Academic literature on the topic 'Pozzolanic Activity'

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Journal articles on the topic "Pozzolanic Activity"

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Santana, Juan J., Natalia Rodríguez-Brito, Concepción Blanco-Peñalver, Vicente F. Mena, and Ricardo M. Souto. "Durability of Reinforced Concrete with Additions of Natural Pozzolans of Volcanic Origin." Materials 15, no. 23 (November 24, 2022): 8352. http://dx.doi.org/10.3390/ma15238352.

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In this work, the properties of concrete modified with dosages of natural pozzolans (NP) in substitution of cement or superfine aggregates were evaluated. Proportions of 20/80 pozzolan/cement or pozzolan/superfine aggregates were selected for the additions of quarry and tuff pozzolans. Pozzolanic activity, durability, compressive strength, characteristic resistance, settling consistency, density, electrical resistivity, depth of water penetration, accessible porosity, and carbonation and chloride penetration were determined for the resulting concrete mixtures, and they were subsequently compared to the values obtained for the reference concrete batches without additions. The results of the cementitious mixtures supplemented with tuff (PZT) and quarry (PZQ) pozzolans, expressed in mmol/L, are consistent with the pozzolanism test, with [Ca(OH)2]/[OH−] ratios at 7 days are 6.03/60.19 for PZQ and 1.78/92.78 PZT. In addition to the pozzolanic activity at these dosages, the characteristic resistance and durability parameters required by EHE-08 were verified. Particular attention was given to the determination of the diffusion of chloride ions, introducing an instrumental modification of the accelerated integral method. The modification provides values of diffusion coefficients similar to those obtained by the other methods with the advantage of greater stability and quality of the measurement.
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2

Shi, Caijun. "An overview on the activation of reactivity of natural pozzolans." Canadian Journal of Civil Engineering 28, no. 5 (October 1, 2001): 778–86. http://dx.doi.org/10.1139/l01-041.

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Natural pozzolan is one of the oldest construction materials. Lime-pozzolan cements have been used for several thousands of years and have an excellent reputation for their durability. Pozzolans are being widely used as a cement replacement in Portland cement concrete. The use of pozzolans has the advantage of lower costs and better durability, but the disadvantage of a longer setting time and a slower early strength development. Different techniques have been tried to increase the reactivity of natural pozzolans to overcome these disadvantages. This paper has reviewed various methods used to activate the pozzolanic activity of natural pozzolans. All activation methods can be classified into three catalogues: thermal, mechanical, and chemical activation. A comparison based on strength–cost relationship indicates that the chemical activation method is the most effective and cheapest one.Key words: activation, reactivity, natural pozzolans, pozzolanic reaction, calcination, elevated temperature curing, chemical activators, strength, cost.
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Villar-Cociña, Ernesto, Moisés Frías, Holmer Savastano, Loic Rodier, María Isabel Sánchez de Rojas, Isabel Fuencisla Sáez del Bosque, and César Medina. "Quantitative Comparison of Binary Mix of Agro-Industrial Pozzolanic Additions for Elaborating Ternary Cements: Kinetic Parameters." Materials 14, no. 11 (May 29, 2021): 2944. http://dx.doi.org/10.3390/ma14112944.

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In this research work, the quantitative characterization of a binary blend comprised of two pozzolans (sugar cane straw (SCSA)–sugar cane bagasse ashes (SCBA), bamboo leaf ash (BLAsh)–SCBA and paper sludge (PS)–fly ash (FA)) taking into account the calculated values of the kinetic parameters of the reaction in the pozzolan/calcium hydroxide system is shown. The paper shows the most significant and important results obtained by the authors in the quantitative assessment (calculation of kinetic parameters) of the pozzolanic reaction of different mixtures of pozzolanic materials that are residues from agriculture or industrial processes. This allows a direct and rigorous comparison of the pozzolanic activity of the binary combinations of materials. The values of the kinetic parameters (reaction rate constant or activation free energy) constitute a very precise quantitative index of the pozzolanic activity of the binary combinations of materials, which is very useful for its employment in the elaboration of ternary cements. This paper shows that the binary blends 1SCBA60Blash40, 1SCBA50Blash50, 1SCBA70Blash30 have a very high pozzolanic reactivity followed by PSLSFA, 2SCBA50SCSA50, PSISFA and SCWI.
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Juimo Tchamdjou, Willy Hermann, Sophie Grigoletto, Frédéric Michel, Luc Courard, Toufik Cherradi, and Moulay Larbi Abidi. "Effects of Various Amounts of Natural Pozzolans from Volcanic Scoria on Performance of Portland Cement Mortars." International Journal of Engineering Research in Africa 32 (September 2017): 36–52. http://dx.doi.org/10.4028/www.scientific.net/jera.32.36.

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The aim of this paper is to assess the possibility of using natural pozzolans (NPs) from Cameroonian volcanic scoria as supplementary cementitious materials (SCMs) in the production of Portland cement mortars. Four natural pozzolans (Black Natural Pozzolan: BNP, Dark-Red Natural Pozzolan: DRNP, Red Natural Pozzolan: RNP and Yellow Natural Pozzolan: YNP) with 3600, 4500, 4700 and 5200 cm2/g Blaine fineness respectively were produced from different colors (Black, Dark red, Red and Yellow) volcanic scoria in a laboratory mill. Natural pozzolans were characterized with regard to particle size distribution, particle shape, electrical conductivity, X-ray fluorescence (XRF) and X-ray diffraction (XRD). The calcium hydroxide consumption by NPs was assessed firstly by electrical conductivity measurements of calcium hydroxide/NPs suspensions with calcium hydroxide excess. Evidence of pozzolanic reactivity of NPs is revealed in hydrated lime pastes, and low reactivity was observed in aqueous suspensions. The effects of 15, 25, and 35 wt.% of NPs as cement substitution on the properties of Portland cement mortars were investigated. Different properties were studied such as setting time, consistency, mechanical strength, pozzolanic activity, absorption by capillarity and resistance to carbonation. The reactivity of NPs was also assessed by means of the mechanical strength development of mortars. The results obtained show that pozzolanic and hydraulic reactions take place in OPC systems. The correlation between mechanical strengths and physical properties of NPs has been established. The study concludes that using DRNP and RNP at 15 wt. % cement replacement can ameliorate globally the performance of mortar. Using all NPs at 35 wt. % has negative effect on the fundamental properties of cementitious mortars.
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Liguori, Barbara, Paolo Aprea, Bruno de Gennaro, Fabio Iucolano, Abner Colella, and Domenico Caputo. "Pozzolanic Activity of Zeolites: The Role of Si/Al Ratio." Materials 12, no. 24 (December 17, 2019): 4231. http://dx.doi.org/10.3390/ma12244231.

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A great challenge of research is the utilization of natural or synthetic zeolites, in place of natural pozzolans, for manufacturing blended cements. The difficulties of interpretation of the pozzolanic behavior of natural zeolite-rich materials and the role played by their nature and composition can be overcome by studying more simple systems, such as pure synthetic zeolites. This study aims at investigating the pozzolanic ability of isostructural zeolites with different framework compositions, such as three sodium zeolites of the faujasite (FAU) framework type: LSX, X, and Y. The pozzolanic activity has been estimated by thermogravimetry and X-ray diffraction analysis. The overall outcome of the investigation is that the zeolite structure affects its pozzolanic activity, as zeolites with similar framework densities exhibit distinct abilities to fix lime. Moreover, the framework composition is effective either from a kinetic point of view or on the total amount of fixed lime. Zeolite X appears to possess the best average features.
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6

Záleská, Martina, Milena Pavlíková, and Zbyšek Pavlík. "Classification of a-SiO2 Rich Materials." Materials Science Forum 824 (July 2015): 33–38. http://dx.doi.org/10.4028/www.scientific.net/msf.824.33.

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The powder materials containing active SiO2, which are used as pozzolanic active materials in cement mixtures, can be classified in consideration of their pozzolana activity, particle size or reactivity. In this paper, several types of metakaoline are studied using Frattini and modified Chapelle test for pozzolanic activity determination. The particle size analysis is measured using the laser diffraction analyser and the differences in the chemical composition are characterized by FTIR spectroscopy. The obtained data show influence of particle size and chemical composition of tested powders on their pozzolanic activity, which corresponds with the results of Frattini and modified Chapelle test.
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Sierra, Oscar M., Jordi Payá, José Monzó, María V. Borrachero, Lourdes Soriano, and Javier Quiñonez. "Characterization and Reactivity of Natural Pozzolans from Guatemala." Applied Sciences 12, no. 21 (November 3, 2022): 11145. http://dx.doi.org/10.3390/app122111145.

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The possibility of using pozzolanic materials as a partial substitute for Portland cement (PC) to develop mortars and concretes promotes environmental and economic benefits. The present paper includes an in-depth investigation into the characterization of natural pozzolans from Guatemala for the valorization of these materials. An exhaustive physico-chemical characterization of the starting materials was first carried out. Second, an analysis of the pozzolanic reactivity of both pozzolans was performed using an evolution test of the pH and electrical conductivity measurements and a Frattini test. Finally, pastes and mortars were manufactured with pozzolans T and R as a substitute for PC. The results of the pH and electrical conductivity measurements confirmed that natural pozzolans can be classified as low-reactivity. The Frattini test and the thermogravimetric analysis confirmed the pozzolanic behavior of natural pozzolans at 28 curing days. In the cement pastes, lime fixation was positive for a long curing period, which demonstrated that these pozzolans had medium–long-term pozzolanic activity, similar to fly ash (FA). The results were confirmed by mechanical assays. The mortars with 15%, 25%, and 35% substitutions of cement for pozzolans had strength gain percentages of around 13–15% at 90 curing days.
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Pontes, Jorge, António Santos Silva, and Paulina Faria. "Evaluation of Pozzolanic Reactivity of Artificial Pozzolans." Materials Science Forum 730-732 (November 2012): 433–38. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.433.

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Pozzolanicity is a very interesting issue regarding building materials, as a way to enhance mortars and concrete durability. This property results from the reaction between calcium hydroxide and silica and alumina based materials. Different types of natural and artificial pozzolans show pozzolanic activities that differ depending on the materials characteristics. Therefore, the study of this property, namely its reactivity with calcium hydroxide, reveals itself to be important in the selection of the type and content of these materials. This paper presents the results of several pozzolanic reactivity methods, applied to different pozzolanic materials. The selected pozzolanic methods include Chapelle method, Fratinni method and Strength Activity Index. Those tests have been applied to evaluate the reactivity of various kinds of artificial pozzolans. The correlation between the test methods are presented and discussed.
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Pavlíková, Milena, Pavla Rovnaníková, Martina Záleská, and Zbyšek Pavlík. "Diatomaceous Earth—Lightweight Pozzolanic Admixtures for Repair Mortars—Complex Chemical and Physical Assessment." Materials 15, no. 19 (October 3, 2022): 6881. http://dx.doi.org/10.3390/ma15196881.

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The presented research is focused on the complex assessment of three different types of diatomaceous earth and evaluation of their ability for application as pozzolana active admixtures applicable in the concrete industry and the production of repair mortars applicable for historical masonry. The comprehensive experimental campaign comprised chemical, mineralogical, microstructural, and physical testing of raw materials, followed by the analyses and characterization of pozzolanic activity, rheology and heat evolution of fresh blended pastes, and testing of macrostructural and mechanical parameters of the hardened 28-days and 90-days samples. The obtained results gave evidence of the different behavior of researched diatomaceous earth when mixed with water and Portland cement. The differences in heat evolution, initial and final setting time, porosity, density, and mechanical parameters were identified based on chemical and phase composition, particle size, specific surface, and morphology of diatomaceous particles. Nevertheless, the researched mineral admixtures yielded a high strength activity index (92.9% to 113.6%), evinced their pozzolanic activity. Three fundamental factors were identified that affect diatomaceous earth’s contribution to the mechanical strength of cement blends. These are the filler effect, the pertinent acceleration of OPC hydration, and the pozzolanic reaction of diatomite with Portland cement hydrates. The optimum replacement level of ordinary Portland cement by diatomaceous earth to give maximum long-term strength enhancement is about 10 wt.%., but it might be further enhanced based on the properties of pozzolan.
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Bonavetti, V. L., V. F. Rahhal, F. Locati, E. F. Irassar, S. Marfil, and P. Maiza. "Pozzolanic activity of argentine vitreous breccia containing mordenite." Materiales de Construcción 70, no. 337 (February 17, 2020): 208. http://dx.doi.org/10.3989/mc.2020.04019.

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A vitreous breccia with variable amount of mordenite was studied for its use as pozzolan. The raw material was characterized by optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), and the zeolite content was estimated by the methylene blue staining technique. After being ground, physical characteristics, cation exchange capacity (CEC), pozzolanicity, and the compressive strength activity index (SAI) were determined. The staining technique and the CEC measurement were used to evaluate the average content of zeolite. The vitreous breccia has pozzolanic activity after 7 days, the water demand increases slightly, and its addition stimulates the early hydration of portland cement. At later ages, the pozzolanic reaction around the grains, as revealed by SEM studies, improves the compressive strength of blended cements having a SAI > 0.85 at 28 days.
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Dissertations / Theses on the topic "Pozzolanic Activity"

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Duerden, Susan Lynn. "PFA morphology, pozzolanic activity and contribution to concrete performance." Thesis, University of Dundee, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327806.

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Adams, Andrew. "An assessment of the effects of pozzolanic activity on the behaviour of fly ash." Thesis, Durham University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342795.

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Hansen, Débora Magali. "Avaliação das propriedades pozolânicas de um resíduo de cerâmica vermelha para emprego como material cimentício suplementar." Universidade do Vale do Rio dos Sinos, 2016. http://www.repositorio.jesuita.org.br/handle/UNISINOS/5397.

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Made available in DSpace on 2016-06-15T15:50:42Z (GMT). No. of bitstreams: 1 DÉBORA MAGALI HANSEN_.pdf: 2330600 bytes, checksum: 74a7605994355dc5762f8c364bddf4c9 (MD5) Previous issue date: 2016-03-30
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares
A destinação final ambientalmente adequada para os resíduos sólidos industriais é uma problemática que veio ganhando maior importância ao longo dos anos. O setor da construção civil consome grandes quantidades de insumos, gerando paralelamente grandes quantidades de resíduos. Quando o assunto é reciclagem de resíduos industriais, o setor da construção civil exerce um papel importante, reciclando resíduos de diversos setores da economia. Tendo em vista a existência do polo cerâmico no Rio Grande do Sul, e totalidade de resíduos de cerâmica vermelha (RCV) resultante desse polo, buscou-se através deste estudo, verificar qual é o percentual de geração de RCV em uma empresa específica, devido a grande variabilidade dos dados apresentados pela literatura. E em paralelo buscou-se avaliar o potencial pozolânico do RCV e comparar o seu desempenho com o metacaulim, material já consagrado como pozolana. Os aglomerantes (cimento CP II-F-32, Ca(OH)2 – P.A., CH-I) e os materiais pozolânicos (RCV e metacaulim) empregados na pesquisa foram caracterizados quimicamente por ensaios de fluorescência de raios X (FRX) e Perda ao Fogo (PF), mineralogicamente por ensaios de difração de raios X (DRX) e fisicamente por ensaios de, granulometria a laser, massa específica e área superficial específica (BET). Além disso, o RCV e o metacaulim foram submetidos a ensaios para determinação do teor de umidade e finura. Para avaliar a atividade pozolânica do RCV e comparar seu desempenho ao metacaulim foram realizados ensaios de condutividade elétrica, termogravimetria e ensaios de resistência à compressão, orientados pelas NBR 5752:2014, NBR 5751:2015 e NBR 15894:2010. Mediante os resultados obtidos, verificou-se que o percentual de geração de RCV na empresa objeto de estudo, com os ensaios de caracterização foi possível verificar que o RCV atende aos requisitos químicos estabelecidos pela NBR 12653:2014. O procedimento de moagem conferiu ao RCV uma granulometria adequada para uso como pozolona. Quanto a atividade pozolânica, verificou-se que o RCV atendeu ao requisito da NBR 12653:2014, no que diz respeito à resistência com o aglomerante Ca(OH)2 P.A., já quando ensaiado com o aglomerante CH-I, o RCV apresentou resistência à compressão consideravelmente superior ao metacaulim. Já nas argamassas moldadas com cimento, o RCV não atingiu o índice de atividade pozolânica (IAP) exigido na NBR 12653:2014, impedindo sua classificação como material pozolânico. Nas argamassas ensaiadas sob as prescrições da NBR 15894:2010, contendo 15% de substituição do cimento pelo RCV, os resultados de resistência à compressão não apresentaram diferenças significativas em relação às argamassas referência, apontando indícios de melhor desempenho em menores teores de substituição. As análises térmicas evidenciaram o consumo de Ca(OH)2 das pastas. As pastas formuladas com 25% de substituição do cimento por metacaulim apresentaram maior consumo de Ca(OH)2 em relação as pastas formuladas com 25% de RCV, evidenciando a atividade pozolânica dos materiais.
The final destination environmentally suitable for industrial solid waste is a problem that came gaining more importance over the years. The construction industry consumes large amounts of supplies, generating parallel large quantities of waste. When it comes to recycling of industrial waste, the construction sector plays an important role, recycling waste from various sectors of the economy. Considering the existence of the ceramic polo at the Rio Grande do Sul, and all red ceramic waste (RCV) resulting from this pole, we sought through this study, find what is the percentage of RCV generation in a specific company due the great variability of the data presented in the literature. And in parallel we sought to evaluate the potential of pozzolan RCV and compare their performance with metakaolin, material already recognized as pozzolan. The binder (cement CP II-F-32, Ca(OH)2 – P.A., CH-I) and pozzolanic materials (RCV and metakaolin) employed in the study were chemically characterized by X-ray fluorescence assays (XRF) and Loss Fire (PF), mineralogically by testing X-ray diffraction (XRD) and physically by tests of laser granulometry, specific gravity and specific surface area (BET). Furthermore, the RCV and metakaolin were subjected to tests for determination of humidity content and fineness. To evaluate the pozzolanic activity of the RCV and compare its performance to metakaolin were performed electrical conductivity tests, thermogravimetry and compressive strength tests, guided by the NBR 5752:2014, NBR 5751:2015 and NBR 15894:2010. From the results obtained, found to the percentage of RCV generation in study subject company with the characterization tests it was verified that the RCV meets chemical requirements of the NBR 12653:2014. The grinding procedure gave the RCV adequate particle size for use as pozolona. As the pozzolanic activity, it was found that the RCV met requirement the NBR 12653:2014 with regard to resistance to Ca(OH)2 P.A. agglomerating, since when tested with CH-I agglomerating, the RCV showed compression resistance the considerably higher than metakaolin. Already in the cast with cement mortar, the RCV has not reached the pozzolanic activity index (IAP) required in NBR 12653:2014 preventing classification as pozzolanic material. In mortars tested under the requirements of NBR 15894:2010, containing 15% replacement of cement by RCV, the compressive strength results showed no significant differences from the reference mortar, indicating better performance indications in lower replacement levels. The thermal analysis showed the consumption of Ca(OH)2 pastes. The pastes formulated with 25% of the cement replaced by metakaolin showed increased consumption of Ca(OH)2 relative pastes formulated with 25% RCV, showing the pozzolanic activity of the materials.
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Uzal, Burak. "Properties And Hydration Of Cementitious Systems Containing Low, Moderate And High Amounts Of Natural Zeolites." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608974/index.pdf.

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The extent of the benefits provided by use of SCMs in cementitious systems increases as their percentage amounts in total binder increases. However, the proportion of SCMs in cementitious systems is limited, especially for natural pozzolans, by some factors such as increase in water requirement and decrease in rate of strength development. Therefore investigations are needed to increase the amount of natural pozzolans in blended cements or in concrete as much as possible without decreasing their performance. This aim requires studies on cementitious systems with more reactive natural pozzolans than widely-used ones. The objective of the study was to investigate the pozzolanic activity of natural zeolites (clinoptilolite) from two localities in Turkey, and properties of cementitious systems containing low (15%), moderate (35%) and high (55%) amount of them. The study covers characterization of the natural zeolites used, evaluation of their pozzolanic activity in comparison with some popular mineral admixtures, and properties of pastes, mortars, and concrete mixtures containing low, moderate, and high amounts of natural zeolites. Reactivity of the natural zeolites with Ca(OH)2 was found to be higher than those of the fly ash and the non-zeolitic pozzolan, but lower than that of the silica fume. Natural zeolite blended cements were characterized with the following highlighted properties
faster setting than portland cement, low amounts of Ca(OH)2 and capillary pores larger than 50 nm in hardened pastes, relatively dense microstructure of hardened paste than portland cement, more compatibility with melamine-based superplasticizer than being with naphthalene-based one, and excellent compressive strength performance. Concrete mixtures containing natural zeolites as partial replacement for portland cement were characterized with the following properties
7-day compressive strength of ~25 MPa and 28-day strength of 45-50 MPa with only 180 kg/m3 portland cement and 220 kg/m3 zeolite dosages (55% replacement), comparable modulus of elasticity with plain portland cement concrete, &ldquo
low&rdquo
and &ldquo
very low&rdquo
chloride-ion penetrability for low and large levels of replacement, respectively.
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Tashima, Mauro Mitsuuchi [UNESP]. "Cinza de casca de arroz altamente reativa: método de produção, caracterização físico-química e comportamento em matrizes de cimento Portland." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/91490.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Universidade Politecnica de Valencia- Espanha
O presente trabalho apresenta um método de produção de cinza de casca de arroz (CCA) altamente reativa e de coloração clara, bem como o seu comportamento em matrizes de cimento Portland com o intuito de avaliar a atividade pozolânica da CCA. O trabalho está dividido em quatro etapas, a saber: construção de um forno e produção da cinza de casca de arroz, caracterização físico-química da CCA, verificação da atividade pozolânica do material através de métodos instrumentais e, finalmente, ensaios mecânicos em argamassas de cimento Portland. O forno utilizado para a produção da cinza de casca de arroz não apresenta controle de temperatura e, o tempo de queima é bastante longo, aproximadamente 36 horas. Neste método obtém-se cerca de 1,5Kg de cinza por processo de queima. A cinza obtida apresenta uma coloração clara e o seu caráter amorfo foi determinado através de diferentes métodos: difração de Raio-X, determinação do teor de sílica amorfa, análise termogravimétrica, Microscopia Eletrônica de Varredura (MEV) e ensaios mecânicos em argamassas de cimento Portland. O programa experimental também abrange estudos de variação da finura da CCA e estudos com diferentes porcentagens, em substituição ao cimento Portland. Os resultados obtidos foram comparados...
This research show a method of production white amorphous Rice Husk Ash (RHA), therefore, the behaviour of RHA in Portland cement matrix to evaluate the pozzolanic activity of this material. The research can be shared in four steps, to know: construction of an oven and production of rice husk ash, physical-chemical analysis of the rice husk ash, evaluation of pozzolanic activity of the pozzolan though instrumental analysis and, finally, mechanical properties of Portland cement mortars. The oven used for production of rice husk ash didn't have a control of temperature and, the time of burning is so longer, approximately 36 hours. In this method is obtained for about 1,5Kg of ash. The obtained ash has white colour and its amorphous phase were determined though different methods: X-ray diffractometry, determination of amorphous silica, Termogravimetric Analysis (TA), scanning electron microscopy (SEM) and mechanical properties of Portland cement mortars. Besides that, the experimental procedure involves studies on fineness variation of rice husk ash and different degrees of Portland cement substitution. The obtained results were compared with silica fume, because this is the most similar pozzolanic material with rice husk ash. The RHA produced under this method can be used... (Complete abstract click electronic access below)
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Tashima, Mauro Mitsuuchi. "Cinza de casca de arroz altamente reativa : método de produção, caracterização físico-química e comportamento em matrizes de cimento Portland /." Ilha Solteira : [s.n.], 2006. http://hdl.handle.net/11449/91490.

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Orientador: Jorge Luis Akasaki
Banca: Marco Antonio Moraes Alcantara
Banca: Antônio Alberto Nepomuceno
Resumo: O presente trabalho apresenta um método de produção de cinza de casca de arroz (CCA) altamente reativa e de coloração clara, bem como o seu comportamento em matrizes de cimento Portland com o intuito de avaliar a atividade pozolânica da CCA. O trabalho está dividido em quatro etapas, a saber: construção de um forno e produção da cinza de casca de arroz, caracterização físico-química da CCA, verificação da atividade pozolânica do material através de métodos instrumentais e, finalmente, ensaios mecânicos em argamassas de cimento Portland. O forno utilizado para a produção da cinza de casca de arroz não apresenta controle de temperatura e, o tempo de queima é bastante longo, aproximadamente 36 horas. Neste método obtém-se cerca de 1,5Kg de cinza por processo de queima. A cinza obtida apresenta uma coloração clara e o seu caráter amorfo foi determinado através de diferentes métodos: difração de Raio-X, determinação do teor de sílica amorfa, análise termogravimétrica, Microscopia Eletrônica de Varredura (MEV) e ensaios mecânicos em argamassas de cimento Portland. O programa experimental também abrange estudos de variação da finura da CCA e estudos com diferentes porcentagens, em substituição ao cimento Portland. Os resultados obtidos foram comparados... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This research show a method of production white amorphous Rice Husk Ash (RHA), therefore, the behaviour of RHA in Portland cement matrix to evaluate the pozzolanic activity of this material. The research can be shared in four steps, to know: construction of an oven and production of rice husk ash, physical-chemical analysis of the rice husk ash, evaluation of pozzolanic activity of the pozzolan though instrumental analysis and, finally, mechanical properties of Portland cement mortars. The oven used for production of rice husk ash didn't have a control of temperature and, the time of burning is so longer, approximately 36 hours. In this method is obtained for about 1,5Kg of ash. The obtained ash has white colour and its amorphous phase were determined though different methods: X-ray diffractometry, determination of amorphous silica, Termogravimetric Analysis (TA), scanning electron microscopy (SEM) and mechanical properties of Portland cement mortars. Besides that, the experimental procedure involves studies on fineness variation of rice husk ash and different degrees of Portland cement substitution. The obtained results were compared with silica fume, because this is the most similar pozzolanic material with rice husk ash. The RHA produced under this method can be used... (Complete abstract click electronic access below)
Mestre
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Soukupová, Eva. "Omítky modifikované příměsí pálených jílů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-234557.

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The doctoral thesis deals with the reactivity of burnt clays in connection with modified lime mortars. The theoretical part of the doctoral thesis provides an overview of the properties of lime mortars, their quality and ways of their degradation. The different types of burnt clays (brick powder, bentonites and burnt clay shale), their origin, properties and factors affecting their reactivity and methods of its evaluation are stated. The properties and reactivity of burnt clays are evaluated on the basis of determination of pozzolanic activity, mineralogical and chemical composition, surface area, density, content of the amorphous phase and granulometry in the experimental part of the doctoral thesis. The compositions of lime mortars containing burnt clays and evaluation of an impact of burnt clay on the properties of mortars in the fresh and hardened state are given. Consistency, bulk density, workability and air content of mortars in the fresh state are evaluated. Strength characteristics depending on the time, water absorbability, porosity, capillary attraction, adhesion, coefficient of diffusion resistance, frost resistance, shrinkage, mineralogical composition and microstructure of mortars in the hardened state are evaluated. Attention is also paid to the influence of the cellulose ether addition into the modified lime mortars.
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Rodier, Loïc. "Matériaux de construction en zone tropicale humide : Potentialités de sous-produits ou de matériaux naturels locaux en substitution ou addition à la matrice cimentaire." Thesis, Antilles-Guyane, 2014. http://www.theses.fr/2014AGUY0804/document.

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L’incorporation de sous-produits agricoles ou de matériaux naturels dans la matrice cimentaire confère des propriétés intéressantes aux composites élaborés. L’objectif de cette thèse est d’élaborer un matériau pouvant répondre aux exigences mécaniques, thermiques et de durabilité des matériaux de construction en zone tropicale humide. Dans un premier temps, l’activité pouzzolanique d’une pouzzolane naturelle, de cendres de tronc de bambou et de cendres de bagasse de canne à sucre ont été évaluées. L’influence de leur incorporation a été ensuite étudiée sur les propriétés mécaniques et la durabilité des mortiers exposés à des ions chlorures et sulfates. Dans un second temps, l’influence de l’ajout de fibres de bagasse sur les propriétés thermiques et mécaniques des composites a été étudiée en fonction de différents paramètres (teneur en fibres, environnement de vieillissement, type de matrice cimentaire).Les résultats obtenus ont permis de montrer que les matériaux étudiés possèdent une activité pouzzolanique et qu’il est possible de les incorporer au ciment afin de lutter contre la corrosion. De plus, les composites élaborés avec des fibres de bagasse sont plus isolants que ceux élaborés sans fibres. Cependant, du point de vue des propriétés mécaniques, l’incorporation de fibres de bagasse diminue les contraintes à la flexion des composites
The incorporation of crop wastes or natural materials in the cement matrix confers interesting properties to composites prepared. The aim of this thesis is to develop a material that can reach the mechanical, thermal and durability requirements for building materials in the humid tropical zone. Firstly, pozzolanic activity of a natural pozzolan, bamboo stem and sugar cane bagasse ashes has been determined. Influence of their incorporation on mechanical properties and durability of mortars exposed to chloride and sulphate ions was studied. Secondly, influence of addition of bagasse fibers on thermal and mechanical properties of composites was studied as a function of various parameters (fibers content, curing, type of cement matrix).These results has shown that the materials studied have pozzolanic activity and it is possible to incorporate them into the cement to fight against corrosion. Moreover, composites elaborated with bagasse fibers are more insulating than those elaborated without fibers. However, from the viewpoint of mechanical properties, incorporation of bagasse fibers decreases flexural strength of composites in the present work and under the conditions producing procedures that were adopted
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Rovnaníková, Markéta. "Studium a modelování karbonatace betonu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2012. http://www.nusl.cz/ntk/nusl-233351.

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The corrosion of steel reinforcement is probably the most frequent type of degradation of reinforced concrete structures. Reinforcing bars are protected from corrosion by a thin iron oxide layer which is formed on their surface due to a high alkalinity of the surrounding concrete. Corrosion may start when this layer is destroyed (i) either by chloride ion penetration (when the concentration of dissolved chloride at the depth of the reinforcing steel exceeds a critical value) or (ii) by a reduction in the pH value of pore solution to values below 9.5. Such a reduction in alkalinity is the result of carbonation of the Ca(OH)2 in the concrete mass, i.e. of its reaction with the atmospheric CO2. The main aim of this work is an experimental investigation and modelling of carbonation process. The effect of relative humidity, curing period and replacement of Portland cement by supplementary cementing materials (SCM - fly ash, blast furnace slag and metakaolin) on carbonation process has been studied. Calcium hydroxide content in the presence of SCM and their pozzolanic activities have been also determined. Furthermore, lots of parametric studies and comparison of carbonation models have been provided. The software tools based on the introduced models and considering the input data to be statistically independent random variables have been described and used for other parametric studies.
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GÓES, Pablo Borba de Barros. "Análise da pozolanicidade por meio da difração de raio-x em pastas de cimento portland e com substituição por cinza do bagaço de cana-de-açúcar." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/20407.

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A incorporação de resíduos diversos dentro de seus processos produtivos tem sido uma tendência na construção civil, esse processo visa a diminuição dos custos de produção e da deposição de resíduos no meio ambiente, dentro desta ótica as cinzas vegetais tem sido bastante estudadas devido as suas possíveis propriedades pozolânica. Para este estudo foi utilizada a cinza do bagaço da cana-de-açúcar (CBCA) proveniente do estado de Pernambuco, esse material foi submetido a um processo de secagem em estufa a 100°C e um peneiramento para retirar matérias contaminantes como folhas, madeiras e outros. O material foi dividido em quatro partes e submetido a um processo de calcinação nas temperaturas de 300°C, 400°C, 500°C e 600°C e chamadas de CB 300, CB 400, CB 500 e CB 600, a parte do material que não passou por esse tratamento foi denominada de CAN. Posteriormente a CBCA passou por um peneiramento em peneiras de malha #200 e #400 e a moagem em um moinho de bolas e por fim essas amostras foram submetidas aos ensaios de caracterizações físicas (Área específica, BET (BrunauerEmmett-Teller) e Massa específica) e caracterização química (D.R.X. e termogravimetria) e ensaios de consistência e resistência a compressão. A existência de atividade pozolânica foi testada através dos ensaios de D.R.X. e resistência a compressão segundo as normas da ABNT NBR 5751 (2012). No ensaios químicos (D.R.X.) ficou constatada a possível existência de atividade pozolânica do material estudado apenas nas cinzas moídas a sete horas, no ensaio de resistência a compressão apenas as cinzas moídas a sete horas apresentaram desempenho satisfatório. O estudo mostrou a importância do processo de moagem do material e de como o mesmo influencia na atividade pozolânica, já o processo de calcinação teve resultados abaixo do esperado principalmente nas temperaturas a partir de 500°C, já que as amostras apresentaram resultados melhores nas temperaturas de 300°C e 400°C.
The incorporation of various waste in their production processes has been a trend in the construction industry, this process is aimed at reducing production costs and waste disposal on the environment, within this perspective plant ash has been widely studied because of its potential pozzolanic properties. For this study we used sugar cane bagasse ashes (CBCA) from the state of Pernambuco, this material was subjected to a drying process in oven at 100 ° C and sieving to remove contaminating materials such as leaves, wood and others. The material was divided into four parts and subjected to a calcination process at temperatures of 300 ° C, 400 ° C, 500 ° C and 600 ° C and calls CB300, BC400, BC500 and BC600, the portion of the material which has not undergone this treatment was designated CAN. Subsequently the CBCA passed a sieve of sieve mesh # 200 and # 400 and grinding in a ball mill and finally the samples were subjected to physical characterization assays (specific surface area, BET (Brunauer-EmmettTeller) and Mass specific) and chemical (DRX and thermogravimetry) and consistency tests and compressive strength. The existence of pozzolanic activity was tested by the D.R.X. tests, thermogravimetry and compressive strength according to ABNT NBR 5751 (2012). In chemical assays (XRD and thermogravimetric analysis) was found to contain the reactivity of the material studied compared to pozzolan reference metakaolin (TCM), as compared to compressive strength testing only the ash grinded to seven hours (M7H) showed satisfactory performance. The study showed the importance of the process of grinding the material and how the same influence on the pozzolanic activity, since the calcination process results below mainly expected at temperatures from 500 ° C, since the samples showed better results in temperatures 300 ° C and 400 ° C.
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Book chapters on the topic "Pozzolanic Activity"

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Lemma, Roxana, Cristina C. Castellano, Viviana L. Bonavetti, Monica A. Trezza, Viviana F. Rahhal, and Edgardo F. Irassar. "Thermal Transformation of Illitic-Chlorite Clay and Its Pozzolanic Activity." In RILEM Bookseries, 266–72. Dordrecht: Springer Netherlands, 2017. http://dx.doi.org/10.1007/978-94-024-1207-9_43.

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Azevedo, A. R. G., J. Alexandre, L. J. T. Petrucci, E. B. Zanelato, and T. F. Oliveira. "Evaluation of the Pozzolanic Activity of Residue From the Paper Industry." In Characterization of Minerals, Metals, and Materials 2017, 657–62. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-51382-9_72.

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Alexandre, J., G. C. Xavier, A. R. G. Azevedo, S. N. Monteiro, and C. M. F. Vieira. "Determination of Temperature and Time Calcination of Clays for Production of Metakaolin Based on Pozzolanic Activity." In Characterization of Minerals, Metals, and Materials 2014, 25–32. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118888056.ch4.

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Moncea, Mihaela-Andreea, György Deák, Florina-Diana Dumitru, Roshazita Che Amat, and Norlia Mohamad Ibrahim. "A Comprehensive Evaluation of Pozzolanic Activity of Ancient Brick Powders Wastes—BPW in Cement Based Materials." In Lecture Notes in Civil Engineering, 229–34. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7920-9_27.

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Danner, Tobias, Geir Norden, and Harald Justnes. "The Effect of Calcite in the Raw Clay on the Pozzolanic Activity of Calcined Illite and Smectite." In RILEM Bookseries, 131–38. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-2806-4_15.

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Xia, Chun, Bing Jie Wang, and Qi Lin Song. "Study on Pozzolanic Activity of Mineral Admixtures in Forms of Li-Salt Industrial Residue and Fly Ash." In Environmental Ecology and Technology of Concrete, 162–66. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-983-0.162.

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Pourkhorshidi, A. R. "Tests to evaluate pozzolanic activity in eco-efficient concrete." In Eco-Efficient Concrete, 123–37. Elsevier, 2013. http://dx.doi.org/10.1533/9780857098993.2.123.

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SISTU, GIOVANNI, CIRILLO ATZENI, LUIGI MASSIDDA, and ULRICO SANNA. "MICROSTRUCTURE AND POZZOLANIC ACTIVITY OF SOME PYROCLASTIC ROCKS FROM SARDINIA (ITALY)." In Blended Cements in Construction, 32–44. CRC Press, 1991. http://dx.doi.org/10.1201/9781482296631-3.

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Conference papers on the topic "Pozzolanic Activity"

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Osterhus, Lennart, Florian Ditz, and Frank Schmidt-Döhl. "Pozzolanic activity of flint powder." In Fifth International Conference on Sustainable Construction Materials and Technologies. Coventry University and The University of Wisconsin Milwaukee Centre for By-products Utilization, 2019. http://dx.doi.org/10.18552/2019/idscmt5060.

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"Pozzolanic Activity of Calcined Clays." In SP-289: Twelfth International Conference on Recent Advances in Concrete Technology and Sustainability Issues (Hard Copy). American Concrete Institute, 2012. http://dx.doi.org/10.14359/51684269.

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"Pozzolanic Activity of Calcined Red Mud." In "SP-132: Fly Ash, Silica Fume, Slag, and Natural Pozzolans and Natural Pozzolans in Concrete - Proceedings Fourth Interna". American Concrete Institute, 1992. http://dx.doi.org/10.14359/2182.

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"Evaluation of Pozzolanic Activity of Rice Husk Ash." In "SP-132: Fly Ash, Silica Fume, Slag, and Natural Pozzolans and Natural Pozzolans in Concrete - Proceedings Fourth Interna". American Concrete Institute, 1992. http://dx.doi.org/10.14359/2009.

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AlArab, Amir, Ghassan Chehab, and Bilal Hamad. "Pozzolanic Activity of Concrete Incorporated Sustainable Materials for Rigid Pavements." In International Airfield and Highway Pavements Conference 2019. Reston, VA: American Society of Civil Engineers, 2019. http://dx.doi.org/10.1061/9780784482469.046.

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Jankovský, Ondřej, Anna-Marie Lauermannová, Daniel Bouša, Vilém Bartůněk, Martina Záleská, Milena Pavlíková, and Zbyšek Pavlík. "Chemical composition, thermal analysis and pozzolanic activity of biomass ash from Miscanthus." In THERMOPHYSICS 2018: 23rd International Meeting of Thermophysics 2018. Author(s), 2018. http://dx.doi.org/10.1063/1.5047611.

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"Comparison of Different Methods for Testing the Pozzolanic Activity of Fly Ashes." In "SP-114: Fly Ash, Silica Fume, Slag, and Natural Pozzolans in Concrete: Proceedings of the Third International Conference". American Concrete Institute, 1989. http://dx.doi.org/10.14359/2113.

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Zaleska, Martina. "POZZOLANIC ACTIVITY OF SEWAGE SLUDGE ASH WITH RESPECT TO ITS CALCINATION AND CHEMICAL COMPOSITION." In 17th International Multidisciplinary Scientific GeoConference SGEM2017. Stef92 Technology, 2017. http://dx.doi.org/10.5593/sgem2017/62/s26.045.

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Al Ghabban, Ahmed, Aseel B. Al Zubaidi, and Zahraa Fakhri. "Pozzolanic activity and durability of nano silica, micro silica and silica gel contained concrete." In TECHNOLOGIES AND MATERIALS FOR RENEWABLE ENERGY, ENVIRONMENT AND SUSTAINABILITY: TMREES18. Author(s), 2018. http://dx.doi.org/10.1063/1.5039206.

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Gu, Bingwei, and Peiming Wang. "Influence of pozzolanic activity of coal gangue on hydration products in coal gangue-cement system." In 2010 International Conference on Mechanic Automation and Control Engineering (MACE). IEEE, 2010. http://dx.doi.org/10.1109/mace.2010.5536553.

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