Weathering of Iron Sulfides and Concrete Alteration: Thermodynamic Model and Observation in Dams from Central Pyrenees, Spain

Ayora, Carlos; Chinchón, Servando; Aguado, Antonio; Guirado, F.

doi:10.1016/s0008-8846(98)00019-2

Cited by 45 publications

(36 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Asimismo, y en función de los difractogramas obtenidos, podría afirmarse que la alta cantidad de ión sulfato presente, en parte originado por oxidación de SH 2 , y su acción sobre la portlandita permite la formación de yeso secundario que produce alteraciones en la estructura del cemento (30). Los resultados obtenidos por DRX también muestran que el yeso, originado en parte por la reacción de la portlandita en presencia de sulfatos (31), y la ettringita, ven aumentados sus contenidos con el tiempo de exposición del cemento al medio acuoso, lo que se corresponde con un incremento de la intensidad de sus reflexiones (24).…”

Section: Discussionunclassified

“…The diffractograms indicate that the high amounts of sulfate ions, in part caused by SH 2 oxidation, and their activity on the portlandite, give rise to the formation of secondary gypsum, which in turn causes alterations in the slurry structure (30). The XRD results also show that the gypsum, partly deriving from the portlandite reaction in the presence of sulfates (31), and the ettringite both increase in quantity with exposure time of the hardened slurry to the aqueous medium, visible as an increase in reflection spikes (24).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Ataque del anhídrido carbónico y el ácido sulfhídrico sobre pastas de cemento API clase H expuestas a aguas de formación salinas

Márquez¹,

Sánchez²,

Martín-del-Río³

et al. 2010

Mater. construcc.

View full text Add to dashboard Cite

RESUMENSe simuló la acción agresiva de los denominados iones fundamentales (sulfato, cloruro y magnesio) y los gases agrios presentes en el gas natural (CO 2 y H 2 S) sobre un cemento API clase H utilizado en pozos gasíferos a presión y temperatura elevadas, al objeto de observar sus alteraciones fisicoquímicas por la acción combinada de tales gases y las aguas de formación. Se prepararon varias probetas del material cementante para su inmersión en disoluciones neutras, conteniendo los iones fundamentales en concentraciones fijas, dentro de reactores tipo Parr. Se analizaron durante más de dos meses una serie de disoluciones en contacto con el cemento utilizado; así como, mediante DRX, la evolución de la mineralogía de dicho material entre los 14 y los 60 días. Los principales efectos de ambos gases, en conjunto o por separado, sobre la durabilidad del cemento fueron, respectivamente, la formación de carbonato cálcico y la lixiviación de algunos componentes.Palabras clave: cementos para pozos de petróleo, durabilidad, pasta de cemento, difracción de rayos X, fases cristalinas. SUMMARYThis paper discusses the attack of the major ions (sulfate, chloride, and magnesium) and sour gases, present in natural gas (CO 2 y SH 2 ), on API class H cement, the type used in gas wells under high pressure and temperature. The effects of these chemical agents on this cement was simulated to study the physicochemical changes due to the action of sour gases and formation water. Cement specimens were immersed in neutral solutions containing fixed concentrations of the major ions inside Parr reactors. These solutions were analysed and XRD analyses were conducted for over two months to identify mineralogical variations from 14 to 60 days. The objective of this research was to determine the effects of the joint attack of major ions and sour gases on cement pastes. The main effects of both gases, jointly or separately, on cement durability were, respectively, the carbonation process and the leaching of some components.Keywords: petroleum wells cemen, durability, cement slurries, XRD , crystalline phases. INTRODUCCIÓNLos denominados gases agrios, anhídrido carbónico y ácido sulfhídrico, significativamente presentes en la mayoría de yacimientos de gas y petróleo (1), pueden provocar importantes cambios fisicoquímicos sobre el cemento colocado entre el revestidor de un pozo y las formaciones rocosas (2); dicho material cementante se deteriora con el tiempo al ser atacado por ambos gases, sobre todo en presencia de ciertos iones (sulfato, cloruro o magnesio) contenidos en concentraciones que superan los 40.000 ppm en las aguas de formación en contacto con el cemento (3). Las concentraciones del ácido sulfhídrico y anhídrido carbónico en el gas natural suelen arrojar valores no superiores al 10% y 30% molar, respectivamente (4). Los gases agrios se disuelven en medio acuoso produciendo una serie de iones (sulfuro, carbonato, etc.) que afectan significativamente a la durabilidad del cemento en los pozos de gas y petróleo, influyendo sobre l...

show abstract

Section: Discussionunclassified

Section: Discussionmentioning

confidence: 99%

Ataque del anhídrido carbónico y el ácido sulfhídrico sobre pastas de cemento API clase H expuestas a aguas de formación salinas

Márquez¹,

Sánchez²,

Martín-del-Río³

et al. 2010

Mater. construcc.

View full text Add to dashboard Cite

show abstract

“…Once the sulfate ions are released, the attack is much faster [2] [4]. The rate of aggregate sulfide oxidation depends on the oxygen diffusion through the oxide layer (hydroxide) formed around the sulfide grains and the subsequent change of their surface area.…”

Section: Concrete Produced With Aggregates Containing Sulfates and Sumentioning

confidence: 99%

“…Aggregates containing iron sulfides were used in Graus and Tavascán dams in Spain in 1992, as well as in buildings in Maresme also in Spain in 1970. Chinchón et al [3], Ayora et al [4] and Araújo et al [5] reported serious concrete cracking and degradation in all the above-mentioned structures. To investigate further this pathological phenomenon, these authors carried out microscopic tests in extracted samples from these structures and found compounds different from those usually produced in the cement hydration of cement.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of pyrite and pyrrhotite in concretes

Marcelino

Calixto

Gumieri

et al. 2016

Rev. IBRACON Estrut. Mater.

View full text Add to dashboard Cite

ResumoIt is well known that aggregate characteristics can intensively interfere in concrete behavior especially when sulfides are presented in the aggregates. The lack of consensus to content limit value of these deleterious sulfur compounds in concrete structures for dams has motivated several investigations worldwide. Within this scenario, this work presents a methodology to evaluate the presence of pyrite and pyrrhotite in concretes produced with aggregates containing sulfides. For the study, rock samples from the Irapé hydroelectric power plant area in Minas Gerais (Brazil) were used. This plant was built in a geological site where the rock presented sulfide levels of at least 3%. These rock samples were first ground and then used as aggregates in mortars, which were, during almost one year, subjected to three different exposed conditions: temperature of 23° ± 2°C and relative humidity of 95 to 100%; calcium hydroxide solution diluted in water kept at two different temperatures: room temperature and 50° C. The presence and amount of pyrrhotite were obtained from a leaching process of the material (aggregate or mortar) in a solution of hydrochloric acid. This procedure allowed also the evaluation of the pyrite content. The results showed that the amount of pyrite has remained virtually constant over time in the three exposure situations. This finding indicates that sulfur limits in aggregates should be set according to the type of iron sulfide presented and not solely by the total amount of sulfur.Keywords: sulfide aggregates, concrete, behavior, dams.As características dos agregados podem interferir intensamente no comportamento do concreto, especialmente quando sulfetos, como pirita e pirrotita, estão presentes nos agregados. A falta de consenso para o valor limite do teor desses compostos de enxofre em estruturas de concreto de barragens tem motivado várias investigações em todo o mundo. Dentro desse cenário, este trabalho apresenta uma metodologia para a avaliação da presença desses compostos de enxofre em concretos fabricados com agregados contendo sulfetos. Para o estudo, foram utilizadas amostras de rochas da área de usina hidrelétrica do Irapé, em Minas Gerais (Brasil). Esta usina foi construída em um sítio geológico onde a rocha apresentava níveis de sulfeto de pelo menos 3%. Essas amostras de rochas foram moídas e depois utilizadas como agregados em argamassas submetidas durante aproximadamente um ano a três diferentes condições de exposição: temperatura de 23° ± 2ºC e umidade relativa de 95 a 100%; solução de hidróxido de cálcio diluída em água mantida em duas temperaturas diferentes: temperatura ambiente e 50°C ± 2ºC. A presença e quantidade de pirrotita foram obtidas a partir de um processo de lixiviação do material (agregado ou argamassa) numa solução de ácido clorídrico para dissolução desta, o que permitiu a avaliação do teor de pirita, sulfeto esse não dissolvido pelo ácido clorídrico. A quantidade de pirrotita foi obtida pela diferença entre o valor inicial de enxofre total da amost...

show abstract

“…It is known that sulphate-bearing minerals of pyrites and pyrrhotites undergo oxidation, producing sulphuric acid and degradation within the cementitious matrix (Oberholster et al 1984;Bromley 2015;Rodrigues et al 2012;Tagnit-Hamou et al 2005;Cody et al 1997;Thomas et al 1989;Shayan 1988;Ayora et al 1998). However, there are hardly any research papers concerning the interaction between AMD and concrete.…”

Section: Introductionmentioning

confidence: 99%

Disintegration of concrete construction induced by acid mine drainage attack

Ekolu

Diop²,

Azene

et al. 2016

J. S. Afr. Inst. Civ. Eng.

View full text Add to dashboard Cite

This paper presents findings from microanalytical investigation conducted on disintegrated concrete that had been used to construct a weir within a coal mine in South Africa. The concrete was in contact with polluted mine water, commonly referred to as acid mine drainage (AMD). Accordingly, the weir had been exposed to AMD decant which led to disintegration of concrete due to chemical attack. Investigations were conducted by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD). The field samples examined consisted of soft, broken concrete chunks and a whitish powdery substance that had crystallised and formed a surface coating on certain cracked locations on the deteriorated concrete. No evidence of pyrite oxidation was found in the investigation. The observed deterioration is discussed in relation to acid attack mechanism and its possible co-existence with external sulphate attack process.

show abstract

Weathering of Iron Sulfides and Concrete Alteration: Thermodynamic Model and Observation in Dams from Central Pyrenees, Spain

Cited by 45 publications

References 9 publications

Ataque del anhídrido carbónico y el ácido sulfhídrico sobre pastas de cemento API clase H expuestas a aguas de formación salinas

Ataque del anhídrido carbónico y el ácido sulfhídrico sobre pastas de cemento API clase H expuestas a aguas de formación salinas

Evaluation of pyrite and pyrrhotite in concretes

Disintegration of concrete construction induced by acid mine drainage attack

Contact Info

Product

Resources

About