New insights into long-term chloride transport in unsaturated cementitious materials: Role of degree of water saturation

Zhang, Yong; Ye, Guang; Yang, Zhengxian

doi:10.1016/j.conbuildmat.2019.117677

Cited by 15 publications

(4 citation statements)

References 37 publications

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“…Chloride content and pH are the main factors affecting the reinforcement corrosion of concrete structures [26,27]. Cylindrical paste specimens (ϕ 50 × 100 mm) cured at ages of 1 d, 7 d and 28 d were compressed under high pressure by following the method proposed by Barneyback and Diamond [28].…”

Section: Pore Solution Chemistrymentioning

confidence: 99%

Hydration, Microstructure and Compressive Strength Development of Seawater-mixed Calcium Sulphoaluminate Cement-based Systems

Zhang

Niu

2021

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In-depth understanding of the calcium sulphoaluminate (CSA) cement, a type of environment-friendly cement, is essential for its wide application in engineering practice. Partial replacement of CSA by alternative alumina-rich powders has significant potential in the production of cost-effective CSA cement. In this work various supplementary cementitious materials (SCMs) including slag, metakaolin and silica fume with different replacement levels were added into CSA cement, and mixing with seawater, to prepare paste and concrete specimens. The development of hydration products in the paste specimens was characterized by X-ray diffraction and Thermogravimetric analysis. The pore structures of the seawater-mixed paste specimens obtained from mercury intrusion porosimetry tests, along with the pH value and free chloride content in the pore solution, were analyzed. Results show that various SCMs have significantly different effects on the pore solution chemistry, hydration and microstructural formation of the seawater-mixed CSA cement, resulting in different mechanical behavior and durability properties. The results of this work are helpful for the development of cost-effective CSA cement-based concrete used in marine constructions.

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Section: Pore Solution Chemistrymentioning

confidence: 99%

Hydration, Microstructure and Compressive Strength Development of Seawater-mixed Calcium Sulphoaluminate Cement-based Systems

Zhang

Niu

2021

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“…Field concretes are normally unsaturated, which plays a crucial role in long-term chloride transport. This issue has been highlighted and elaborated on in recent reports [10,11,18]. Based on a comprehensive literature survey, research on chloride penetration and transport mechanisms of unsaturated cementitious systems incorporating ultrafine slag powders are far from adequate.…”

Section: Introductionmentioning

confidence: 99%

Effects of Ultrafine Blast Furnace Slag on the Microstructure and Chloride Transport in Cementitious Systems under Cyclic Drying–Wetting Conditions

Jiang

et al. 2022

Applied Sciences

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This paper presents experimental investigations into the effects of ultrafine blast furnace slag on microstructure improvements against chloride penetration in saturated and unsaturated cementitious systems exposed to cyclic drying–wetting conditions. The hydration kinetics of ultrafine slag powders and pore solution chemistry in slag-blended cementitious systems at different ages, together with the main hydration products and pore structure characteristics, were determined. The chloride profiles accounting for different slag contents and drying–wetting cycles were measured. The results reveal that the reactivity of ultrafine slag can be well described with Avrami’s equation. The dilution effect of the slag predominated the pore solution chemistry, and the pH value decreased with a higher inclusion of slag. An optimal inclusion of 65% slag by mass of the binder corresponding to the finest pore structure and highest hydrotalcite content was found, which provides a reasonable basis for the slow chloride diffusion and high chloride binding. Under drying–wetting exposure, the specimen with a lower saturation exhibited a higher chloride transport caused by capillary absorption in the skin layer. The chloride transport tended to be diffusion controlled after sufficient drying–wetting cycles.

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“…A influência do GS sobre a difusão de íons cloreto tem sido objeto de inúmeras pesquisas, sendo demonstrada a sua importância em modelos de análise de vida útil de estruturas de concreto armado e protendido. Entre vários desses estudos, pode-se citar: Guimarães e Helene (2000,2007), Climent et al (2002Climent et al ( , 2007, Souza (2005), Guimarães et al (2011), Bandeira et al (2015), Moradllo (2017), Savoye et al (2018) e Zhang et al (2020).…”

Section: Introductionunclassified

Estruturas De Concreto Armado Revestidas Com Argamassa: Um Método Para Avaliar O Grau De Saturação E O Coeficiente De Difusão Do Concreto E Argamassa No Mesmo Ambiente, Frente Ao Ataque De Cloretos

Bandeira¹,

Guimarães²,

GONÇALVES³

2022

Anais Do(a) Anais Do Encontro Nacional De Modelagem Computacional, Encontro De Ciência E Tecnologia De Materiais, Conferência S

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Resumo. O grau de saturação do concreto (GS) é relevante na difusão dos cloretos nas estruturas de concreto armado. Visando a durabilidade, diversos estudos foram efetuados nas últimas décadas, mas, raramente contemplaram a atuação da argamassa como revestimento do concreto situado em ambientes sujeitos à ação dos cloretos. Este artigo objetiva o desenvolvimento de método que avalie o GS do concreto e da argamassa e coeficiente de difusão em mesmo ambiente e, através de um modelo matemático, se estabeleça parâmetros para previsão da corrosão no aço. Foram desenvolvidos experimentos, em laboratório, com a utilização de amostras únicas de argamassa e de concreto além de amostras de concreto revestido. Os resultados apurados determinaram que obtenção do GS para o concreto e a argamassa, em amostras compostas, deve ser feito separando-se as partes e medindo o GS de cada, o coeficiente de difusão da argamassa chega a aproximadamente 22 vezes maior do que do concreto e há uma eficiência do revestimento na proteção à armadura do concreto. Assim, conclui-se que utilizando a metodologia proposta, o revestimento de argamassa pode ser considerado nos modelos de vida útil, no entanto, torna-se necessário outros ensaios com variações de traços, argamassa, etc. para a validação desses resultados.

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New insights into long-term chloride transport in unsaturated cementitious materials: Role of degree of water saturation

Cited by 15 publications

References 37 publications

Hydration, Microstructure and Compressive Strength Development of Seawater-mixed Calcium Sulphoaluminate Cement-based Systems

Hydration, Microstructure and Compressive Strength Development of Seawater-mixed Calcium Sulphoaluminate Cement-based Systems

Effects of Ultrafine Blast Furnace Slag on the Microstructure and Chloride Transport in Cementitious Systems under Cyclic Drying–Wetting Conditions

Estruturas De Concreto Armado Revestidas Com Argamassa: Um Método Para Avaliar O Grau De Saturação E O Coeficiente De Difusão Do Concreto E Argamassa No Mesmo Ambiente, Frente Ao Ataque De Cloretos

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