Thermal treatment of kaolin: the effect of mineralogy on the pozzolanic activity

Kakali, G.; Perraki, T.; Tsivilis, S.; Badogiannis, Efstratios

doi:10.1016/s0169-1317(01)00040-0

Cited by 487 publications

(240 citation statements)

References 10 publications

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“…A argila se torna mais reativa quando conduz à perda da hidroxila, resultando em colapso e desarranjo da estrutura da argila. Segundo Kakali et al (2001), o desenvolvimento das propriedades pozolânicas de argilas calcinadas depende da natureza e da abundância do argilomineral, das condições de calcinação e da finura do produto final. As propriedades pozolânicas são desenvolvidas por calcinação a cerca de 500 °C, cujas temperaturas ótimas são entre 700 e 900 °C (Santos, 1992).…”

Section: Introductionunclassified

Potencialidades de um caulim calcinado como material de substituição parcial do cimento portland em argamassas

Oliveira

Barbosa

2006

Rev. bras. eng. agríc. ambient.

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RESUMOA utilização de argilas calcinadas na forma de metacaulinita, como material pozolânico para argamassas e concretos, tem recebido atenção considerável nos últimos anos. Este trabalho objetivou avaliar o desempenho mecânico de argamassas, nas quais foi utilizado um caulim calcinado proveniente do Estado da Paraíba, como material de substituição parcial do cimento Portland. Utilizaram-se duas finuras do caulim: passando nas peneiras ABNT 200 (0,074 mm) e 325 (0,044 mm) e calcinados nas temperaturas de 700, 800 e 900 °C pelo tempo de 2 h. As amostras foram caracterizadas através de análise química, análise térmica diferencial, difração de raios-X e área específica. Obteve-se o índice de atividade pozolânica com a cal e o cimento Portland. O percentual de substituição adotado foi de 0, 10, 20, 30 e 40%. A relação aglomerante: areia foi de 1:1,5 e a relação água/aglomerante fixada igual 0,4. O efeito da substituição parcial do cimento na argamassa foi avaliado através da resistência à compressão simples, nas idades de 7, 28 e 90 dias. As argamassas estudadas apresentaram resistência superior em relação à da referência, até o nível de 30% de substituição.Palavras-chave: pozolana, argila calcinada, atividade pozolânica Potentialities of a calcined kaolin as material of partial replacement of portland cement in mortars ABSTRACTThe use of burnt clays, in the metakaolin form, as pozzolanic material for mortars and concretes has received a remarkable attention in the last years. This paper aimed to evaluate the mechanical property of mortars, in which a calcined kaolin originating from the State of Paraiba, was used as partial cement replacement material. Two finess of the kaolin were used: ABNT 200 (0.074 mm) and 325 (0.044 mm) and burnt at temperatures of 700, 800 and 900 °C for a period of 2 h. Both materials were characterized by chemical analysis, differential thermal analysis, X-ray diffraction, specific area tests. The pozolanic activity index was obtanied using lime and cement Portland. The amounts of replacement were 10, 20, 30 and 40%, besides the reference mortar. The binder: sand ratio was 1:1.5 and the water/binder ratio was constant and equal to 0.4. The effect of partial substitution of cement in mortar was evaluated through compressive strength at 7, 28 and 90 days. Mortars with kaolin presented superior strength comparing to reference mortar, up to the level of 30% of substitution.

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Section: Introductionunclassified

Potencialidades de um caulim calcinado como material de substituição parcial do cimento portland em argamassas

Oliveira

Barbosa

2006

Rev. bras. eng. agríc. ambient.

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“…When the inflection point occurs in the DTA graph, it means that there is a dehydration event, decomposition, or change in the crystal structure (phase conversion) of the mineral at that point. It was reported by many scientists that kaolinite has endothermic reaction around 500°C, which is related to the conversion from kaolin to metakaolin (Ilić et al 2010;Vizcayno et al 2010;Kakali et al 2001;Rabehi et al 2014). According to Fig.…”

Section: Heat Treatmentmentioning

confidence: 99%

Evaluation of Pozzolanic Activity for Effective Utilization of Dredged Sea Soil

Moon

Kim

Lee

et al. 2017

Int J Concr Struct Mater

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In this work, pozzolanic activities of dredged sea soil from two different sources (South Harbor at Busan and Jangsaengpo Harbor at Ulsan) in Republic of Korea were investigated. Dredged sea soil used for this work has passed through a patented purification process, and particle size distribution, X-ray fluorescence, X-ray diffraction, and thermogravimetry/differential thermal analysis (TG/DTA) were utilized to understand its chemical and mineralogical characteristics. Temperature for heat treatment of dredged sea soil were determined using data obtained from TG/DTA, and pozzolanic activities of dredged sea soil samples were investigated by tracking the amount of calcium hydroxide spent for pozzolanic reaction as well as by monitoring the enhancement on 28 day compressive strength. According to the results, dredged sea soil samples from Jangsaengpo Harbor, which contains some amount of silt sized minerals, showed clear pozzolanic activity after heat treatment at 500°C. However, dredged sea soil samples from South Harbor did not exhibit strong pozzolanic reaction due to its larger particle size. At least, it was found that dredged sea soil samples have possibility to be used as a pozzolanic material after proper heat treatment if the size distribution of the particle contains certain amount of silt.

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“…Pozzolanic activation of kaolinite and sepiolite was accomplished, according to literature [23][24][25][26][27][28], heating kaolin samples at 700°C to obtain metakaolin (MK) and the samples of sepiolite (SP) at 830°C. Results were checked through TG-DTA at static air atmosphere and XRD.…”

Section: Materials Testing Equipment and Experimental Techniquesmentioning

confidence: 99%

Assessment of phase formation in lime-based mortars with added metakaolin, Portland cement and sepiolite, for grouting of historic masonry

Aguilar¹,

Olivares

2010

Cement and Concrete Research

107

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Lime-based mortars containing pozzolanic additions of metakaolin, sepiolite and white Portland cement are studied in order to determine their performance as historic masonry conservation mortars. Hydration products on metakaolin-lime blended mortars include stable and metastable phases. The presence of such products has been studied by means of DTA and XRD analysis, concluding that the selection between them is mainly related with the water-lime ratio. Sepiolite addition to metakaolin-lime mortars has shown to inhibit C 4 AH 13 formation. Therefore, the influence of phase distribution on the mechanical resistance is considered. Finally, compounds production on blended lime-white Portland cement was compared to natural hydraulic lime ones, and as a result, no remarkable differences appeared, apart from traces of possible cement Portland addition to the latter, usually not mentioned in the nominal composition supplied by the manufacturers of lime binders.

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Thermal treatment of kaolin: the effect of mineralogy on the pozzolanic activity

Cited by 487 publications

References 10 publications

Potencialidades de um caulim calcinado como material de substituição parcial do cimento portland em argamassas

Potencialidades de um caulim calcinado como material de substituição parcial do cimento portland em argamassas

Evaluation of Pozzolanic Activity for Effective Utilization of Dredged Sea Soil

Assessment of phase formation in lime-based mortars with added metakaolin, Portland cement and sepiolite, for grouting of historic masonry

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