivity). Frattini test and the strength activity index (SAI) were found to be the most accurate and reliable methods to assess pozzolanic activity over time. Frattini test evaluates accurately the calcium hydroxide (CH) consumption by pozzolanic reaction, and SAI test discriminates the real contribution of pozzolanic reaction to densification of microstructure. The electrical conductivity (EC) and the lime consumption (LC) tests evaluate the ability of pozzolanic material to fix CH during the first time of contact and their results are correlated with the specific surface of calcined clay.

Published
2013
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18. Kaolinitic calcined clays: Factors affecting its performance as pozzolans

Author

Edgardo F. Irassar, Alejandra Tironi, Mónica Adriana Trezza, and Alberto Nestor Scian

Subjects
Cement, NATURAL CLAYS, Materials science, Metallurgy, Mineralogy, INGENIERÍAS Y TECNOLOGÍAS, Building and Construction, Pozzolan, KAOLINITE, METAKAOLINITE, Cerámicos, law.invention, law, CEMENT, Ingeniería de los Materiales, Kaolinite, General Materials Science, Calcination, POZZOLANA, Pozzolana, Civil and Structural Engineering
Abstract

Five natural kaolinitic clays from different regions of Argentine, with different kaolinite content, different impurities and different degree of crystallinity were calcined in a fixed-bed electrical furnace at 700 °C. Clays were characterized by X-ray diffraction (XRD) and Fourier transformed infra-red spectrometry (FTIR) that provides an index about the order/disorder of the structure. After heat treatment, the structural changes were characterized by XRD and FTIR, and pore size distribution and specific surface were determined. Their pozzolanic activity was evaluated with the Frattini test, electrical conductivity in saturated Ca(OH) 2 solution and compressive strength on mortars at 7, 28 and 90 days. Among tested clays, four of them can be classified as pozzolan by the Frattini test. The pozzolanic activity of the natural clays showed good correlation with the content of kaolinite, the inversed of structure order determined by FTIR, and the specific surface of calcined clays. This study confirms that natural clays other than pure kaolinite can be interesting pozzolanic materials when thermally activated. Fil: Tironi, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría; Argentina Fil: Trezza, Mónica Adriana. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría; Argentina Fil: Scian, Alberto Nestor. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina Fil: Irassar, Edgardo Fabián. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría; Argentina

Published
2012
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19. Ternary Blended Cement with Limestone Filler and Kaolinitic Calcined Clay

Author

Edgardo F. Irassar, Alberto Nestor Scian, and Alejandra Tironi

Subjects
Materials science, Blended cement, engineering.material, law.invention, Portland cement, Compressive strength, law, Phase (matter), Filler (materials), Pozzolanic reaction, engineering, Calcination, Composite material, Ternary operation
Abstract

The use of calcined clays providing from low grade kaolinitic clays combined with the limestone filler in ternary blended cement formulation has received considerable attention in recent years. This paper describes the results of a research project to study the behavior of kaolinitic calcined clays (CC) in combination with limestone filler (F). Blended cements were obtaining replacing CC (0–30 %) and F (0–10 %) by mass by Portland cement (PC). The pozzolanicity of blended cement was assessed by the Frattini tests at 2, 7 and 28 days. The response of the system was evaluated in terms of flow, and the compressive strength at 2, 7 and 28 days. The hydration progress was determined by the type and amount of hydration compounds at 2, 7 and 28 days using the Rietveld method. The change in pore size distribution was determined by mercury intrusion porosimetry (MIP). Hydrated phases obtained correspond to the pozzolanic reaction (contribution CC) and phase stabilization (contribution F) modifying the pore structure and all factors contribute to develop acceptable mechanical properties with a large reduction of energy consumption and CO2 emission.

Published
2015
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20. Blended Cements with Kaolinitic Calcined Clays: Study of the Immobilization of Cr(VI)

Author

Edgardo F. Irassar, Alberto Nestor Scian, Alejandra Tironi, and Mónica Adriana Trezza

Subjects
Cement, Materials science, Waste management, chemistry.chemical_element, law.invention, Portland cement, Chromium, Crystallinity, chemistry, Chemical engineering, law, Pozzolanic reaction, Kaolinite, Calcination, Pozzolanic activity
Abstract

Numerous investigations on the immobilization of chromium in cement-based systems were carried out in the recent years. The aim of this study is to analyze the influence of the crystallinity of kaolinite used to make calcined kaolinitic clay when are used in pastes for immobilization of Cr(VI). In previous study, it was found that the reactivity of kaolinitic calcined clays used as partial replacement of Portland cement largely depends on the crystallinity of kaolinite in the raw clay. Calcined clays obtained from raw materials containing kaolinite with disordered structure presents a very high pozzolanic activity allowing high-percentage replacement (30 %) in blended cements. In this study, pastes of blended cement with 15 % and 30 % by mass of two kaolinitic calcined clays (order and disorder structure of kaolinite) were elaborated using a solution of 5000 ppm of K2Cr2O7 and a solution-to-cementing material ratio of 0.50. The immobilization efficiency was measurement by lixiviation test and the modifications in the hydrated phases was studied by X-ray diffraction and SEM/EDS analysis. The results shown that kaolinitic calcined clay from ordered kaolinite was more efficient than disordered kaolinite to retention of Cr(VI), reaching values higher than that of PC-paste.

Published
2015
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21. Red Ceramic Wastes: A Calcined Clay Pozzolan

Author

Alejandra Tironi, Tereza Kulovaná, Jaroslav Pokorný, Robert Černý, Edgardo F. Irassar, Zbyšek Pavlík, Viviana Fátima Rahhal, C. Cristina Castellano, and Mónica Adriana Trezza

Subjects
Cement, Materials science, Mineralogy, Pozzolan, law.invention, Slump, Portland cement, Compressive strength, Chemical engineering, law, visual_art, visual_art.visual_art_medium, Pozzolanic reaction, Ceramic, Pozzolanic activity
Abstract

The properties and hydration of blended cements containing from 8 to 40 % by mass of ceramic waste (CW) from different countries (Argentine and Czech Republic) are investigated. The mini slump, the heat released rate up to 48 h, the pozzolanic activity and the compressive strength at 2, 7 and 28 are determined. Hydration process is characterized by XRD analysis and the pore size refinement is accessed by MIP. Results show that both CWs increase the water demand with increasing the cement replacement level, and they possess pozzolanic activity after 7 days. At early age, the heat released and the compressive strength are lower than that of the Portland cement (PC) for all replacement levels. At 28 days, the pozzolanic reaction significantly improves the compressive strength. From XRD analysis, it is evident that CW reacts to form AFm phases (hemicarboaluminate at 7-28 and later transformed to monocarboaluminate) depending on the replacement level and CW used. CH peak reduction due to the pozzolanic reaction appears at 28 days. The reduction of porosity up to 16-24 % of CW replacement is in accordance with the compressive strength results.

Published
2015
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22. Potential use of Argentine kaolinite clays as pozzolanic material

Author

Alberto Nestor Scian, Alejandra Tironi, Edgardo F. Irassar, and Mónica Adriana Trezza

Subjects
Cement, Metallurgy, Geology, Pozzolan, INGENIERÍAS Y TECNOLOGÍAS, KAOLINITE, Cerámicos, Geochemistry and Petrology, CEMENT, Ingeniería de los Materiales, ARGENTINE CLAYS, Geotechnical engineering, POZZOLAN, Pozzolanic activity, Metakaolin
Abstract

Different Argentine kaolinitic clays were selected to study their potential pozzolanic activity. The incidence of several factors such as the origin of deposits (primary or sedimentary clays), mineralogical composition, and the order/disorder degree of kaolinite structure on the pozzolanic activity was analyzed. Five clays were characterized by chemical analysis, X-ray diffraction (XRD), Fourier transformed infra-red spectroscopy (FTIR), differential thermal analysis combined with thermo-gravimetric analysis (DTA/TG), and Scanning Electron Microscopy (SEM). The crystallinity of kaolinite in raw clays was estimated by five indexes: FWHM-001, FWHM-002, Hinckley Index (HI), and R2 on the XRD patterns, whereas the P0 index was determined on the FTIR spectra. Clays were calcined at 700 °C and ground until all mass passed through a 45 μm sieve. Pozzolanic activity was evaluated by the Frattini test and the strength activity index (SAI) at 7, 28 and 90 days using a blended cement containing 30% by weight of calcined clay. Complementary, the presence of remaining Ca(OH)2 in mortar was checked by XRD at 28 and 90 days. Results indicate that four blended cements presented a very good pozzolanic activity evaluated by the Frattini test at 7 and 28 days and they have a Different compressive strength with a SAI N 1 at 90 days. In these blended cements, the Ca(OH)2 released by cement hydrationwas consumed. Analyzing the incidence of factors on pozzolanic activity, it can be concluded that clays containingmore than 50% kaolinite provide enough amount of reactive material, and that the rate of the pozzolanic reaction is improved when the kaolinite mineral present in the clay has a disordered structure. Fil: Tironi, Alejandra. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingenieria de Olavarria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil; Argentina Fil: Trezza, Monica Adriana. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingenieria Olavarria; Argentina Fil: Scian, Alberto Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro Tecnológico de Recursos Minerales y Cerámica (i); Argentina Fil: Irassar, Edgardo Fabían. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina

Published
2014

23. Kaolinitic calcined clays - Portland cement system: Hydration and properties

Author

Edgardo F. Irassar, Viviana L. Bonavetti, Claudia C. Castellano, Alberto Nestor Scian, Mónica Adriana Trezza, and Alejandra Tironi

Subjects
Recubrimientos y Películas, CALCINED CLAY, media_common.quotation_subject, HYDRATION, Mineralogy, Blended cement, Building and Construction, Art, INGENIERÍAS Y TECNOLOGÍAS, KAOLINITE, law.invention, SORPTIVITY, Portland cement, law, Ingeniería de los Materiales, STRENGTH, General Materials Science, Humanities, Civil and Structural Engineering, media_common, BLENDED CEMENT
Abstract

This paper examines the influence of type of kaolinite in the raw clay on the performance of calcined clays as supplementary cementing materials. Two kaolinitic clays were characterized, calcined then ground and used as partial replacement of Portland cement at 15% and 30% by mass. The results show that both kaolinitic calcined clays are an effective pozzolan with different reaction rate. The reactivity is related to the specific surface area obtained after calcination and it depends on the structure of kaolinite. Raw clay containing disordered structure presents a very high pozzolanic activity allowing high replacement levels (30%) in blended cements. Fil: Tironi, Alejandra. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Castellano, Claudia Cristina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Bonavetti, Viviana Lidia. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Trezza, Mónica Adriana. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Scian, Alberto Nestor. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina Fil: Irassar, Edgardo Fabián. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina

Published
2014

24. Materiales cementicios de baja energía : Activación térmica de arcillas, relación entre estructura y actividad puzolánica

Author

Alejandra Tironi, Scian, Alberto Néstor, and Irassar, Edgardo F.

Subjects
cemento, Arcilla, ahorro de energía, actividad puzolánica, Química, Tratamiento Térmico, material cementante, Ciencias Exactas
Abstract

El objetivo general de la presente tesis es estudiar la relación entre la composición mineralógica y estructural de diferentes arcillas argentinas, el proceso de calcinación y la actividad puzolánica cuando se las utiliza como reemplazo parcial del cemento; con el fin de desarrollar materiales cementicios de baja energía y aceptables propiedades ingenieriles. Sus objetivos específicos: Seleccionar arcillas para su potencial uso como material puzolánico, previa activación térmica. - Caracterizar las arcillas seleccionadas, realizar la activación térmica, evaluar la actividad puzolánica y relacionar los resultados obtenidos. - Analizar los productos de hidratación formados y su efecto sobre las propiedades mecánicas cuando se realizan morteros de cemento Portland y arcillas calcinadas. - Determinar la influencia del tratamiento térmico en la actividad puzolánica de las arcillas. - Calcular el porcentaje de reemplazo en la formulación del cemento para obtener un material cementante con características equivalentes al CP. Estudiar los efectos producidos. - Estimar el ahorro energético generado por tonelada de material cementíceo producido, y la reducción de emisiones de CO2., Facultad de Ciencias Exactas

Published
2013
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25. Thermal activation of bentonites for their use as pozzolan

Author

Alberto Nestor Scian, Edgardo F. Irassar, Alejandra Tironi, and Mónica Adriana Trezza

Subjects
cement, cemento, bentonite, bentonitas, Puzolanas, Building and Construction, Civil and Structural Engineering, Pozzolans
Abstract

Se analiza la reactividad de dos bentonitas calcinadas, procedentes de diferentes regiones de Argentina para su utilización como adiciones puzolánicas al cemento Pórtland. A través de técnicas de: DRX, espectroscopia IR, ensayos de reactividad con Ca(OH)2. porosimetría por intrusión de mercurio y resistencia a la compresión; se relacionan los cambios estructurales producidos durante el tratamiento térmico con el comportamiento puzolánico. The reactivity of two calcined bentonites from different regions of Argentina for use as pozzolanic additions to Portland cement were analyzed. Through techniques of XRD, IR spectroscopy, tests of lime consumption and mechanical strength were relations structural changes, occurring during heat treatment, with pozzolanic behavior.

Published
2012

26. Blended Cements Elaborated with Kaolinitic Calcined Clays

Author

Mónica Adriana Trezza, Claudia C. Castellano, Alejandra Tironi, Edgardo F. Irassar, Alberto Nestor Scian, and Viviana L. Bonavetti

Subjects
Cement, Pozzolans, Absorption of water, Materials science, Sorptivity, Ingeniería en Materiales, Metallurgy, General Medicine, Clinker (cement), Metakaolinite, law.invention, Portland cement, Compressive strength, law, Kaolinitic Clays, Calcination, Composite material, Pozzolanic activity
Abstract

In the clinker production process, the main component of Portland cement (PC), large amount of CO2 are emitted into the atmosphere. The use of calcined kaolinitic clays as supplementary material of cement is an alternative to mitigate the environmental impact. In this paper, the influence of the replacement of PC by two calcined kaolinitic clays (15 and 30%), with high content of metakaolinite and different reactivity was studied. Calcined kaolinitic clays were characterized, the pozzolanic activity using Frattini test, the compressive strength, rate of water absorption (sorptivity), the assemblage of hydration products and the pore size distribution were determined at 28 days. The results show that the replacement of high percentage (30%) of very reactive clays improves the mechanical behavior and durable parameters compared with those obtained for plain PC., Centro de Tecnología de Recursos Minerales y Cerámica

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27. Thermal Treatment of Kaolin: Effect on the Pozzolanic Activity

Author

Alberto Nestor Scian, Edgardo F. Irassar, Mónica Adriana Trezza, and Alejandra Tironi

Subjects
Cement, metakaolin, Materials science, Waste management, kaolinite, Metallurgy, General Medicine, Thermal treatment, Residence time (fluid dynamics), law.invention, law, Kaolinite, Calcination, kaolin, Cementitious, Pozzolanic activity, Metakaolin, pozzolanas
Abstract

Thermally activated clays, especially kaolinitic clays, are today revaluated as a source of supplementary cementitious materials to reduce the CO2 emissions and energy consumption originated in cement production. In this work, the influence of different thermal treatments on the pozzolanic activity of raw kaolin with 98% kaolinite and ordered structure was studied. Results show that pozzolanic activity of calcined kaolin decays when using a thermal treatment at high temperatures (800 iC) and high periods of residence (30 minutes). Furthermore, low calcination temperature (700 iC) must be corresponding with a residence time that guarantees a high dehydroxylation percentage. Sample treated during 10 minutes (94%DH) was less reactive than the one treated during 30 minutes (96%DH). Results contribute to the industry purposes to reduce the energy consumption, the CO2 emission and to contribute with new alternatives of sustainable development.

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28. Incorporation of Calcined Clays in Mortars: Porous Structure and Compressive Strength

Author

Alberto Nestor Scian, Edgardo F. Irassar, Alejandra Tironi, and Mónica Adriana Trezza

Subjects
Cement, cement, Materials science, kaolinite, General Medicine, Pozzolan, law.invention, Compressive strength, pozzolana, law, Pozzolanic reaction, Kaolinite, Argentine clays, Calcination, Mortar, Composite material, Pozzolana
Abstract

During the last decades, there has been an increasing interest in the cement industry to incorporate pozzolanic materials to cement in order to reduce CO2 emissions, and increase the strength and durability of mortars and concretes. In this work, the potential use of two thermically activated kaolinitic clays as pozzolanic materials coming from different deposits of Argentina, is studied. Both Kaolinitic clays have different kaolinite content and a different order-disorder structure. After thermal treatment and grinding, their pozzolanic properties were studied on blended cement containing 30% of calcined clays. It was determined that mortars containing calcined clay with a higher percentage of kaolinite and certain disorder degree in its crystallinity previous to calcination, developed higher resistance to compression. This can be attributed to larger quantity of hydration products caused by the pozzolanic reaction, which also produces a better pore size arrangement. To conclude, when kaolinitic clays are used as pozzolana, kaolinitic percentage and structural disorder are variables to be taken into account.

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