Investigation of concrete exposed to dual sulfate attack

Nehdi, Moncef L.; Suleiman, Ahmed R.; Soliman, Ahmed M.

doi:10.1016/j.cemconres.2014.06.002

Cited by 183 publications

(63 citation statements)

References 12 publications

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“…Chindaprasirt et al (37) proved that silica fume improved the strength and resistance to sulfate of fly ash-based geopolymer. Nehdi et al (38) proposed that partial replacement of cement with pozzolanic complementary materials can improve strength behavior of cement. Saca and Georgescu (39) in their study showed that the presence of both limestone and fly ash in cement does not seem to decrease the vulnerability of cements to magnesium sulfate attack at low temperature.…”

Section: Research Backgroundmentioning

confidence: 99%

A composite cement of high magnesium sulphate resistance

2018

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This study investigates the magnesium sulphate resistance of chemically activated phosphorus slag-based composite cement (CAPSCC). Enough mortar specimens were prepared from phosphorus slag (80 wt.%), type II Portland cement (14 wt.%), and compound chemical activator (6 wt.%) and were exposed to 5% magnesium sulphate solution after being cured. Mortar specimens of both type II and V Portland cements (PC2 and PC5) were also prepared and used for comparison purpose. According to the test results, after 12 months of exposure, PC2, PC5 and CAPSCC exhibited 43.5, 35.2 and 25.2% reduction in compressive strength, 0.136, 0.110, and 0.026% expansion in length, and 0.91, 2.2, and 1.78% change in weight, respectively. Complementary studies by X-ray diffractometry and scanning electron microscopy revealed that CAPSCC has a very low potential for the formation of sulphate attack products, especially ettringite. The results confirm a high magnesium sulphate resistance for CAPSCC compared to PC2 and PC5. RESUMEN:Cemento compuesto de alta resistencia al sulfato de magnesio. Este trabajo aborda el estudio de la resistencia al sulfato de magnesio de un cemento compuesto con base de escoria de fósforo activada química-mente (CAPSCC). Se prepararon muestras de mortero a partir de escoria de fósforo (80% en peso), cemento Portland tipo II (14% en peso) y activador químico (6% en peso) y tras el curado, se expusieron a una solución de sulfato de magnesio al 5%. También se prepararon morteros de cementos Portland de tipo II y V (PC2 y PC5) que se usaron con fines comparativos. De acuerdo a los resultados obtenidos, después de 12 meses de exposición, PC2, PC5 y CAPSCC mostraron un 43.5, 35.2 y 25.2% de reducción en la resistencia a la compresión, 0.136, 0.110, y 0.026% de expansión en longitud, y 0.91, 2.2 y 1.78% de cambio en peso, respectivamente. Estudios complementarios por difracción de rayos X y microscopía electrónica de barrido revelaron que los cementos CAPSCC tienen un potencial muy bajo para la formación de productos de ataque de sulfato, especialmente etringita. Los resultados confirman una alta resistencia al sulfato de magnesio para CAPSCC en comparación con PC2 y PC5

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Section: Research Backgroundmentioning

confidence: 99%

A composite cement of high magnesium sulphate resistance

2018

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“…Although the use of SCMs may aid, delay or prevent sulfate attack, the same cannot be said in the event of physical sulfate attack (Chabrelie, 2010;Irassar et al, 1996;Nehdi et al, 2014). Nehdi et al (2014) investigated partially immersed concrete samples.…”

Section: Effect Of Supplementary Cementitious Materials On Physical Smentioning

confidence: 99%

“…Parallels may be drawn between this study and similar situations arising in concrete. Concrete samples subjected to semi-immersion have been tested in the past, in both field and laboratory conditions (Chabrelie, 2010;Irassar et al, 1996;Nehdi et al, 2014). The immersed portions will be subjected to chemical sulfate attack, whereas the exposed regions will expect to fail due to salt crystallisation.…”

Section: Physical Sulfate Attackmentioning

confidence: 99%

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Current knowledge of external sulfate attack

Whittaker

Black

2015

Advances in Cement Research

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This paper offers an update of the current understanding of sulfate attack, with emphasis on the sulfates present in an external water source percolating through, and potentially reacting with, the cement matrix. The paper considers the explanations put forward to explain sulfate attack, both from a chemical and microstructural perspective.Similarly, this paper reviews work on the physical damage caused by the precipitation of sulfate salts in porous materials. With the increased use of binary and ternary blends, this paper also considers the impact of binder composition on sulfate resistance, and similarly reviews how the nature of the sulfate species can affect the nature and extent of any deterioration. This then leads on to the important consideration of differences between field-and lab-based studies, reviewing the effect of various experimental parameters on sulfate resistance. This latter topic is of great importance to anyone who wishes to carry out such experiments.

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“…In the sodium sulfate resistance test of mortar specimens, minimum weight loss occurred when the cement was replaced by appropriate 10% of glass powder [54]. 4) Immersion position: Nehdi et al investigated the dual sulfate attack performance of concrete partially immersed in a 5% sodium sulfate solution under cycling temperature and relative humidity and concluded that wick action acted as the main transport mechanism of a solution in the partially exposed concrete: the lower portion immersed in sulfate solution could suffer from chemical sulfate attack, while the upper one was sensitive to the intrinsic pore structure and vulnerable to physical sulfate attack [55,56]. 5) Lightweight aggregates and viscosity modifier: Bentz et al explored two new approaches for increasing a mortar's resistance to sulfate attack: on one hand, fine lightweight aggregates were pre-wetted to enhance the microstructure of the interfacial transition zone, on the other hand, the isolated pores in the lightweight aggregates might help to accommodate the formation of expansive degradation products, such as ettringite, without creating substantial stresses and subsequent cracking; a viscosity modifier was added to the concrete mixture to increase the viscosity of the pore solution and thus slowed down the ingress of sulfates from the external environment [57].…”

Section: Deterioration Caused By Sulfate Attackmentioning

confidence: 98%