Efeitos da utilização de aceleradores alternativos na hidratação de cimentos Portland com fosfogesso
DOI:
https://doi.org/10.46421/enarc.v8i00.2939Palavras-chave:
Fosfogesso, Aceleradores alternativos, Hidratação, Resistência à compressão, CalorimetriaResumo
O fosfogesso, subproduto do ácido fosfórico, é uma fonte alternativa de sulfato de cálcio à gipsita natural em cimentos. Entretanto, devido à presença de fluoretos (F-) e fosfatos (P2O5) no fosfogesso, há o prolongamento dos tempos de pega e uma redução na resistência mecânica inicial no cimento Portland. Para mitigar esse efeito danoso, uma opção é o uso de aceleradores de hidratação e resistência. Assim, tem-se como objetivo avaliar o efeito da utilização de aceleradores alternativos na hidratação de cimentos com fosfogesso. São eles: cloreto de sódio (NaCl), Cloreto de cálcio (CaCl2), hidróxido de sódio (NaOH), silicato de sódio (Na2SiO3). Ensaios de calorimetria isotérmica e resistência à compressão com 24h foram realizados nas pastas de cimento frescas e endurecidas. NaOH apresentou as resistências mais elevadas enquanto Na2SiO3 exibiu valores inferiores à amostra de referência (REF). CaCl2 mostrou hidratação compatível a R EF enquanto NaCl revelou resistências e calor acumulado superiores.
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