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Durabilidad de morteros adicionados con FCC expuestos a sulfato de magnesio y sulfato de sodio

2016; Pontifical Catholic University of Chile; Volume: 31; Issue: 3 Linguagem: Inglês

10.4067/s0718-50732016000300004

0718-5073

Silvia Izquierdo, Jherson E. Díaz, Ruby Mejía de Gutiérrez, Janneth Torres Agredo,

Building materials and conservation

This paper presents a comparative analysis of the deterioration of mortars containing 10% and 20% of a fluid catalytic cracking residue (FCC) in the presence of sodium sulfate (Na2SO4) and magnesium sulfate (MgSO4) at 5% (concentration 50g/L).Cement without addition (reference cement), and blended with 10% metakaolin (Cem-10MK) and 10% silica fume (Cem-10SF) were used as reference materials.The longitudinal expansion and loss of compressive strength at 392 days of exposure were evaluated.Additionally, microstructural analysis was performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) to identify the generated products.The results indicate that the residual strength of mortars blended with 10% and 20% of FCC after 360 days of immersion in the Na2SO4 solution is 18.5% higher than the value reported by the standard mixture, and 55% and 39% higher with respect to that reported for the mixtures containing 10% MK and SF.Mortars containing 10% of FCC in the presence of Na2SO4 report a loss of resistance of approximately 10%, while in MgSO4 it was 38% lower than the values of other evaluated mixtures.In general, MgSO4 is a more aggressive solution than Na2SO4.Ettringite and gypsum were identified as products from the reaction with sulfates.