Redefining cement characteristics for sulfate-resistant Portland cement

Evaluation of the SR Portland cement against sodium and magnesium sulfate attack: a physical and comparative analysis of mortars

“…2concentration is high, regarding sulfate attack conditions, C 3 A contents below 9% usually show acceptable performance to sulfates, differently from amounts higher than 12%. While in the range of both shows variable behavior [15]. Tosun-Felekoglu [16] shows results from samples with different amounts of C 3 A (4.6% and 11.2%) and also using limestone filler (0%, 5%, 10%, 20% and 40% in partial replacement of the cement, by mass) exposed to both magnesium and sodium sulfate solutions at two different temperatures (5 and 20 ° C).…”

“…According to Skalny et al [2], C 4 AF can produce ettringite as well, however, at a considerably lower rate than C 3 A, as so cements with lower C 3 A/C 4 AF ratio can are, in general, causes less expansion. Regarding silicates phases of the clinker, as the ratio C 3 S/C 2 S of the clinker increases, greater is be the formation of portlandite after hydration, which results in a concrete more susceptible to sulfate attack [15]. Different author [18] [19] also indicated that there is greater resistance to sulfate attack in cement with low Ca/Si ratio, which also leads to a lower portlandite formation after hydration.…”

“…The decrease in the Ca/Si ratio from 3.65 (ARI) to 2.76 (RS) results in a consequent lower C 3 S content, as well as lower Ca(OH) 2 formation after hydration [18] [19]. Likewise, the decrease on the aluminate amount and an increase in Fe 2 O 3 also have a positive influence on final products susceptible to sulfate attack after hydration [2] [15], since a smaller formation of calcium monosulfoaluminate hydrated, which is directly related to the formation secondary ettringite. However, cement with a lower amount of calcium hydroxide can turn Evaluation of the SR Portland cement against sodium and magnesium sulfate attack: a physical and comparative analysis of mortars the concrete more susceptible to magnesium sulfates attack, due to the possibility of the instability of C-S-H due to o lower pH [20].…”

Capacidade De Adições Minerais Em Mitigar O Ataque Por Sulfatos De Sódio E Magnésio Em Argamassas De Cimento Portland

“…Enquanto que na faixa entre estes valores mencionados, o comportamento do cimento é variável (TIKALSKY et al, 2002 …”

“…Todavia, de forma oposta, para exposição ao 4 , quanto menor o teor de CH, maior o grau do ataque por sulfato de magnésio, caracterizando um comportamento inversamente proporcional. E esta íntima relação entre o teor de CH e o grau do ataque por sulfatos condiz com a bibliografia, como por exemplo, Biczók (1972), Ferraris et al, (1997), Tikalsky et al (2002), Bellmann e Stark (2007), Lee et al (2008), Lothenbach et al (2011), Felekoglu (2012 No mesmo sentido do que foi mostrado para variação de resistência à tração na flexão, baseando-se nas afirmações de Irassar (1990) Ao mesmo tempo, tamanha degradação não foi observada para expansão dimensional linear, logo, conclui-se que parametrizar o ataque por sulfatos apenas pelo comportamento unidimensional pode ocasionar em erros na tomada de decisão para definição dos materiais a serem utilizados.…”